Ge-gen decoction alleviates primary dysmenorrhoea symptoms in a rat model.

BACKGROUND: Existing treatments for primary dysmenorrhoea (PD), such as NSAIDs, impart side effects. Ge-Gen decoction (GGD), a traditional Chinese medicine, has shown promise in treating PD, but its exact mechanisms remain unclear. Here, we aimed to investigate the efficiency of GGD in alleviating PD using a rat model to understand its precise mechanism of action. METHODS: We established a rat model of dysmenorrhoea induced by oestradiol and oxytocin. The PD rats were administered GGD or Ibuprofen (positive control) intragastrically once daily for seven consecutive days. Serum levels of prostaglandin E2 (PGE2), prostaglandin F2 alpha (PGF2α), ß-endorphin (ß-EP), thromboxane B2 (TXB2), 6-keto-prostaglandin F1α (6-keto-PGF1α) were determined using an enzyme-linked immunosorbent assay (ELISA). The expression levels of oestrogen receptor alpha (ERα) and cyclooxygenase-2 (COX-2) in uterine tissue were measured using immunohistochemical assays, and those of phosphorylated and total extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) were assessed using western blot analysis. RESULTS: Treatment with GGD significantly reduced writhing behaviour, histopathological scores, and levels of COX-2, PGE2, and PGF2α in the serum of PD rats. Additionally, GGD increased ß-EP content and inhibited ERK1/2 activation and ERα expression in uterine tissues. CONCLUSIONS: The results of this study suggest that GGD alleviates PD in rats by suppressing the COX-2-mediated release of PGE2 and PGF2α, modulating the ERα/ERK1/2/COX-2 pathway, and increasing ß-EP content. These results provide insights into the potential mechanisms of GGD in treating PD and support its further investigation as an alternative therapy for this condition.

Ge-Gen decoction is commonly used to alleviate primary dysmenorrhoea. However, its anti-dysmenorrhoea mechanism remains elusive. In this study, using a rat model of primary dysmenorrhoea, we demonstrate that Ge-Gen decoction reduced the levels of cyclooxygenase-2, prostaglandin E2, and prostaglandin F2 alpha in serum and phosphorylated extracellular signal-regulated protein kinases 1 and 2 in the uterus. These results suggest that Ge-Gen decoction alleviates primary dysmenorrhoea via inactivation of the oestrogen receptor alpha/extracellular signal-regulated protein kinases 1 and 2/cyclooxygenase-2 pathway. This study enhances our understanding of the pathogenesis of primary dysmenorrhoea and may potentially inform the development of novel treatment approaches.

Deciphering feedback regulation of prostaglandin F2α in blood stasis syndrome using nitrogen-doped porous transition metal carbides.

Blood stasis syndrome (BSS) has persistent health risks; however, its pathogenesis remains elusive. This obscurity may result in missed opportunities for early intervention, increased susceptibility to chronic diseases, and reduced accuracy and efficacy of treatments. Metabolomics, employing the matrix-assisted laser desorption/ionization (MALDI) strategy, presents distinct advantages in biomarker discovery and unraveling molecular mechanisms. Nonetheless, the challenge is to develop efficient matrices for high-sensitivity and high-throughput analysis of diverse potential biomarkers in complex biosamples. This work utilized nitrogen-doped porous transition metal carbides and nitrides (NP-MXene) as a MALDI matrix to delve into the molecular mechanisms underlying BSS pathogenesis. Structural optimization yielded heightened peak sensitivity (by 1.49-fold) and increased peak numbers (by 1.16-fold) in clinical biosamples. Validation with animal models and clinical serum biosamples revealed significant differences in metabolic fingerprints between BSS and control groups, achieving an overall diagnostic efficacy of 0.905 (95% CI, 0.76-0.979). Prostaglandin F2α was identified as a potential biomarker (diagnostics efficiency of 0.711, specificity = 0.7, sensitivity = 0.6), and pathway enrichment analysis disclosed disruptions in arachidonic acid metabolism in BSS. This innovative approach not only advances comprehension of BSS pathogenesis, but also provides valuable insights for personalized treatment and diagnostic precision.

[Therapeutic effect of Leonuri Herba aqueous decoction on primary dysmenorrhea in rats and its metabolomic analysis].

This study aimed to investigate the therapeutic effect of Leonuri Herba aqueous decoction on primary dysmenorrhea(PD) and explore the underlying mechanism in conjunction with untargeted metabolomics. Forty adult female rats were randomly divi-ded into a normal group, a model control group, ibuprofen(0.12 g·kg~(-1)) group, and high-and low-dose Leonuri Herba aqueous decoction(5 and 2.5 g·kg~(-1)) groups, with eight rats in each group. The PD rat model was prepared using intramuscular injection of estradiol benzoate combined with intraperitoneal injection of pitocin. Drugs were administered by gavage from the 4th day of modeling for 7 d. After the last administration, pitocin was injected intraperitoneally, and the writhing latency and writhing times within 30 min were recorded. The uterine and ovarian coefficients were determined. Estradiol(E_2), progesterone(Prog), oxytocin(OT), cyclooxyge-nase 2(COX-2), prostaglandin E_2(PGE_2), prostaglandin F_(2α)(PGF_(2α)), and Ca~(2+) levels in uterine tissues were measured by ELISA and biochemical kits. Morphological changes in uterine and ovarian tissues were observed by hematoxylin-eosin(HE) staining. The protein expression of oxytocin receptor(OTR), prostaglandin E_2 receptor 3(EP3), and estrogen receptor alpha(ERα) in uterine tissues was detected by immunohistochemistry. The mRNA expression of OTR, PGE_2 receptors 1-4(EP1, EP2, EP3, and EP4), and PGF_(2α) receptor(FP) in uterine tissues was detected by quantitative real-time PCR. Untargeted metabolomics analysis was performed by ultra-high-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry(LC-QTOF-MS) technology to screen potential biomarkers and enrich metabolic pathways. The results showed that Leonuri Herba was able to significantly reduce the writhing times in PD rats(P<0.05 or P<0.01), significantly reduce the uterine and ovarian coefficients(P<0.01), and improve their histomorphology. After treatment with Leonuri Herba, PGE_2 content was significantly increased(P<0.05), COX-2, PGF_(2α) and Ca~(2+) content, and PGF_(2α)/PGE_2 was significantly decreased(P<0.05 or P<0.01), and OT content was decreased, while E_2 and Prog content tended to further increase in uterine tissues of PD rats. Correspondingly, OTR and EP3 protein expression was significantly downregulated(P<0.05 or P<0.01) and ERα protein expression was upregulated(P<0.05) in uterine tissues. The mRNA expression of FP and EP4 in uterine tissues was significantly downregulated(P<0.01), and the mRNA expression of EP1, EP3, and OTR showed a decreasing trend. The untargeted metabolomics results showed that 10 differential metabolites were restored in the plasma of PD rats after Leonuri Herba treatment. The results indicate that Leonuri Herba is effective in the prevention and treatment of PD, and the underlying mechanism may be attributed to the regulation of PGs synthesis and corresponding receptor binding.

Mechanisms of acupuncture for primary dysmenorrhea based on PI3K/Akt/mTOR signaling pathway in rats. / 基于PI3K/Akt/mTORä¿¡å·é€šè·¯æŽ¢è®¨ç”µé’ˆæ²»ç–—åŽŸå‘æ€§ç—›ç»å¤§é¼ çš„æœºåˆ¶.

OBJECTIVES: To observe the effect of electroacupuncture(EA) on phosphatidylinositol-3-kinases(PI3K)/protein kinase B(Akt)/mammalian target of rapamycin(mTOR) signaling pathway of uterus tissue in rats with primary dysmenorrhea(PDM), so as to investigate its mechanisms underlying improvement of PDM. METHODS: Thirty healthy non-pregnant female SD rats were randomly divided into blank, model and EA groups, with 10 rats in each group. The PDM model was established by subcutaneous injection of estradiol diphenhydrate combined with intraperitoneal injection of oxytocin. For rats of the EA group, EA(50 Hz, a tolerable current intensity) was applied to "Guanyuan"(CV4) and bilateral "Sanyinjiao"(SP6) for 20 min, once a day for 10 consecutive days. The number of writhing, wri-thing score, and writhing latency were observed. The uterine histopathological changes were observed by H.E. staining, and the ultrastructural changes of uterine tissue cells in each group were observed by transmission electron microscopy. The contents of prostaglandin E2(PGE2), prostaglandin F2α(PGF2α) and ratios of PGF2α/PGE2 in the serum and uterine tissue were detected by ELISA. The relative expression levels of PI3K, Akt and mTOR and their phosphorylation proteins in the uterine tissue were detected by Western blot and the ratios were calculated. RESULTS: Compared with the blank group, the number and score of writhing, latency of writhing, pathological injury score, contents of PGF2α and ratios of PGF2α/PGE2 in the serum and uterine tissue, and the levels of p-PI3K/PI3K, p-Akt/Akt and p-mTOR/mTOR in the uterine tissue were significantly increased in the model group(P<0.01, P<0.05), while contents of PGE2 in the serum and uterine tissue were reduced(P<0.05). In comparison with the model group, the number of writhing and writhing score, pathological injury score, contents of PGF2α and ratios of PGF2α/PGE2 in both the serum and uterine tissue, the levels of p-PI3K/PI3K, p-Akt/Akt and p-mTOR/mTOR were obviously decreased(P<0.05, P<0.01), whereas the writhing latency was considerably prolonged in the EA group(P<0.01), with elevated contents of PGE2 in the serum and uterine tissue(P<0.05). H.E. staining showed slight dilation of uterine glandular cavity, and severe endometrial edema with extensive cell shedding and a large number of vacuole-like degeneration, apoptosis, pyknosis or fragmentation or disappearance of the nucleus, and neutrophil infiltration in the model group, which were relatively milder in the EA group. Ultrastructural results showed irregular fibroblasts of uterine tissue cells, obvious cytoplasmic edema, reduction in cytoplasmic electron density, seriously irregular nuclei, severe edema of mitochondria with dissolved matrix, fracture and disappearance of mitochondrial crests and vacuolation, and moderate dilation of rough endoplasmic reticulum in the model group, which were milder in the EA group. CONCLUSIONS: EA can improve pain and uterine inflammatory response in PDM rats, which may be associated with its functions in reducing uterine PGF2α and down-regulating PI3K/Akt/mTOR signaling.

Peony Pollen Protects against Primary Dysmenorrhea in Mice by Inhibiting Inflammatory Response and Regulating the COX2/PGE2 Pathway.

Peony pollen contains multiple nutrients and components and has been used as a traditional Chinese medicine with a long history, but the effect of the treatment of primary dysmenorrhea remains to be clarified. The aim of this study is to investigate the therapeutic effect of peony pollen on primary dysmenorrhea mice and the potential mechanism. A uterus contraction model in vitro and primary dysmenorrhea mice were used to evaluate the treatment effect of peony pollen on primary dysmenorrhea. The primary dysmenorrhea mice were treated with 62.5 mg/kg, 125 mg/kg, or 250 mg/kg of peony pollen, and the writhing response, latency period, histopathological changes in the uterus, prostaglandin E2 (PGE2) and prostaglandin F2α (PGF2α) levels, and infiltration of neutrophils and macrophages were investigated. Protein expression of interleukin 1 ß (IL-1ß), interleukin 6 (IL-6), NOD-like receptor thermal protein domain associated protein 3 (NLRP3), cyclooxygenase-2 (COX-2), microsomal prostaglandin-E synthase 1 (mPGEs-1), BCL2-Associated X (Bax), B-cell lymphoma-2 (BCL-2), caspase-3, and cleaved caspase-3 were detected by Western blot, and the oxidative stress related marker malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and reactive oxygen species (ROS) were evaluated. Peony pollen could attenuate spontaneous or oxytocin-induced uterus contractions in vitro. Moreover, peony pollen decreased the writhing times, prolonged the writhing latency, and reduced the pathological damage of uterine tissues. Furthermore, the inflammatory cell infiltration and the protein expression of IL-1ß, IL-6, and NLRP3 were decreased. The COX-2/PGE2 pathway was inhibited; oxidative stress and apoptosis in the uterus also improved in the uterus of primary dysmenorrhea mice. Peony pollen exerts a positive effect on primary dysmenorrhea by inhibiting the inflammatory response and modulating oxidative stress and apoptosis by regulating the COX-2/PGE2 pathway.

Efficacy of prostaglandin E2 versus prostaglandin F2 alpha assisted with narrowband-UVB in stable vitiligo.

In the recent decades, prostaglandins were recommended as a new therapeutic modality of stable vitiligo with promising efficacy. Therefore, we designed the current work to compare the significance of two different subtypes of prostaglandins [prostaglandin E2 (PGE2) versus prostaglandin F2 alpha (PGF2α)], assisted with NB-UVB phototherapy, in treatment of stable vitiligo. This study was conducted on 30 patients with stable non-segmental vitiligo. Three approximately similar vitiliginous areas were chosen in each patient and assigned into 3 groups. Each group treated with intradermal injection of either PGE2 (group I), PGF2α (group II), or saline as placebo (group III) at frequency once/week for 12 weeks. Concomitantly, all groups received NB-UVB phototherapy twice weekly for 3 months. The outcomes of this study discovered that the therapeutic efficacy of intradermal injection of either PGE2 or PGF2α assisted with NB-UVB phototherapy was comparable with non-significant difference between them in spite of being significantly higher than NB-UVB alone. However, there were a significantly earlier onset of repigmentation and higher degree of satisfaction regarding areas treated with PGE2 than those treated with PGF2α. In conclusion, both PGF2α and PGE2 intradermal injection could be considered as quite simple and affordable techniques in the treatment of stable vitiligo with no reported side effects and good patient satisfaction.

Endocrine changes during the peripartal period related to colostrogenesis in mammalian species.

This review discusses endocrine and functional changes during the transition from late gestation to lactation that are related to the production of colostrum in different mammalian species. Species covered in this article include ungulate species (cattle, sheep, goats, pigs, horses), rodents (rat, mouse), rabbits, and carnivores (cats, dogs), as well as humans. An immediate availability of high quality colostrum for the newborn after birth is crucial in species where a transfer of immunoglobulins (Ig) does not or only partially occur via the placenta during pregnancy. Declining activity of gestagens, in most species progesterone (P4), is crucial at the end of pregnancy to allow for the characteristic endocrine changes to initiate parturition and lactation, but the endocrine regulation of colostrogenesis is negligible. Both, the functional pathways and the timing of gestagen withdrawal differ considerably among mammalian species. In species with a sustaining corpus luteum throughout the entire pregnancy (cattle, goat, pig, cat, dog, rabbit, mouse, and rat), a prostaglandin F2α (PGF2α)-induced luteolysis shortly before parturition is assumed to be the key event to initiate parturition as well as lactogenesis. In species where the gestagen production is taken over by the placenta during the course of gestation (e.g., sheep, horse, and human), the reduction of gestagen activity is more complex, as PGF2α does not affect placental gestagen production. In sheep the steroid hormone synthesis is directed away from P4 towards estradiol-17ß (E2) to achieve a low gestagen activity at high E2 concentrations. In humans the uterus becomes insensitive to P4, as parturition occurs despite still high P4 concentrations. However, lactogenesis is not completed as long as P4 concentration is high. Early colostrum and thus Ig intake for immune protection is not needed for the human newborn which allows a delayed onset of copious milk secretion for days until the placenta expulsion causes the P4 drop. Like humans, horses do not need low gestagen concentrations for successful parturition. However, newborn foals need immediate immune protection through Ig intake with colostrum. This requires the start of lactogenesis before parturition which is not fully clarified. The knowledge of the endocrine changes and related pathways to control the key events integrating the processes of colostrogenesis, parturition, and start of lactation are incomplete in many species.

This manuscript reviews and compares hormonal and functional changes occurring in the conceptus (embryo and its extra-embryonic membranes) and their effects on the mammary gland during development from pregnancy to colostrum formation and milk production in multiple mammalian species. Declining activity of gestagens at the end of pregnancy is crucial to allow for both parturition and onset of milk production in most mammals. Strategies to achieve this state of low gestagen activity are different among species. In species where the corpus luteum is sustained throughout the entire pregnancy, luteolysis is the key event to initiate parturition and onset of milk secretion (cattle, goat, pig, cat, dog, rat, mouse, rabbit). However, in species where the placenta takes over gestagen production during the course of pregnancy, the achievement of a state of low gestagen activity is more complex. It ranges from redirection of the hormone production pathway away from gestagens in sheep, to decreasing sensitivity of the uterus towards gestagens in humans. In the horse, there is evidence pointing towards redirection of the hormone production as well as a decrease in sensitivity towards gestagens, but the exact mechanisms are still not clarified.

Effects of source of supplementary trace minerals in pre- and postpartum diets on reproductive biology and performance in dairy cows.

Our objectives were to evaluate the effects of complete replacement of inorganic salts of trace minerals (STM) with organic trace minerals (OTM) in both pre- and postpartum diets on ovarian dynamics, estrous behavior measured by sensors, preimplantation conceptus development, and reproductive performance in dairy cows. Pregnant cows and heifers (n = 273) were blocked by parity and body condition score and randomly assigned to either STM or OTM diets at 45 ± 3 d before their expected calving. Pre- and postpartum diets were formulated to meet 100% of recommended levels of each trace mineral in both treatments, taking into consideration both basal and supplemental levels. The final target concentrations of Co, Cu, Mn, Se, and Zn were, respectively, 0.25, 13.7, 40.0, 0.3, and 40.0 mg/kg in the prepartum diet, and 0.25, 15.7, 40.0, 0.3, and 63.0 mg/kg in the postpartum diet. The STM group was supplemented with Co, Cu, Mn, and Zn sulfates and sodium selenite, while the OTM group was supplemented with Co, Cu, Mn, and Zn proteinates and selenized yeast. Treatments continued until 156 d in milk (DIM) and were assigned to individual cows using automatic feeding gates. Starting at 21 DIM, ultrasonography examinations of the ovaries were performed weekly to determine the presence of a corpus luteum and postpartum resumption of ovarian cyclicity. Cows were presynchronized with 2 injections of PGF2α at 42 and 56 DIM. Estrous behavior was monitored using electronic activity tags that indirectly measured walking activity. Cows detected in estrus after the second PGF2α were inseminated, and those not detected in estrus by 67 DIM were enrolled in a synchronization program. Cows that returned to estrus after artificial insemination (AI) were reinseminated. Pregnancy diagnosis was performed 33 d after AI, and nonpregnant cows were resynchronized. Transcript expression of interferon-stimulated genes in peripheral blood leukocytes was performed in a subgroup of cows (STM, n = 67; OTM, n = 73) on d 19 after AI. A different subgroup of cows (28 STM, 29 OTM) received uterine flushing 15 d after AI for recovery of conceptuses and uterine fluid for analyses of transcriptomics and metabolomics, respectively. In addition, dominant follicle diameter, luteal size and blood flow, and concentration of progesterone in plasma were measured on d 0, 7, and 15 relative to AI. After flushing, PGF2α was given and the dominant follicle was aspirated 2 d later to measure the concentration of trace minerals by mass spectrometry. Estrous behavior, size of the dominant follicle and corpus luteum, concentration of progesterone, time to pregnancy, and proportion of cows pregnant by 100 d of the breeding period did not differ between treatments. A greater proportion of cows supplemented with OTM had a corpus luteum detected before presynchronization (64.3 vs. 75.2%), and primiparous cows supplemented with OTM tended to resume cyclicity earlier than their STM counterparts. Cows supplemented with OTM had a greater concentration of Cu in follicular fluid than cows supplemented with STM (0.89 vs. 0.77 µg/mL, respectively). In pregnant multiparous cows, expression of receptor transporter protein 4 in peripheral blood leukocytes was 42% greater in the OTM group. Conceptuses of the 2 treatments had 589 differentially expressed transcripts, with many indicating advanced conceptus elongation and greater transcript expression of selenoproteins in the OTM group. In pregnant cows, 24 metabolites were more abundant in the uterine fluid of OTM, including spermidine, sucrose, and cholesterol. In conclusion, replacing STM with OTM caused modest improvements to resumption of ovarian cyclicity and important changes in preimplantation conceptus development, but it did not alter conception risk and pregnancy rate.

Conjugated linoleic acid supplementation changes prostaglandin concentration ratio and alters the expression of genes involved in maternal-fetal recognition from bovine trophoblast cells in vitro.

Early embryonic mortality caused by maternal-fetal recognition failure in the three weeks after fertilization represents a major cause of reproductive inefficiency in the cattle industry. Modifying the amounts and ratios of prostaglandin (PG) F2α and PGE2 can benefit the establishment of pregnancy in cattle. Adding conjugated linoleic acid (CLA) to endometrial and fetal cells culture affects PG synthesis, but its effect on bovine trophoblast cells (CT-1) is unknown. The aim of this study was to determine the effects of CLA (a mixture of cis- and trans-9, 11- and -10,12-octadecadienoic acids) on PGE2 and PGF2α synthesis and the expression of transcripts involved with maternal-fetal recognition of bovine trophectoderm. Cultures of CT-1 were exposed to CLA for 24, 48 and 72 h. Transcript abundance was determined by qRT-PCR and hormone profiles were quantified by ELISA. The PGE2 and PGF2α concentrations were reduced in the culture medium of CLA-exposed CT-1 compared to that of unexposed cells. Furthermore, CLA supplementation increased the PGE2:PGF2α ratio in CT-1 and had a quadratic effect (P < 0.05) on the relative expression of MMP9, PTGES2, and PTGER4. The relative expression levels of PTGER4 were reduced (P < 0.05) in CT-1 cultured with 100 µM CLA than in the unsupplemented and 10 µM-CLA groups. Treatment of CT-1 with CLA decreased PGE2 and PGF2α synthesis but a biphasic effect of CLA was observed on the PGE2:PGF2α ratio and relative abundance of transcripts with 10 µM CLA providing maximal improvements in each endpoint. Our data suggest that CLA may influence eicosanoid metabolic process and extracellular matrix remodeling.

[Effects of electroacupuncture on N-methyl-D-aspartate receptor and mitogen activated protein kinase in spinal cord of rats with primary dysmenorrhea].

OBJECTIVE: To observe the effects of electroacupuncture (EA) on the expression levels of N-methyl-D-aspartate receptor (NMDAR), extracellular signal-regulated kinase (ERK)1/2, p38 mitogen activated protein kinase (p38 MAPK) and c-Jun N-terminal kinase (JNK) in the spinal cord of rats with primary dysmenoramia (PDM), so as to explore the underlying mechanism of EA treating PDM. METHODS: Thirty female SD rats were randomly divided into normal group, model group and EA group, with 10 rats in each group. The PDM rat model was established by subcutaneous injection of estradiol benzoate and oxytocin into the thigh. At the same time of modeling, rats in the EA group were treated with EA (50 Hz) at "Sanyinjiao" (SP36) and "Guanyuan" (CV4) once daily, 20 min each time, for 10 consecutive days. The writhing times, writhing score and writhing latency were observed within 30 min after oxytocin injection. The uterine pathological morphology was observed by HE staining, and pathological score was calculated. Serum prostaglandin F2α (PGF2α) and prostaglandin E2 (PGE2) were determined by ELISA. The protein expression levels of NMDAR, ERK1/2, p38MAPK and JNK in spinal cord were detected by Western blot. RESULTS: Compared with the normal group, the writhing times and writhing score were significantly increased (P<0.05); the endometrial epithelial cells showed vacuolar degeneration, death and hyperemia, the uterine pathological score was increased (P<0.05); the content of serum PGF2α and the ratio of PGF2α/PGE2 were significantly increased (P<0.01), while the content of serum PGE2 was significantly decreased (P<0.01); the expression levels of NMDAR, ERK1/2, p38MAPK and JNK in spinal cord were significantly increased (P<0.05, P<0.01) in the model group. Compared with the model group, the writhing times and writhing score were significantly decreased (P<0.05), the writhing latency was prolonged (P<0.05); the endometrial epithelial cells still showed vacuolar degeneration, death and hyperemia, and the uterine pathological score was decreased (P<0.01); the content of serum PGF2α and the ratio of PGF2α/PGE2 were significantly decreased (P<0.01), while the content of serum PGE2 was significantly increased (P<0.01); the protein expression levels of ERK1/2 and JNK in spinal cord were significantly decreased (P<0.01) in the EA group. CONCLUSION: EA intervention at SP36 and GV4 has obvious analgesic effect on PDM rats, and its mechanisms may be related to reducing serum prostaglandin, alleviating uterine inflammation, and inhibiting the protein expressions of NMDAR, ERK1/2, p38 MAPK and JNK in spinal cord.

[Effects of electroacupuncture on NLRP3 inflammasome and pyroptosis protein GSDMD in uterine tissue in rats with primary dysmenorrhea].

OBJECTIVE: To observe the effects of electroacupuncture (EA) on NLRP3 inflammasome and its downstream protein gastermin D (GSDMD) in rats with primary dysmenorrhea (PDM), and to explore the potential mechanism of EA on the treatment of PDM. METHODS: Forty healthy female SD rats without pregnancy were randomly divided into a control group, a model group, an EA group and an ibuprofen group, 10 rats in each group. PDM model was prepared by injection of estradiol benzoate and oxytocin. Except the control group, the rats in each group were subcutaneously injected with estradiol benzoate for 10 days, and oxytocin was injected on the 11th day. The rats in the EA group were intervened with EA (dense wave, frequency of 50 Hz) at "Guanyuan" (CV 4) and "Sanyinjiao" (SP 6) at the same time of modeling, once a day, 20 min each time, for 10 consecutive days. The rats in the ibuprofen group were treated with 0.8 mL of ibuprofen by gavage (concentration of ibuprofen solution was 1.25 mg/mL) for 10 consecutive days. After modeling, the writhing reaction was observed. After intervention, the HE staining method was used to observe the histological morphology of uterus and evaluate the pathological damage score of uterus; ELISA method was used to detect the serum levels of prostaglandin E2 (PGE2) and prostaglandin F2α (PGF2α); Western blot method was used to detect the protein expression of NLRP3, apoptosis related spot like protein (ASC), caspase-1, GSDMD, GSDMD-N and inflammatory factors (interleukin [IL]-1ß, IL-18) in uterine tissue. RESULTS: In the model group, a large number of vacuolar degeneration and death of endometrial epithelial cells, spiral arterioles congestion in lamina propria and neutrophil infiltration were observed. In the EA group, there was a small amount of vacuolar degeneration and death of endometrial epithelial cells, a small amount of spiral arterioles congestion in the lamina propria, and a small amount of neutrophils infiltration. In the ibuprofen group, there was very small number of degeneration and death of endometrial epithelial cells, and no obvious arterial congestion was found in lamina propria, and neutrophil infiltration was occasionally seen. Compared with the control group, in the model group the number of writhing was increased (P<0.01), the writhing reaction score and serum level of PGF2α and PGF2α/PGE2 value were increased (P<0.01), the level of PGE2 was decreased (P<0.01). Compared with the model group, in the EA group and the ibuprofen group the number of writhing were decreased (P<0.05), the latency of writhing was prolonged (P<0.01), the writhing reaction scores and serum levels of PGF2α and PGF2α/PGE2 values were decreased (P<0.05, P<0.01), the levels of PGE2 were increased (P<0.01). Compared with the control group, the protein expression of NLRP3, ASC, caspase-1, GSDMD, GSDMD-N, IL-1ß and IL-18 in the uterine tissues of rats was increased in the model group (P<0.01). Compared with the model group, the protein expression of NLRP3, ASC, caspase-1, GSDMD, GSDMD-N, IL-1ß and IL-18 in the uterine tissues of rats was decreased in the EA group and the ibuprofen group (P<0.01, P<0.05). There was no significant difference between the EA group and the ibuprofen group in the above indexes (P>0.05). CONCLUSION: EA could alleviate pain and uterine tissue injury in rats with PDM. The mechanism may be related to the inhibition of the activation of NLRP3 inflammasome in rat uterine tissues, thereby inhibiting pyroptosis and its inflammatory factors release.

[Effect of electroacupuncture intervention on relieving pain and inflammation by suppressing TLR4/NF-κB signaling in rats with primary dysmenorrhea].

OBJECTIVE: To investigate the mechanism of electroacupuncture(EA) intervention in rats with primary dysmenorrhea(PDM) based on the Toll-like receptor 4(TLR4)/nuclear factor(NF)-κB signaling pathway. METHODS: Forty female SD rats were randomly divided into blank control, model, EA and medication groups, with 10 rats in each group. PDM rat model was established by subcutaneous injection of estradiol benzoate combined with intraperitoneal injection of oxytocin. At the same time of model procedures, EA(50 Hz, dense wave) was applied to "Guanyuan" (CV4) and bilateral "Sanyinjiao" (SP6) of rats in the EA group, with needles retained for 20 min, for 10 consecutive days. Rats in the medication group received ibuprofen(125 mg/100 mL, 0.8 mL) by gavage for 10 consecutive days. At the 11th day, writhing behavior of rats was assessed. Uterine morphology was observed by eyes and uterine pathological changes were observed after HE staining. Content of prostaglandin E2 (PGE2) and prostaglandin F2α (PGF2α) in serum and uterine tissues was detected by ELISA; NF-κB p65 positive expression in nucleus was detected by immunofluorescence; protein expression levels of TLR4, NF-κB p65, p-NF-κB p65 and inflammatory factors interleukin (IL) -1ß and IL-18 were detected by Western blot. RESULTS: After modeling, uterus tissues were congested and edematous, with necrosis of luminal epithelium, severe edema and extensive shedding of endometrium, nuclear pyknosis, fragmentation and disappearance, neutrophils infiltration, and slight expansion of glandular cavity, which was milder in the EA and the medication groups. Compared with the blank control group, writhing times, scores and incubation period, HE pathological scores, PGF2α contents in serum and uterine tissues, ratio of NF-κB p65 positive expression in nucleus, TLR4, NF-κB p65, p-NF-κB p65, IL-1ß and IL-18 protein expression levels in uterine tissues of rats in the model group were all significantly increased(P<0.01), while PGE2 contents in serum and uterine tissues were significantly decreased(P<0.01). Compared with the model group, writhing times and scores, HE pathological scores, PGF2α contents in serum and uterine tissues, ratio of NF-κB p65 positive expression in nucleus, TLR4, NF-κB p65, p-NF-κB p65, IL-1ß and IL-18 protein expression levels in uterine tissues of rats in the EA and medication group were all significantly decreased(P<0.01), while writhing incubation period, PGE2 contents in serum and uterine tissues were significantly increased(P<0.05, P<0.01). CONCLUSION: EA intervention could relieve inflammatory response and pain in PDM rats, which may be related to its effect in reducing TLR4 expression, inhibiting NF-κB activation and down-regulating inflammatory factors levels of IL-1ß and IL-18.

Integrative transcriptomics and proteomics analyses to reveal the therapeutic effect and mechanism of Buxue Yimu Pills in medical-induced incomplete abortion rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Medical abortions using mifepristone and misoprostol have been approved in many countries for early pregnancy loss. Despite its high success rate, this medication regimen can result in incomplete abortion, which is responsible for endometrial damage, prolonged uterine bleeding, abdominal pain, etc. Buxue Yimu Pills (BYP) is a famous Chinese medicine prescription that is widely used in the field of gynecology and obstetrics for treating patients with postpartum complications. However, the therapeutic effect and mechanism of BYP remain to be explored. AIM OF THE STUDY: This study aimed to clarify the therapeutic effect and mechanism of action of BYP in postpartum complications using mifepristone and misoprostol-induced incomplete abortion in rats. MATERIALS AND METHODS: Experimental medical-induced incomplete abortion model rats were constructed using mifepristone and misoprostol, and further treated with saline or BYP by intragastric administration. Detailed information regarding the changes in mRNA and protein levels in the uterine tissues of rats regulated by BYP was illustrated by RNA sequencing (RNA-seq) analysis and quantitative proteomics analysis. The differentially expressed genes and proteins were further subjected to Gene Ontology (GO) and pathway enrichment analyses and further verified using quantitative Real-time PCR (qRT-PCR) analysis and western blot assay. RESULTS: BYP administration markedly alleviated the increase in serum prostaglandin F2α (PGF2α) and expression of PGF2α receptor (PGF2αR) in uterine tissues and inhibited the decrease in serum chorionic gonadotrophin (CG). Compared with the model group, 674 genes were upregulated and 344 genes were downregulated by BYP administration; 108 proteins were upregulated and 48 proteins were downregulated by BYP administration. qRT-PCR analysis of the uterine tissues showed that BYP treatment reversed the variation tendency of genes, including Mmp7, Mmp14, Timp2, Col6a4, Jak2, Wnt7a, and Mylk compared with the model group. Western blot analysis showed that BYP administration affected PKCδ, Collagen VI, MMP7, TIMP2, MLCK, and p-MLC protein levels. CONCLUSION: BYP administration facilitated uterine recovery in medical-induced incomplete abortion rats, and this therapeutic effect involved various targets and biological processes, including the TIMP2/MMP7 and MLCK/p-MLC signaling pathways, etc.

Effects of electroacupuncture on NLRP3 inflammasome and pyroptosis protein GSDMD in uterine tissue in rats with primary dysmenorrhea / 中国针灸

OBJECTIVE@#To observe the effects of electroacupuncture (EA) on NLRP3 inflammasome and its downstream protein gastermin D (GSDMD) in rats with primary dysmenorrhea (PDM), and to explore the potential mechanism of EA on the treatment of PDM.@*METHODS@#Forty healthy female SD rats without pregnancy were randomly divided into a control group, a model group, an EA group and an ibuprofen group, 10 rats in each group. PDM model was prepared by injection of estradiol benzoate and oxytocin. Except the control group, the rats in each group were subcutaneously injected with estradiol benzoate for 10 days, and oxytocin was injected on the 11th day. The rats in the EA group were intervened with EA (dense wave, frequency of 50 Hz) at "Guanyuan" (CV 4) and "Sanyinjiao" (SP 6) at the same time of modeling, once a day, 20 min each time, for 10 consecutive days. The rats in the ibuprofen group were treated with 0.8 mL of ibuprofen by gavage (concentration of ibuprofen solution was 1.25 mg/mL) for 10 consecutive days. After modeling, the writhing reaction was observed. After intervention, the HE staining method was used to observe the histological morphology of uterus and evaluate the pathological damage score of uterus; ELISA method was used to detect the serum levels of prostaglandin E2 (PGE2) and prostaglandin F2α (PGF2α); Western blot method was used to detect the protein expression of NLRP3, apoptosis related spot like protein (ASC), caspase-1, GSDMD, GSDMD-N and inflammatory factors (interleukin [IL]-1β, IL-18) in uterine tissue.@*RESULTS@#In the model group, a large number of vacuolar degeneration and death of endometrial epithelial cells, spiral arterioles congestion in lamina propria and neutrophil infiltration were observed. In the EA group, there was a small amount of vacuolar degeneration and death of endometrial epithelial cells, a small amount of spiral arterioles congestion in the lamina propria, and a small amount of neutrophils infiltration. In the ibuprofen group, there was very small number of degeneration and death of endometrial epithelial cells, and no obvious arterial congestion was found in lamina propria, and neutrophil infiltration was occasionally seen. Compared with the control group, in the model group the number of writhing was increased (P<0.01), the writhing reaction score and serum level of PGF2α and PGF2α/PGE2 value were increased (P<0.01), the level of PGE2 was decreased (P<0.01). Compared with the model group, in the EA group and the ibuprofen group the number of writhing were decreased (P<0.05), the latency of writhing was prolonged (P<0.01), the writhing reaction scores and serum levels of PGF2α and PGF2α/PGE2 values were decreased (P<0.05, P<0.01), the levels of PGE2 were increased (P<0.01). Compared with the control group, the protein expression of NLRP3, ASC, caspase-1, GSDMD, GSDMD-N, IL-1β and IL-18 in the uterine tissues of rats was increased in the model group (P<0.01). Compared with the model group, the protein expression of NLRP3, ASC, caspase-1, GSDMD, GSDMD-N, IL-1β and IL-18 in the uterine tissues of rats was decreased in the EA group and the ibuprofen group (P<0.01, P<0.05). There was no significant difference between the EA group and the ibuprofen group in the above indexes (P>0.05).@*CONCLUSION@#EA could alleviate pain and uterine tissue injury in rats with PDM. The mechanism may be related to the inhibition of the activation of NLRP3 inflammasome in rat uterine tissues, thereby inhibiting pyroptosis and its inflammatory factors release.

Targeted metabolomics combined with network pharmacology to reveal the protective role of luteolin in pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is a progressive disease that significantly endangers human health, where metabolism may drive pathogenesis: a shift from mitochondrial oxidation to glycolysis occurs in diseased pulmonary vessels and the right ventricle. An increase in pulmonary vascular resistance in patients with heart failure with a preserved ejection fraction portends a poor prognosis. Luteolin exists in numerous foods and is marketed as a dietary supplement assisting in many disease treatments. However, little is known about the protective effect of luteolin on metabolism disorders in diseased pulmonary vessels. In this study, we found that luteolin apparently reversed the pulmonary vascular remodeling of PAH rats by inhibiting the abnormal proliferation of pulmonary artery smooth muscle cells (PASMCs). Moreover, network pharmacology and metabolomics results revealed that the arachidonic acid pathway, amino acid pathway and TCA cycle were dysregulated in PAH. A total of 14 differential metabolites were significantly changed during the PAH, including DHA, PGE2, PGD2, LTB4, 12-HETE, 15-HETE, PGF2α, and 8-iso-PGF2α metabolites in the arachidonic acid pathway, and L-asparagine, oxaloacetate, N-acetyl-L-ornithine, butane diacid, ornithine, glutamic acid metabolites in amino acid and TCA pathways. However, treatment with luteolin recovered the LTB4, PGE2, PGD2, 12-HETE, 15-HETE, PGF2α and 8-iso-PGF2α levels close to normal. Meanwhile, we showed that luteolin also downregulated the gene and protein levels of COX 1, 5-LOX, 12-LOX, and 15-LOX in the arachidonic acid pathway. Collectively, this work highlighted the metabolic mechanism of luteolin-protected PAH and showed that luteolin would hold great potential in PAH prevention.

Effect of a combination of altrenogest and double PGF2α administrations on farrowing variation, piglet performance and colostrum IgG.

The variation of gestation length in sows leads to difficulties performing farrowing supervision. The present study was performed to investigate whether oral administration of altrenogest until 112 days of gestation and double administration of PGF2α at 113 days of gestation can synchronise the onset of parturition in sows and minimise deleterious effects on the incidence of stillbirths and colostrum quality. Additionally, the effects of synchronised farrowing on colostrum yield and piglet birth weight, colostrum intake and survival rate of piglets until seven days of postnatal life were also investigated. In total, 193 Landrace x Yorkshire crossbred sows were randomly allocated according to parity number into two groups, i.e. control (n = 95) and treatment (n = 98). The control sows were allowed to farrow naturally. The treatment sows were orally administered 20 mg per day of altrenogest for four days from 109 to 112 days of gestation and were administered PGF2α twice on day 113 of gestation. Individual body weight at birth and 24 h after birth of piglets in all litters were determined in both control (n = 1609) and treatment (n = 1707) groups. Colostrum consumption of all piglets, colostrum yield, colostrum IgG and serum progesterone of sows were determined. On average, the total number of piglets born per litter were 17.0 ± 3.1. The proportion of sows farrowed before 114 days of gestation was higher in the control than the treatment group (8.4% and 2.0%, respectively, P = 0.05) and 92.8% of sows in the treatment group farrowed on day 114 of gestation. The percentage of stillborn piglets per litter did not differ significantly between control and treatment groups (4.5% and 4.6%, respectively). Colostrum yield of sows did not differ between control and treatment groups (5.52 ± 0.13 and 5.28 ± 0.12 kg, respectively, P = 0.174). However, colostrum intake of piglets was lower in the treatment than the control group (354.7 ± 6.6 and 381.2 ± 7.0 g, respectively, P = 0.012). Colostrum IgG was higher in the control than the treatment group (41.2 ± 1.1 and 37.3 mg per ml, P = 0.013). In conclusion, altrenogest treatment from 109 to 112 days and double administrations of PGF2α on day 113 of gestation can control gestation length in sows. No deleterious effects of this protocol on the incidence of stillbirths and sow colostrum yield were detected. However, piglet colostrum intake and colostrum IgG were compromised. Thus, care of newborn piglets in the treatment group should be considered.

Increasing vitamin D levels to improve fertilization rates in cattle.

Recently, interest in supplementing vitamin D (Vit D) to improve aspects of health, mainly in human fertility, has emerged. Still, supplementation of Vit D above the minimum required levels has yet to be explored in cattle despite evidence for Vit D receptors in reproductive tissues. The objective of this study was to establish if a dose-response relationship exists between Vit D exposure and success of in vitro production (IVP) of embryos and, if acute supplementation of Vit D improves pregnancy rates during timed artificial insemination (TAI) of dairy cows. Cumulus-oocyte complexes (COCs) were obtained from ovaries acquired from a local abattoir and cultured in five different IVP treatments from three separate collections (Control, 50, 100, 150, and 200 ng/mL of 1,25(OH)2D3; n = 20-30 COCs/group). In Experiment 2, dairy breed cows (n = 100) were synchronized for TAI with the PresynchOvsynch protocol. Cows received 150,000 IU of Vit D (n = 48) or castor oil as control (n = 53) along with gonadotropin-releasing hormone (GnRH) 24 h before TAI. Serum samples were collected before and 24 h after treatment. A small cohort of cows (n = 4) received the same treatments in two separate cycles and follicular fluid (FF) was collected after 24 h for calcidiol (25OHD) analyses. Increased concentrations of Vit D resulted in decreased rates of maturation of COC (150 and 200 ng/mL vs. control and 50 ng/mL; P = 0.01). Supplementation with 50 ng/mL resulted in greater numbers of early blastocyst and blastocyst stage embryos (P < 0.009). Pregnancy at first breeding did not differ (P = 0.13) between groups, but serum 25OHD increased in treated females after 24 h (P = 0.002). The FF 25OHD levels were reflective of serum levels, however, the observed increase in the treatment cycle (P = 0.04) was parallel to an overall increase in serum 25OHD during the entire second cycle, likely due to increased environmental sunlight exposure (March, control vs. May, treatment). A similar increase in the serum 25OHD in the lactating commercial herd maintained in covered housing was not observed, although experiments were conducted during a similar timeframe. This herd had levels of 25OHD near the low end of sufficiency according to National Research Council (NRC) guidelines. We conclude mild Vitamin D supplementation with concentrations at the higher end of NRC guidelines can improve maturation rates of recovered COCs. However, longer term supplementation may be needed to appreciate any benefits on fertility.

Vitamin D is an important hormone that among other things, contributes to bone health, immunity, and reproduction. Recently, research has linked vitamin D to fertility in other species (primates), and therefore the objectives of the current research were to determine if mild supplementation with Vitamin D impacted fertility in female cattle. A dose-dependent relationship was detected between concentrations of vitamin D and embryo development. The concentration of 50 ng/mL of vitamin D appeared to be beneficial to early embryogenesis. Studies in dairy-breed females indicated serum levels of vitamin D correlated well with intrafollicular levels in the periovulatory follicle. Finally, a fertility trial investigated if a single dose of vitamin D improves fertility when administered before artificial insemination in cattle. There were no detectable benefits to this brief supplementation with vitamin D on measures of fertility in this group. It is concluded supplementation with vitamin D improves embryo development in vitro, but brief supplementation did not impact pregnancy success. Longer-term supplementation with vitamin D may be needed to appreciate any measurable benefits on fertility.

Progesterone supplementation to improve fertility of selected subgroups of lactating cows during the summer and fall.

One major cause of low fertility of cows in the summer is progesterone deficiency. We found that insertion of a controlled intravaginal drug-releasing (CIDR) device containing progesterone after artificial insemination (AI) increases pregnancy per AI (P/AI) in cows with uterine disease and low body condition score after calving. Here, we treated only these two subgroups, during the summer and autumn. Control (n = 191 AI) and treatment (n = 230 AI) cows were inseminated at estrus and the treated group received a CIDR device on day 5 post-AI, for 14 days. Overall analysis of data during the summer and autumn indicated no significant differences between treatment and control groups. Analysis of the summer data only indicated a significant effect of treatment: P/AI was higher in CIDR-treated vs. control groups (34.2% vs. 19.3%; p < .038). Results indicated a 15% increase in P/AI during the summer for CIDR-treated cows in subgroups that had responded positively to the progesterone treatment.

Association of dietary and plasma carotenoids with urinary F2-isoprostanes.

PURPOSE: Carotenoids may protect against chronic diseases including cancer and cardiometabolic disease by mitigating oxidative stress and/or inflammation. We cross-sectionally evaluated associations between carotenoids and biomarkers of oxidative stress or inflammation. METHODS: From 2003 to 2009, the Sister Study enrolled 50,884 breast cancer-free US women aged 35-74. Post-menopausal participants (n = 512) were randomly sampled to measure carotenoids and biomarkers of oxidative stress. Dietary carotenoid consumption was assessed using a validated 110-item Block 1998 food frequency questionnaire; use of ß-carotene-containing supplements was also assessed. Plasma carotenoids were quantified, adjusting for batch. Urinary markers of lipid peroxidation, 8-iso-prostaglandin F2α (8-iso-PGF2α) and its metabolite (8-iso-PGF2α-M) were also measured. Since the biomarker 8-iso-PGF2α can reflect both oxidative stress and inflammation, we used a modeled 8-iso-PGF2α to prostaglandin F2α ratio approach to distinguish effects reflecting oxidative stress versus inflammation. Multivariable linear regression was used to assess the associations of dietary and plasma carotenoids with the estimated biomarker concentrations. RESULTS: Total plasma carotenoids were inversely associated with 8-iso-PGF2α-M concentrations (P for trend across quartiles = 0.009). Inverse trends associations were also seen for α-carotene and ß-carotene. In contrast, lutein/zeaxanthin showed associations with both 8-iso-PGF2α and 8-iso-PGF2α-M concentrations. The inverse association for total carotenoids appeared to be specific for oxidative stress (chemical 8-iso-PGF2α; Phighest vs. lowest quartile = 0.04 and P for trend across quartiles = 0.02). The pattern was similar for α-carotene. However, lutein/zeaxanthin tended to have a stronger association with enzymatic 8-iso-PGF2α, suggesting an additional anti-inflammatory effect. Supplemental ß-carotene was inversely associated with both 8-iso-PGF2α and 8-iso-PGF2α-M concentrations, as well as with both chemical and enzymatic 8-iso-PGF2α. Dietary carotenoids were not associated with either biomarker. CONCLUSION: Plasma carotenoids and supplemental ß-carotene were associated with lower concentrations of 8-iso-PGF2α metabolite. Plasma carotenoids associations may reflect antioxidant effects.

Control of parturition in hyperprolific sows by using altrenogest and double administrations of PGF2α.

The aim of the present study was to develop a protocol to reduce the variation in gestation length and synchronise the onset of parturition in sows by using altrenogest in combination with double administrations of prostaglandin F2alpha (PGF2α). In total, 188 Landrace x Yorkshire crossbred sows with parity numbers 3.1 ± 1.6 were included in the experiment. The sows were classified into two groups: CONTROL (n = 94) and TREATMENT (n = 94). CONTROL sows were allowed to farrow naturally, and TREATMENT sows were orally administered 20 mg/day of altrenogest starting when they entered the farrowing house (107.0 ± 2.0 days) until 113 (TREAT-113, n = 18), 114 (TREAT-114, n = 29) and 115 (TREAT-115, n = 47) days of gestation. The altrenogest-treated sows were administered PGF2α twice 6 h apart at 24 h after the withdrawal of altrenogest. The litters were randomly selected (25 and 26 litters from CONTROL and TREATMENT groups, respectively) to determine individual body weight at birth and at 24 h after birth. Gestation length of sows that farrowed naturally averaged 115.1 days (range 111-118), whereas gestation length of altrenogest-treated sows averaged 115.1-116.3 days (range 114-118). The colostrum yield of sows averaged 4.25 ± 1.19 kg and was not affected by the treatment (P > 0.05). Colostrum IgG in the CONTROL group was higher than in the TREAT-114 and TREAT-115 groups (P < 0.05) but did not differ significantly compared to the TREAT-113 group. The proportion of sows that farrowed during working hours (0700-1700 h) in the TREAT-113 group (72.3%) tended to be higher than in the CONTROL (46.4%, P = 0.053). The interval from the last altrenogest treatment until farrowing in the TREAT-113 group was longer than in the TREAT-114 and TREAT-115 groups (62.8, 40.7 and 34.6 h, respectively, P < 0.05). Similarly, the intervals from the first PGF2α administration to the onset of parturition in the TREAT-113 group (38.8 ± 3.8 h) was longer than TREAT-114 (21.9 ± 3.5 h, P = 0.002) and TREAT-115 (25.5 ± 3.7 h, P = 0.016) groups. However, the incidence of stillbirths in the TREAT-113, TREAT-114 and TREAT-115 groups was higher than in the CONTROL (16.4, 17.2, 11.8 and 5.8%, respectively, P < 0.05). In conclusion, altrenogest supplementation in combination with double administrations of PGF2α can reduce the variation in gestation length and synchronise the onset of parturition in sows. However, its side effects on the incidence of stillbirths should be considered.