[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.

[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.

[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.

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.