Prenatal dexamethasone exposure programs the decreased testosterone synthesis in offspring rats by low level of endogenous glucocorticoids.

Prenatal dexamethasone exposure (PDE) can decrease maternal endogenous glucocorticoid level and induce testicular dysplasia in male offspring rats. In this study we investigated low level endogenous glucocorticoid-mediated testicular dysplasia in PDE offspring and elucidated the intrauterine epigenetic programming mechanisms. Pregnant rats were injected with dexamethasone (0.2 mg·kg-1·d-1, sc) on gestational day (GD) 9-20. The offspring rat blood and testis were collected after euthanasia on GD20, postnatal week (PW) 12 or PW28. We showed that PDE induced abnormal morphology of testis and significantly decreased the expression of testosterone synthesis-related genes as well as testosterone production before and after birth. Meanwhile, serum corticosterone, the expression and histone 3 lysine 14 acetylation (H3K14ac) of testicular insulin-like growth factor 1 (IGF1) were significantly decreased. After the pregnant rats were subjected to chronic stress for 2 weeks (PW10-12), serum corticosterone level was increased in the adult PDE offspring, and the above-mentioned other indicators were also improved. Cultured Leydig cells (TM3) were treated with corticosterone (62.5-500 nM) in vitro. We showed that corticosterone concentration-dependently inhibited glucocorticoid receptor α (GRα) and miR-124-3p expression, increased histone deacetylase 5 (HDAC5) expression, and decreased IGF1 H3K14ac level and the expression of IGF1/steroidogenic acute regulatory protein (StAR), suggesting that corticosterone at lower than physiological level (<500 nM) inhibited testosterone synthesis by reducing H3K14ac and the expression level of IGF1 through GRα/miR-124-3p/HDAC5 pathway. In conclusion, PDE can cause persistent inhibition of testosterone synthesis before and after birth in the offspring rats by low level of endogenous glucocorticoids.

Effects of prenatal caffeine exposure on glucose homeostasis of adult offspring rats.

Epidemiological evidences show that prenatal caffeine exposure (PCE) could induce intrauterine growth retardation (IUGR). The IUGR offspring also present glucose intolerance and type 2 diabetes mellitus after maturity. We have previously demonstrated that PCE induced IUGR and increased susceptibility to adult metabolic syndrome in rats. This study aimed to further investigate the effects of PCE on glucose homeostasis in adult offspring rats. Pregnant rats were administered caffeine (120 mg/kg/day, intragastrically) from gestational days 11 to 20. PCE offspring presented partial catch-up growth pattern after birth, characterizing by the increased body weight gain rates. Meanwhile, PCE had no significant influences on the basal blood glucose and insulin phenotypes of adult offspring but increased the glucose tolerance, glucose-stimulated insulin section and ß cell sensitivity to glucose in female progeny. The insulin sensitivity of both male and female PCE offspring were enhanced accompanied with reduced ß cell fraction and mass. Western blotting results revealed that significant augmentation in protein expression of hepatic insulin signaling elements of PCE females, including insulin receptor (INSR), insulin receptor substrate 1 (IRS-1) and the phosphorylation of serine-threonine protein kinase (Akt), was also potentiated. In conclusion, we demonstrated that PCE reduced the pancreatic ß mass but increased the glucose tolerance in adult offspring rats, especially for females. The adaptive compensatory enhancement of ß cell responsiveness to glucose and elevated insulin sensitivity mainly mediated by upregulated hepatic insulin signaling might coordinately contribute to the increased glucose tolerance.

[Effects of curcumol on liver function and fibrosis in rats of nonalcoholic fatty liver disease and its mechanism].

Objective: To investigate the effects and mechanism of curcumol (CC) on liver function and fibrosis in rats of nonalcoholic fatty liver disease (NAFLD). Methods: The rat models of nonalcoholic steatohepatitis (NASH) combined with liver fibrosis were constructed by high-fat diet. Sixty SD rats were randomly divided into blank control group, model group (NASH), NASH + Compound Biejiarangan Troche (CBT) group (positive control group), and NASH + CC groups (25, 50, 100 mg/kg) , 10 rats in each group. The percentage of liver to body weight, and the levels of high density lipoprotein (HDL), triglyceride (TG), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured. The liver fibrosis was observed by HE staining. The expressions of α-smooth muscle actin (α-SMA) and positive staining of nuclear factor κB p65 (NF-κB p65) were detected by immunohistochemistry. The expression levels of α-SMA, matrix metalloproteinase-1 (MMP-1), tissue inhibitor of metalloproteinase-1 (TIMP-1) and toll-like receptor-4 (TLR4), transforming growth factor-activated kinase-1 (TAK1), NF-κB p65 and vascular cell adhesion molecule-1 (VCAM-1) were detected by Western blot. The expression levels of interleukin (IL-6, IL-10, IL-1ß) and tumor necrosis factor-α (TNF-α) were detected by enzyme linked immunosorbent assay (ELISA). Results: Compared with blank control group, the contents of HDL and IL-10 and the expression level of MMP-1 protein were decreased in model group significantly (P＜0.05), while the levels of TG, ALT and AST, the positive rate of P65, α-SMA, TIMP-1, TLR4, TAK1, NF-κB p65, VCAM-1, IL-6, TNF-α and IL-1ß were increased significantly (P＜0.05). Compared with model group, the levels of HDL, IL-10 and MMP-1 protein were significantly increased after treatment with CBT and CC (P＜0.05), while the levels of TG, ALT, and AST, the positive rate of P65, α-SMA, TIMP-1, TLR4, TAK1, NF-κB p65, VCAM-1, IL-6, TNF-α and IL-1ß were decreased significantly (P＜0.05). The improvement in model+high- concentration CC group was the most significant, and which in all concentration groups was lower than that in model+CBT group (P＜0.05). Conclusion: CC can reduce inflammation response and improve liver function by regulating TLR4, TAK1 and NF-κB/p65 signaling pathway, and thus alleviating liver fibrosis, showing concentration-dependence within certain range.

Reduced testicular steroidogenesis in rat offspring by prenatal nicotine exposure: Epigenetic programming and heritability via nAChR/HDAC4.

Prenatal nicotine exposure (PNE) may lead to offspring's testicular dysplasia. Here, we confirmed the intergenerational effect of PNE on testosterone synthetic function and explored its epigenetic programming mechanism. Pregnant Wistar rats were injected subcutaneously with nicotine (2 mg/kg.d) from gestational day 9-20. Some dams were anesthetized to obtain fetal rats, the rest were allowed to spontaneous labor to generate F1 and F2 generation. In utero, PNE impaired testicular development and testosterone production. Meanwhile, the expression of steroidogenic acute regulatory protein (StAR) and 3ß-hydroxysteroid dehydrogenase (3ß-HSD) were decreased both in F1 and F2 generations. Furthermore, PNE enhanced the expression of fetal testicular nicotinic acetylcholine receptors (nAChRs) and histone deacetylase 4 (HDAC4), while obviously weakened histone 3 lysine 9 acetylation (H3K9ac) level of StAR/3ß-HSD promoter from GD20 to postnatal week 12 and even in F2 generation. In vitro, nicotine increased nAChRs and HDAC4 expression, and decreased the StAR/3ß-HSD H3K9ac level and expression, as well as the testosterone production in Leydig cells. Antagonism of nAChRs and inhibition of HDAC4 reversed the aforementioned changes. In conclusion, PNE programmed testicular low steroidogenesis and its heritability in male offspring rats. The underlying mechanism was associated to the low-level programming of StAR/3ß-HSD H3K9ac via nAChR/HDAC4.

[Progress in individual identification of burned bones].

The burned bone DNA test have became more and more important in identifying the individuals and paternity involved in the fire, explosion disasters as well as burn corpse crimes. As an important genetic marker system, STR has been widely used in forensic individual identification, paternity test and other fields. In this article, the influence of burned temperature and time to STR typing was reviewed, the choice of STR locus and DNA extraction methods were discussed about burned bones.

The GC-IGF1 axis-mediated testicular dysplasia caused by prenatal caffeine exposure.

Prenatal caffeine exposure (PCE) can induce testicular developmental toxicity. Here, we aimed to explore the underlying mechanism of this process in reference to its intrauterine origin. Pregnant rats were intragastrically administrated caffeine (30 and 120 mg/kg/day) from gestational days 9 to 20. The results showed that the male fetuses exposed to high dose of caffeine (120 mg/kg/day) had a decreased bodyweight and inhibited testosterone synthetic function. Meanwhile, their serum corticosterone concentration was elevated and their testicular insulin-like growth factor 1 (Igf1) expression was decreased. Moreover, the histone 3 lysine 14 acetylation (H3K14ac) level in the Igf1 promoter region was reduced. Low-dose (30 mg/kg/day) caffeine exposure, however, increased steroidogenic enzymes expression in male fetuses. After birth, the serum corticosterone concentration gradually decreased in the PCE (120 mg/kg/day) offspring rats, whereas the expression and H3K14ac level of Igf1 gradually increased, with obvious catch-up growth and testicular development compensation. Intriguingly, when we subjected the offspring to 2 weeks of chronic stress to elevate the serum corticosterone concentration, the expression of Igf1 and testosterone synthesis were inhibited again in the PCE (120 mg/kg/day) group, accompanied by a decrease in the H3K14ac level in the Igf1 promoter region. In vitro, corticosterone (rather than caffeine) was proved to inhibit testosterone production in Leydig cells by altering the H3K14ac level and the expression of Igf1. These observations suggested that PCE-induced testicular developmental toxicity is related to the negative regulation of corticosterone on H3K14ac levels and the expression of Igf1.

Prenatal ethanol exposure induces susceptibility to premature ovarian insufficiency.

Prenatal ethanol exposure (PEE) adversely affects the offspring reproductive system. We aimed to confirm the susceptibility to premature ovarian insufficiency (POI) in female PEE offspring and elucidate its intrauterine programming mechanism. The pregnant Wistar female rats were intragastrically administered with 4 g/kg×d of ethanol from gestational day (GD) 9 to 20. Offspring reproductive parameters were detected on GD20, postnatal week (PW) 6, and PW12. The PEE foetuses showed a decreased number of oocytes, increased ovarian cell apoptosis, and upregulated expression levels of ovarian insulin-like growth factor 1 (IGF1) signaling pathway and steroidogenic enzymes. The proportion of atretic follicles in adult rats was increased, while the number of anti-Müllerian hormone-positive antral follicles was decreased. The serum oestradiol (E2) levels were decreased, but the follicle stimulation hormone levels were elevated. The ovarian Igf1 signaling pathway was transformed from activation during puberty to relative inhibition in adulthood, and the expression levels of ovarian steroidogenic enzymes were inhibited in adulthood. Furthermore, we treated the human granulosa cell line KGN with different ethanol concentrations (15, 30, 60, 120 mM) and found that the expression of IGF1 signaling pathway components, 3ß-HSD, and P450arom, as well as the production of E2, was increased. After IGF1 siRNA transfection, P450arom expression and E2 production were downregulated. These results suggest that PEE induces POI susceptibility in adult females, which may be caused by over-activation of the foetal ovarian Igf1 signaling pathway and steroidogenesis under PEE, resulting in accelerated early development of folliculogenesis and depletion of primordial follicles.

Prenatal caffeine exposure induced high susceptibility to metabolic syndrome in adult female offspring rats and its underlying mechanisms.

Our previous studies have demonstrated that prenatal caffeine exposure (PCE) induced an intrauterine programming of hypothalamic-pituitary-adrenal axis (HPAA)-associated neuroendocrine metabolism in 3-month-old offspring rats. In this study, we aimed to confirm this programming disorder and high susceptibility to metabolic syndrome (MS) in 10-month-old female PCE offspring with postnatal catch-up growth. We found that PCE female offspring rats showed decreased bodyweight but a higher rate of weight gain after birth. Moreover, in the offspring, basal hyperinsulinemia and insulin resistance were observed before unpredictable chronic stress (UCS), but serum total cholesterol (TCH) levels and triglyceride/high-density lipoprotein-cholesterol (TG/HDL-C), TCH/HDL-C and low-density lipoprotein-cholesterol/HDL-C (LDL-C/HDL-C) ratio changes were increased after UCS, accompanied by morphological damage of the related tissues. These results suggested that PCE adult female offspring rats were highly susceptible to MS, which is related to HPAA-associated neuroendocrine-metabolic programming disorder.