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 3β-hydroxysteroid dehydrogenase (3β-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/3β-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/3β-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/3β-HSD H3K9ac via nAChR/HDAC4.

中文翻译：

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产前尼古丁暴露可降低大鼠后代睾丸类固醇生成：通过nAChR / HDAC4进行表观遗传编程和遗传。

产前尼古丁暴露（PNE）可能导致后代的睾丸发育异常。在这里，我们证实了PNE对睾丸激素合成功能的代际影响，并探讨了其表观遗传编程机制。从妊娠第9-20天开始，对怀Wistar大鼠皮下注射烟碱（2 mg / kg.d）。麻醉一些水坝以获得胎鼠，让其余的动物自发产生F1和F2代。在子宫内，PNE会损害睾丸发育和睾丸激素的产生。同时，在F1和F2代中，类固醇生成的急性调节蛋白（StAR）和3β-羟基类固醇脱氢酶（3β-HSD）的表达均降低。此外，PNE增强了胎儿睾丸烟碱型乙酰胆碱受体（nAChRs）和组蛋白脱乙酰基酶4（HDAC4）的表达，而从GD20到出生后第12周甚至在F2代中，明显减弱了StAR /3β-HSD启动子的组蛋白3赖氨酸9乙酰化（H3K9ac）水平。在体外，尼古丁增加了nAChRs和HDAC4的表达，并降低了StAR /3β-HSDH3K9ac的水平和表达，以及Leydig细胞中睾丸激素的产生。nAChRs的拮抗作用和HDAC4的抑制逆转了上述变化。总之，PNE可在雄性后代大鼠体内编程睾丸激素水平低及其遗传性。潜在的机制与通过nAChR / HDAC4对StAR /3β-HSDH3K9ac的低级编程有关。并降低Leydig细胞中StAR /3β-HSDH3K9ac的水平和表达以及睾丸激素的产生。nAChRs的拮抗作用和HDAC4的抑制逆转了上述变化。总之，PNE可在雄性后代大鼠体内编程睾丸激素水平低及其遗传性。潜在的机制与通过nAChR / HDAC4对StAR /3β-HSDH3K9ac的低级编程有关。并降低Leydig细胞中StAR /3β-HSDH3K9ac的水平和表达以及睾丸激素的产生。nAChRs的拮抗作用和HDAC4的抑制逆转了上述变化。总之，PNE可在雄性后代大鼠体内编程睾丸激素水平低及其遗传性。潜在的机制与通过nAChR / HDAC4对StAR /3β-HSDH3K9ac的低级编程有关。