Melatonin, which is synthesized in the pineal gland and peripheral reproductive organs, has antioxidant properties and regulates physiological processes. It is well known that melatonin affects in vitro maturation (IVM) of oocytes and embryonic development in many species. However, beneficial effects of melatonin on IVM have been explained mainly by indirect antioxidant effects and little information is available on the underlying mechanism by which melatonin directly acts on porcine cumulus oocyte complexes (COCs). Sonic hedgehog (Shh) signaling is important for follicle development, oocyte maturation, and embryo development, and there may be a relationship between melatonin and Shh signaling. To examine this, we designed three groups: (i) control, (ii) melatonin (10⁻⁹ mol/L), and (iii) melatonin with cyclopamine (2 μmol/L; Shh signaling inhibitor). The aim of this study was to investigate the effects of these agents on cumulus expansion, oocyte maturation, embryo development after parthenogenetic activation (PA), gene expression in cumulus cells, oocytes and blastocysts, and protein expression in COCs. Melatonin significantly increased the proportion of COCs exhibiting complete cumulus expansion (degree 4), PA blastocyst formation rates, and total cell numbers, which were inhibited by addition of cyclopamine. Simultaneously, the expression of cumulus expansion‐related genes (Ptgs1, Ptgs2, and Has2) and Shh signaling‐related genes (Shh, Pthc1, Smo, and Gli1) and proteins (Ptch1, Smo, and Gli1) in cumulus cells was upregulated in the melatonin‐treated group, and these effects were also inhibited by cyclopamine. In conclusion, our results suggest that Shh signaling mediates effects of melatonin to improve porcine cumulus expansion and subsequent embryo development.

中文翻译：

---

褪黑素影响猪卵丘卵母细胞复合物中的声波刺猬信号通路

褪黑激素是在松果体和周围生殖器官中合成的，具有抗氧化特性并调节生理过程。众所周知，褪黑激素会影响卵母细胞的体外成熟（IVM）和许多物种的胚胎发育。但是，褪黑激素对IVM的有益作用主要是通过间接抗氧化剂作用来解释的，关于褪黑激素直接作用于猪卵丘卵母细胞复合物（COC）的潜在机制的信息很少。声波刺猬（Shh）信号对于卵泡发育，卵母细胞成熟和胚胎发育很重要，褪黑激素和Shh信号之间可能存在关系。为了对此进行研究，我们设计了三组：（i）对照，（ii）褪黑激素（10 ^-9 mol / L）和（iii）褪黑素与环巴胺（2μmol/ L； Shh信号抑制剂）。这项研究的目的是调查这些药物对卵丘扩张，卵母细胞成熟，孤雌激活（PA）后胚胎发育，卵丘细胞，卵母细胞和胚泡中的基因表达以及COC中蛋白质表达的影响。褪黑素显着增加了COC的比例，这些COC表现出完全的卵丘扩张（4级），PA胚泡形成速率和总细胞数，这些都被添加环巴胺抑制了。同时，累积扩展相关基因（Ptgs1，Ptgs2和Has2）和Shh信号相关基因（Shh，Pthc1，Smo，褪黑素治疗组的卵丘细胞中的蛋白质（Ptch1，Smo和Gli1和Gli1）和蛋白质被上调，并且这些作用也被环巴胺抑制。总之，我们的结果表明，Shh信号传导介导褪黑激素的作用，以改善猪的卵丘扩展和随后的胚胎发育。