Feng T, Schutz L F, Morrell B C, Perego M C, Spicer L J
Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, China.
Department of Animal Science, Oklahoma State University, Stillwater, OK 74078, USA.
Reprod Fertil Dev. 2018 Mar;30(4):643-650. doi: 10.1071/RD17203.
Melatonin affects granulosa cell function in several species but its function in theca cells is less clear, particularly in monotocous animals. Thus, the objectives of this study were to determine the effects of melatonin on theca cell steroidogenesis, gene expression and cell proliferation in a monotocous species, namely cattle. Ovaries were collected from a local bovine abattoir, from which theca cells were isolated from large (8-22mm) follicles and treated with various hormones in serum-free medium for 24h or 48h. Melatonin caused a dose-dependent inhibition (P<0.05) of LH+insulin-like growth factor 1 (IGF1)-induced androstenedione and progesterone production. Also, melatonin inhibited (P<0.05) LH+IGF1-induced expression of steroidogenic acute regulatory protein (StAR) mRNA (via real-time polymerase chain reaction) in theca cells, but it had no effect (P>0.10) on cytochrome P450 11A1 (CYP11A1) and cytochrome P450 17A1 (CYP17A1) mRNA abundance. In LH+IGF1-treated theca cells, melatonin decreased caspase 3 (CASP3) mRNA to levels similar to those observed in LH-treated theca cells. In contrast, melatonin increased (P<0.05) the number of bovine theca cells in both LH- and LH+IGF1-treated cultures. In conclusion, melatonin may act as an endocrine regulator of ovarian function in cattle by stimulating theca cell proliferation and inhibiting differentiation via inhibition of hormone-induced steroidogenesis.
褪黑素对多种物种的颗粒细胞功能有影响，但其在卵泡膜细胞中的功能尚不清楚，尤其是在单胎动物中。因此，本研究的目的是确定褪黑素对单胎物种（即牛）卵泡膜细胞类固醇生成、基因表达和细胞增殖的影响。从当地一家牛屠宰场收集卵巢，从其中直径为8 - 22毫米的大卵泡中分离出卵泡膜细胞，并在无血清培养基中用各种激素处理24小时或48小时。褪黑素对促黄体生成素（LH）+胰岛素样生长因子1（IGF1）诱导的雄烯二酮和孕酮生成产生剂量依赖性抑制作用（P<0.05）。此外，褪黑素抑制（P<0.05）LH+IGF1诱导的卵泡膜细胞中类固醇生成急性调节蛋白（StAR）mRNA的表达（通过实时聚合酶链反应），但对细胞色素P450 11A1（CYP11A1）和细胞色素P450 17A1（CYP17A1）mRNA丰度没有影响（P>0.10）。在LH+IGF1处理的卵泡膜细胞中，褪黑素将半胱天冬酶3（CASP3）mRNA水平降低至与LH处理的卵泡膜细胞中观察到的水平相似。相比之下，褪黑素增加（P<0.05）了LH处理和LH+IGF1处理培养物中牛卵泡膜细胞的数量。总之，褪黑素可能通过刺激卵泡膜细胞增殖并通过抑制激素诱导的类固醇生成来抑制分化，从而作为牛卵巢功能的内分泌调节因子。
