Gasperin Bernardo G, Rovani Monique T, Ferreira Rogério, Ilha Gustavo F, Bordignon Vilceu, Gonçalves Paulo B D, Duggavathi Raj
Laboratory of Animal Reproduction-ReproPEL, Department of Animal Pathology, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil; Department of Animal Science, McGill University, Sainte Anne de Bellevue, Quebec, Canada.
Laboratory of Biotechnology and Animal Reproduction-BioRep, Department of Large Animal Clinics, Federal University of Santa Maria, Santa Maria, Rio Grande do Sul, Brazil.
Theriogenology. 2015 Feb;83(3):353-9. doi: 10.1016/j.theriogenology.2014.09.026. Epub 2014 Sep 28.
Follicle development is coordinated by gonadotropins, steroids, and growth factors, which activate multiple signaling pathways. Phosphorylated-MAPK (pMAPK) level was indicated as an early marker of follicle dominance, whereas phosphorylated STAT3 (pSTAT3) was increased in granulosa cells of hypophysectomized rats. We hypothesized that MAPK3/1 and STAT3 pathways are regulated in granulosa cells during follicle deviation in cattle. Cyclic beef cows were synchronized and ovariectomized to recover the two largest follicles. Follicular diameter did not differ on Day 2 but was significantly greater in dominant follicles (DFs) than that in subordinate follicles (SFs) on Days 3 and 4 of the follicular wave. The elevated abundance of CYP19A1 mRNA expression in granulosa cells of DFs and cleaved caspase 3 in Day-4 SFs further validated our in vivo model. Before deviation, pMAPK3/1 levels were significantly higher in granulosa cells of the future DF. STAT3 mRNA and total protein (tSTAT3) were higher in granulosa cells of SFs collected on Day 4. Furthermore, levels of pSTAT3 were dramatically increased in granulosa cells of Day-4 SFs. In conclusion, pMAPK3/1 was increased in the future DF, but such differential abundance between the DF and SF was not evident after deviation. The higher abundance of pSTAT3 in granulosa cells of SFs after deviation suggests that this pathway may be involved in granulosa cell death and follicular atresia.
卵泡发育由促性腺激素、类固醇和生长因子协调，这些物质激活多种信号通路。磷酸化丝裂原活化蛋白激酶（pMAPK）水平被视为卵泡优势化的早期标志物，而在垂体切除大鼠的颗粒细胞中磷酸化信号转导和转录激活因子3（pSTAT3）增加。我们假设在牛卵泡偏离过程中，颗粒细胞中的丝裂原活化蛋白激酶3/1（MAPK3/1）和信号转导和转录激活因子3（STAT3）通路受到调控。对发情周期的肉牛母牛进行同期发情处理并切除卵巢，以获取两个最大的卵泡。在卵泡波的第2天，卵泡直径没有差异，但在第3天和第4天，优势卵泡（DF）的直径显著大于从属卵泡（SF）。优势卵泡颗粒细胞中细胞色素P450 19A1（CYP19A1）mRNA表达丰度的升高以及第4天从属卵泡中裂解的半胱天冬酶3进一步验证了我们的体内模型。在卵泡偏离之前，未来优势卵泡的颗粒细胞中pMAPK3/1水平显著更高。第4天收集的从属卵泡颗粒细胞中STAT3 mRNA和总蛋白（tSTAT3）更高。此外，第4天从属卵泡的颗粒细胞中pSTAT3水平显著升高。总之，未来优势卵泡中pMAPK3/1增加，但在卵泡偏离后，优势卵泡和从属卵泡之间这种差异丰度并不明显。卵泡偏离后从属卵泡颗粒细胞中pSTAT3丰度更高，表明该通路可能参与颗粒细胞死亡和卵泡闭锁。
