PI3K信号通路关键基因在猪卵泡发育中的表达规律

【目的】研究不同时期猪卵巢卵泡发生的形态特征及磷脂酰肌醇3–激酶(Phosphoinositide 3-kinase,PI3K)信号通路关键基因在卵泡发生发育中的作用。【方法】通过HE染色观察12日龄、30日龄、70日龄、20月龄卵泡期及黄体期、48月龄的长大二元母猪卵巢卵泡发育的形态变化,应用实时荧光定量PCR检测PI3K通路关键基因在这些时期的表达规律,并通过Western blot法检测PI3K通路重要的下游效应因子p-rpS6在不同时期猪卵巢的表达情况。【结果】12日龄母猪卵巢皮质边缘有大量的原始卵泡,皮质与髓质交界处可见少量初级卵泡及个别的次级卵泡;30日龄母猪卵巢次级卵泡数量增加;70日龄出现3级卵泡;20月龄卵泡期、黄体期分别有大量成熟卵泡、大体积的黄体;48月龄较难观察到原始卵泡。PI3K通路抑制因子PTEN、TSC1、TSC2与激活因子PDK1、AKT1、mTOR的mRNA均在12日龄表达量最高,70日龄、48月龄表达量次之,30日龄和20月龄表达量最低;下游效应基因rpS6的mRNA 30日龄表达量最高,20和48月龄表达量最低,p-rpS6蛋白在12日龄、20月龄、48月龄母猪卵巢高表达,在30日龄、70日龄中几乎不表达。【结论】PI3K通路关键基因在不同时期母猪卵巢中的表达水平不同,说明该通路参与了猪卵泡的早期发生及卵泡成熟的调控过程。

Expression patterns of PI3K signaling pathway key genes in porcine follicular development

Objective To study the morphological characteristics of pig ovarian follicles at different developmental stages and possible roles of key genes of phosphoinositide 3-kinase (PI3K) signaling pathway in follicular development.Method The morphological changes in follicles of 12-, 30-, 70-day postpartum, 20-month follicular phase, 20-month luteal phase and 48-month luteal phase of landrace×large white sows were observed using HE staining. The expressions of key genes of PI3K pathway in these periods were detected by qRT-PCR. The expression of p-rpS6, a downstream effector, was detected by Western blot assay in porcine ovaries at different stages.Result A large number of primordial follicles were observed at the cortical edges of ovaries for 12-day-old pigs, and a small amount of primary follicles and a few secondary follicles were found at the junction of cortex and medulla. The number of secondary follicles increased in 30-day-old pigs. Tertiary follicles appeared in ovaries of 70-day-old pigs. At 20 months of age, a large number of mature follicles and bulked corpus luteum were found at follicular and luteal phases, respectively. It was difficult to observe primary follicles at 48 months of age. For PI3K pathway, the ovarian mRNA expression of inhibitors PTEN, TSC1, TSC2 and activators PDK1, AKT1, mTOR showed the highest levels at 12 days of age, followed by 70 days and 48 months of ages, and the lowest levels at 30 days and 20 months of ages. The downstream effector gene rpS6 of PI3K pathway exhibited the highest level of ovarian mRNA expression at 30 days of age, and the lowest level at 20 and 48 months of ages, while p-rpS6 protein had higher ovarian expression level at 12 days, 20 and 48 months of ages, and no expression at 30 and 70 days of ages.Conclusion The key genes of PI3K pathway have different expression levels at different developmental stages of porcine ovary, which indicates that the pathway is involved in the processes of porcine follicular generation and maturation.