甘加型藏羊发情周期下丘脑-垂体-卵巢轴中ERβmRNA及其蛋白的表达

Expression of ERβin hypothalamic-pituitary-ovarian axis of Ganjia Tibetan sheep in estrus cycle

为阐明甘加型藏羊(Ovis arise)发情周期下丘脑-垂体-卵巢(hypothalamic-pituitary-ovarian axis,HPO)轴中雌激素受体β(estrogen receptorβ,ERβ)mRNA和蛋白的表达及分布,本试验选取健康且在发情周期内的甘加型藏羊32只,运用qRT-PCR、Western blot技术和免疫组织化学染色法检测甘加型藏羊发情周期ERβmRNA及蛋白在HPO轴中的表达和分布差异。结果显示,甘加型藏羊整个发情周期(发情前期、发情期、发情后期及间情期)ERβmRNA及其蛋白在HPO轴中均有表达和分布。下丘脑中ERβmRNA及其蛋白在下丘脑中发情前期表达最多,显著高于其他3个时期(P<0.05);垂体中ERβmRNA及蛋白均在发情前期表达最高,与其他3个时期差异显著(P<0.05);在卵巢中间情期表达最高,显著高于其他3个时期(P<0.05)。免疫组织化学染色结果显示,ERβ阳性表达主要分布在下丘脑大神经元胞体和轴突中;在垂体中多分布在远侧部及中间部嗜酸性细胞胞浆中,胞核中分布较少;在卵巢中,生长卵泡颗粒细胞胞浆和胞核、卵泡内膜细胞及黄体细胞胞浆中均有分布。ERβmRNA及其蛋白在甘加型藏羊发情周期HPO轴的差异性表达表明雌激素受体β参与调节甘加型藏羊的生殖生理活动。

To evaluate the expression and distribution of estrogen receptorβ(ERβ)in the hypothalamus-pituitary-ovarian(HPO)axis of Ganjia Tibetan sheep in estrum cycle,thirty-two sheep with healthy and non-pregnant Ganjia Tibetan sheep during the estrus cycle were collected from the Tibetan sheep farm.Real-time fluorescent quantitative polymerase,Western blot and immunohistochemical staining were used to detect the expression and distribution of ERβmRNA and its protein in HPO axis of Ganjia Tibetan sheep at different stages of the estrus cycle.The results showed that ERβmRNA and its protein were expressed and distributed in hypothalamus,pituitary and ovary during the whole estrus cycle(proestrus,estrus,metestrus and diestrus)of Ganjia Tibetan sheep.ERβmRNA and its protein were significantly higher in the proestrus as compared with the other three stages(P<0.05)in hypothalamus.It was found that ERβmRNA and protein in proestrus was significantly higher than the other three stages(P<0.05)in pituitary,and the highest expression was found in ovarian tissue in diestrus and significantly higher than the other three stages(P<0.05).The immunohistochemical results reported that the positive expression of ERβwas mainly distributed in large neuronal cytoplasm and axons.The stronger expression was observed in the eosinophilic cytoplasm in distal and intermediate parts of the pituitary,but weaker expression was found in nucleus.In ovary,ERβpositive reaction was distributed in cytoplasm of growth follicular granulosa cells and nuclei,follicular endometrium cells and luteal cells.The different expression of ERβin the HPO axis in the estrus cycle of Ganjia Tibetan sheep suggests that ERβhas important significance for reproductive physiological activities such as the estrus cycle of Tibetan sheep.