Histological And Morphological Characteristics Of Ovaries And Expression And Distribution Of Related Factors At Different Ovarian Phases In Tibetan Sheep

The morphological characteristics and related factors expression and distribution of Tibetan sheep ovaries had important effects on the normal functioning of ovary and the process of follicle recruitment,selection and dominance.There were few reports on the histological change of follicles and corpus luteum and VEGF,TGF-β₁,and HIF-1αof Tibetan sheep in ovarian development.Therefore,it was of great significance to study the biological effects of ovarian structural characteristics,their physiological effected and related factors on follicle development and corpora luteum formation.Based on routine tissue sections,HE staining and transmission electron microscopy,the characteristics of ovarian follicles and corpus luteum of Tibetan sheep were observed and analyzed.Quantitative real-time PCR and Western blotting method detected HIF-1α,VEGF,and TGF-β₁at the differential expression of m RNA and protein in ovaries and follicles of different sizes in adult Tibetan sheep.Combined IHC methods was investigated the distribution of protein in ovaries and follicles of different sizes.We wanted to investigate the biological function of tissue structure and related regulators in ovaries and follicles of different sizes in Tibetan sheep.The results showed that:1.Most follicles in the ovary were atresia through granulosa cell atrophy and fibrosis,and the structural characteristics of the mesangial luteal cells and granulosa luteal cells were obvious and the boundaries were clear.Its internal distribution was rich in capillaries.2.With the development of follicles,the shape of follicular cells changes from ellipse to polygon,the number of follicular cells increases and was surrounded by membrane cells,the number and species of organelles also increase and the relationship between them were close,and the secreted cortical granules can be seen in the cytoplasm.3.The ovarian weight of Tibetan sheep during gestation phase was significantly higher than that in follicular and luteal phases（P<0.05）,and the length,width and thickness of ovary were significantly different between the three phases（P<0.05）.The ovarian morphology of the three phases was basically the same,but the follicular phase was mainly dominated by follicular development,while the luteal phase and gestation phase were mainly dynamic development and changes of the luteal.4.The relative expression of VEGF and HIF-1αin gestation phase was significantly higher than that in follicular phase and luteal phase（P<0.05）,TGF-β₁in follicular phase was significantly higher than that in luteal phase and gestation phase.The expression of protein was consistent with the trend of m RNA expression.VEGF,TGF-β₁,and HIF-1αproteins were mainly localized in the theca folliculi interna,granulosa luteal cells and membranous luteal cells.5.VEGF,TGF-β₁,and HIF-1αprotein and m RNA levels were expressed in medium follicles of the relative expression of was significantly higher than that of large follicles and small follicles（P<0.05）,VEGF and HIF-1αfollicles expression trend was consistent,while expression in large follicles was significantly higher than in small follicles（P<0.05）,the three proteins was mainly distributed in theca folliculi interna and granulosa cells.The results showed that the morphological characteristics of Tibetan sheep ovarian tissue could ensure the normal functioning of its function.VEGF and HIF-1αcould play a regulatory role in the maintenance of pregnancy luteal body by regulating the proliferation of granulosa luteal cells and adenohuang cells.TGF-β₁was likely to participate in the proliferation and functional maintenance of granulosa cells and theca folliculi interna and regulate follicle growth and development.Therefore,it was speculated that VEGF,TGF-β₁,and HIF-1αwere mainly involved in the proliferation and differentiation of granulosa cells and theca folliculi interna,especially played a regulatory role in the growth and development of selected follicles（medium follicles）.