Study On The Apoptosis And It's Pathway During Placentation In Yaks

In order to clarify and reveal: (1) the model of placentation and the type of placenta in yaks, (2) apoptosis of endometrium and trophoblast cells during placentation in yaks, (3)the expression characteristic of apoptosis associated proteins, such as Fas/FasL, TNFα/TRADD,Bcl-2/Bax,caspase-3,caspase-9 , and to confirm the potential pathway of apoptosis of endometrium and trophoblast cells during the placentation in yaks, several experiments were conducted in this study and corresponding result were gained as following: (1)Reproductive tracts were obtained from 24 pregnancy yaks which were between 28 and 45days of early pregnancy. We observed the changes of uterus endometrium and trophoblast cells by the light microscopy, transmission electron microscopy and scanning microscopy. The results showed that the placentation of yaks begin on 28 day, sign as endometrium epithelium extrude or sink to form a sawtooth structure that interdigitated with trophoblast projections, both side interlocked almost perfectly with each other. During the placentaion, TGC that from trophoblast migrating towards the uterine side and fused with uterine epithelium cells to form BNCs and MNCs of maternal. At day 28, there could see capillary vessel and immature erythrocyte with nucleolus in the trophoblast and on 40 day capillary vessel impressed on the maternal-fetal interface. At day 45 the projection of uterine became remarkabley branched and longer, narrower from this period onward. As showing above, the placenta type of yaks was the epitheliochorial and placentation began at about 28 day. (2) By HE stained and DNA in situ end labeling(Tunel), DAPI and transmission electron microscopy, we find that the characteristic of cell apoptosis included the cell with a single small nucleus with distinctly dense homogeneousely staining chromatin and the cell containing multiple smaller, densely staining nuclear fragment; the second pattern was many apoptotic bodies with different shapes and in DAPI, apoptosic cells characterized by compact and shrinked nuclei with strong and intensive blue fluorescence. Tunel positive cells indicated brown nuclei or intensive green fluorescence. During the placentation, the apoptotic rate of endometrium epithelium rised from 26th and achieved peak on 34th of pregnancy, then decreased in the following days slowly. At the same times, the cell type of apoptotic cells is different during placentation in yaks, in trophoblast were giant cells and in endometrium were epithelium cells and endothelium cells, respectively. Apoptotic cells in stromal were sporadic. (3) The expression of Ki-67 protein was carries out by immunohistochemistry to reveal the cell proliferation during the placentation, result indicated that Ki-67 protein expressed in all stage of uterus epithelia and trophoblast, but the changes pattern in epithelia and trophoblast were different during placentation...