Study on apoptosis of bovine mammary gland in different development stages

The purpose is to explore the regulation of apoptosis at different developmental stages in dairy cow mammary gland.Normal cow mammary gland tissues of different developmental stages were sliced in frozen.TUNEL was used to detect the apoptosis of mammary cell.The results showed that the virgin mammary gland developed slowly,little changes in mammary gland,and at this time,no apoptosis was detected.In pregnancy,mammary gland ductal continued to grow,and apoptosis increased.In initial pregnancy 2m,there were a lot of gland alveolus and simultaneously adipocyte apoptosis began to increase,and appearing a secondary apoptosis peak.In lactation,the structure and function of mammary gland were most complete,no changes in mammary gland structure and apoptosis level was low.In involution,gland alveolus collapsed and a lot of cells were apoptosis.In involution 3d,the apoptosis was highest and then decreased.In involution 30d,the mammary gland was recovered and apoptosis decreased.