金属硫蛋白对热应激奶牛血淋巴细胞周期、凋亡率及亚型分布的影响

he effect of exogenous metallothionein on lymphocytes in peripheral blood of dairy cattle was conducted with 20 lactating Chinese Holstein cows, which were randomly divided into four groups (A, B, C and D), and supplemented with 0, 4.0, 8.0 and 12.0 mg Zn-MT, respectively, by intravenous injection. Blood samples were collected at 1st, 16th, 31st, 46th and 61st day, and the dynamic changes of cell cycle, apoptosis rate and subsets distribution of lymphocytes were determined. The apoptosis rate of lymphocytes in group B and C were lower than those in group A by 26.63%(P＞0.05) and 24.84%(P＞0.05), respectively. The number of lymphocytes at G0/G1 phage in experimental groups were increased and the number of lymphocytes at S and G2/M phages were tend to decrease, but there were no significant differences(P＞0.05). The number of CD3+ in three trial groups were greater than those in group A by 7.02%(P＞0.05), 5.45%(P＞0.05) and 3.85%(P＞0.05), while the number of CD4+ in experimental groups were higher than those in control group by 31.04%(P＜0.05), 35.68%(P＜0.05) and 39.34%(P＜0.05), respectively. The number of CD8+ and the levels of CD4+/CD8+ in trial groups were increased observably, but significant differences(P＜0.05) was observed in the levels of CD4+/CD8+ between group A and C only. Exogenous Zn-MT can decrease apoptosis rate, improve cell cycle and regulate subsets distribution in dairy cattle in a dose-dependent manner.