金属硫蛋白对热应激奶牛血淋巴细胞凋亡基因和HSP70基因表达的影响

摘要

Effects of exogenous metallothionein on expression of lymphocyte apoptosis genes and the HSP70 gene of dairy cattle under heat stress were studied with 25 lactating Chinese Holstein cows. They were randomly divided into five groups (A, B, C, D and E, five per group) , and supplemented with 0, 16. 0, 24. 0, 32. 0 and 40. 0 mg Zn-MT, respectively, by intravenous injection. Blood samples were collected at 1st, 7th and 14th day, and the levels of HSP70, Bcl-2, Bax and P53 gene expressions in lymphocytes were measured. The milk yield of the cows in group B was more than those in groups A, C, D and E by 20. 94% (P<0. 05), 15. 83% (P >0.05), 10. 94% (P>0. 05) and 8. 85% (P>0. 05), respectively. The level of HSP70 gene expression in group D was more (P<0. 05) than that in group A, but there were no significant differences (P>0. 05) between groups A and B, C, and E. The levels of Bcl-2 gene expression of groups B, C, D, and E were more than that of the control group (A) , and there was a significant difference (P<0. 05) between groups A and C. The levels of Bax gene expression in groups B and D were lower than that in group A by 22. 00% (P>0. 05) and 13. 00% (P>0. 05) , while the levels of P53 gene expression in groups C and E were lower than that in group A by 22. 00% (P>0. 05) and 34. 00% (P>0. 05) , respectively. Exogenous Zn-MT can improve milk producing ability and regulate the levels of HSP70, Bcl-2, Bax and p53 gene expressions in dairy cattle in a dose-dependent manner.%为探讨金属硫蛋白(MT)对热应激奶牛血淋巴细胞凋亡基因和HSP70基因表达的影响及其机理,选取25头中国荷斯坦奶牛经产泌乳母牛,随机均分为A、B、C、D、E5组,分别按每头0(对照),16.0,24.0,32.0和40.0 mg颈静脉注射Zn-MT,于试验第1(注射Zn-MT之前),7和14天逐头采取血样,测定不同剂量的外源性MT对热应激奶牛血淋巴细胞HSP70、Bcl-2、Bax和p53基因表达水平的影响.结果表明,补给外源性MT后,4个试验组奶牛的产奶性能都有不同程度提高,其中B组奶牛的产奶量比A、C、D和E组分别高出20.94％(P＜0.05),15.83％(P＞0.05),10.94％(P＞0.05)和8.85％(P＞0.05)；各试验组HSP70基因的表达水平都有所上升,其中D组比对照组高出130.00％,达到显著(P＜0.05)水平；各试验组Bcl-2基因的表达水平均高于对照组,其中C组达到显著(P＜0.05)水平；B、D组Bax基因的表达水平和C、E组p53基因的表达水平较对照组分别降低了22.00％,13.00％和22.00％,34.00％,但均未达到显著(P＞0.05)水平.说明外源性MT能改善热应激奶牛的产奶性能并有效调控奶牛血淋巴细胞HSP70、Bcl-2、Bax和p53基因的表达水平,且表现出较为明显的剂量效应.