热应激奶牛外周血淋巴细胞凋亡相关基因表达及血液学分析

Expression of apoptosis-related genes and blood index in lymphocytes in peripheral blood of dairy cows

用半定量RT- PCR分析日平均气温分别为37 .5°C (高温)、26. 5°C (临界高温) 和5 5°C (对照) 条件下奶牛外周血中HSP70mRNA、HSF1mRNA、Bcl 2mRNA和Bax αmRNA 基因丰度变化规律; 用流式细胞仪分析上述条件下外周血淋巴细胞所处的分裂时期(G0/G1 期, S期及G2/M期) 及淋巴细胞的凋亡率; 用全血自动分析仪分析外周血的血常规。研究发现: (1) 在37. 5°C高温条件下, HSP70mRNA 基因表达水平极显著高于26 .5°C和5 5°C条件下的表达量, 表达水平随温度降低呈下降趋势; HSF1mRNA 表达水平与HSP70mRNA 相反, 随温度降低升高, 5 5°C最高, 相对于其它两个温度条件差异显著; Bcl 2mRNA/Bax αmRNA 在26 5°C时最低, 相对于其它两个温度条件该基因的丰度差异显著; (2) 淋巴细胞凋亡率在26 5°C达到最高峰(10 60%),5 5°C下降至最低(2 7%), 差异显著; (3) 白细胞计数(White blood cell, WBC) (14 75×109/L) 和红细胞计数(Red blood cell, RBC) ( 3 .85×1012/L) 在高温37. 5°C时最低, 随温度下降而逐步上升。RBC 和血红蛋白(Hemoglobin, HGB) 在37. 5°C最低, 随温度降低逐步升高, 相对于其它两个温度差异显著; 红细胞平均血红蛋白含量(Mean corpuscular hemoglobin, MCH) 在26. 5°C最高(18 .

The abundances of HSP70mRNA, HSF1mRNA, Bcl-2mRNA and Bax-αmRNA at different daily mean temperature were determined by relative quantitative RT-PCR. The DNA content, cell phase and the rate of apoptosis of lymphocytes in peripheral blood of dairy cattle at different daily mean temperature were analyzed by FCM. The blood indexes were analyzed by automatic analyzer of blood. The results were showed as follows. (1) The abundance of HSP70mRNA at 37.5°[KG-*9C was extremely higher than those at the other two daily mean temperatures. The expression levels of HSP70mRNA and Bcl-2mRNA declined with the temperature. On the contrary, the abundance of HSF1mRNA at 5.5°[KG-*9C was highest. The ratio of Bcl-2mRNA/Bax-αmRNA was lowest at 26.5°[KG-*9C, significantly different from those at the other two daily mean temperatures. (2) The rate of apoptosis of lymphocytes was 10.60% at 26.5°[KG-*9C, which was the highest among three groups. The rate of apoptosis of lymphocytes was 2.70% at 5.5°[KG-*9C, significantly lower than those in the other two groups. (3) White blood cell (14.75×109/L)and red blood cell ( 3.85×10 12 /L) were lowest at 37.5°[KG-*9C, increasing with the temperature drop. MCH and MCHC were higher than that in the control. It is concluded that these four genes might be attributed to the apoptosis of lymphocytes.