急性热应激后小鼠的抗氧化能力和Hsp70基因的表达

Anti-oxidative ability and Hsp70 gene expression in heat-stressed mice

为研究急性热应激后小鼠抗氧化酶活性的变化及其肝脏热休克蛋白70基因(Hsp70)的表达规律,选取5～6周龄健康昆明雄性小鼠56只,平均分成7组(1个对照组和6个急性高温处理组)。6个急性高温处理组小鼠分别为41℃、急性高温处理2 h后再置于25℃环境中0、2、6、12、24、48 h的小鼠。分别测定各处理小鼠的脏器指数、血清和肝脏中抗氧化酶的活性,用RT-PCR方法检测肝脏中Hsp70-1,Hsp70-3基因的表达。结果表明,急性热应激处理后,小鼠脏器指数在48 h内没有明显变化。血清中超氧化物歧化酶(SOD)活性显著升高(P<0.05),其中,0 h组和6 h组显著高于对照组(P<0.05);24 h组和48 h组与对照组的差异无统计学意义(P>0.05)。血清中丙二醛(MDA)含量6 h组最高,显著高于对照组(P<0.05);24 h组与对照组差异无统计学意义(P>0.05)。血清中谷胱甘肽(GSH)含量各应急处理组与对照组差异均无统计学意义(P>0.05)。肝脏SOD活性6 h组和24 h组显著高于对照组(P<0.05),48 h组与对照组的差异无统计学意义(P>0.05)。肝脏MDA含量0 h组最高,极显著高于对照组(P<0.01),6、24、48 h组与对照组的差异无统计学意义(P>0.05)。肝脏GSH含量0 h组最高,极显著高于对照(P<0.01)。Hsp70-1的表达丰度0、2、6、12、24 h组均显著高于对照组和48 h组(P<0.05),48 h组和对照组差异不显著(P>0.05)。Hsp70-3的表达丰度0、2、6、12 h组均显著高于对照组(P<0.01),24 h组、48 h组与对照组的差异均无统计学意义(P>0.05)。急性高温处理可引起小鼠血清和肝脏中SOD活性和MDA含量的升高,以及肝脏中Hsp70的高表达,且不同时间的表达量不同,但其抗氧化酶活性、MDA含量以及Hsp70表达丰度均在热应激后48 h基本恢复正常水平。

To investigate the anti-oxidative ability and Hsp70 gene expression in hyperthermia induced mice, Kunming male mice, 5-6 weeks old, were divided randomly into seven groups, one control group and six experimental groups. Mice in experimental groups were treated with high temperature （41 ℃, 2 h）. Organ index, antioxidant enzyme activities, and Hsp70-1, Hsp70-3 gene expression in liver were determined at 0, 2, 6, 12, 24 and 48 h after heat stress. The results indicated there was no significant difference in organ index and serum GSH between the experimental groups and the control, and SOD and MDA level in serum and liver increased significantly after heat stress （P 〈 0.05）. In serum, SOD levels at 0 h and 6 h were significantly higher than those in the control （P 〈 0.05）, and at 24 h and 48 h, there was no significant difference （P 〉 0.05）; MDA level at 6 h was the highest, which was significantly higher compared with the control （P 〈 0.05）, and at 24 h there was no significant difference （P 〉 0.05）. In liver, SOD activities at 6 and 24h were significantly higher compared to the control （P 〈 0.05）, and there was no significant difference at 48h （P 〉 0.05）; MDA level was the highest at 0 h, which was significantly higher compared with the control （P 〈 0.05）, and there was no significant difference at 6 h （P 〉 0.05）; and GSH level was also the highest at 0 h, which was significantly higher compared with the control （P 〈 0.01）. Gene expression of lisp70-1 at 0, 2, 6, 12 and 24 h were significantly higher than those in the control group （P 〈 0.01）, and no significant difference was detected at 48 h （P 〉 0.05）. Gene expression of Hsp70-3 at 0, 2, 6 and 12 h significantly higher than those in the control group （P〈 0.01）, and no significant difference was detected at 24 and 48h （P 〉 0.05）. In conclusion, acute heat stress resulted in the increased SOD and MDA levels in serum and liver, and the increased expression of lisp70 genes, and all these indexes were almost restored to the control level at 48 h after heat stress.