氧化应激在中暑大鼠急性肝损伤中的作用及机制研究

The role of oxidative stress in the acute liver injury of rats with heat stroke and its mechanism

目的探讨氧化应激在中暑急性肝损伤发生中的作用及其可能机制。方法 32只大鼠按随机数字表法分为4组:假加热正常对照组(Sham组)、中暑组(HS组)、假加热N-乙酰半胱氨酸治疗组(Sham-NAC组)以及中暑NAC治疗组(HS-NAC组),每组8只。通过人工气候舱制备中暑大鼠模型,监测大鼠直肠温度(Tr)、脉率(HR)、收缩压(SBP)。记录中暑发生的时间。于中暑开始后12h处死大鼠,测定大鼠血清丙氨酸氨基转移酶(ALT)和总胆红素(TBIL)水平,以及肝脏组织匀浆IL-6、IL-1β、TNF-α、丙二醛(MDA)、总超氧化物歧化酶(T-SOD)和谷胱甘肽(GSH)等指标的变化,组织学观察肝脏氧自由基(ROS)含量、中性粒细胞浸润以及病理损伤情况。结果中暑发生时HS-NAC组与HS组Tr、HR、SBP、中暑发生时间等比较差异无统计学意义(P>0.05),但HS-NAC组的生存时间与HS组相比明显延长,差异有统计学意义(P=0.039)。中暑发生后12h,HS组肝组织匀浆中ROS和MDA含量及血清ALT和TBIL水平较其他3组明显升高(P=0.000),肝组织匀浆中T-SOD和GSH含量较其他3组明显下降(P=0.000)。病理观察显示HS-NAC组肝损伤较HS组减轻(P=0.000)。HS组肝脏中性粒细胞浸润水平及IL-6、IL-1β、TNF-α浓度均明显高于HS-NAC组(P=0.000)。结论氧化应激在中暑肝损伤中起重要作用,其机制可能与直接细胞毒和介导炎症反应有关。

Objective To investigate the role of oxidative stress in acute liver injury in a heat stroke model of conscious rats, and to explore its underlying mechanism. Methods Thirty-two rats were randomly （by using a random number table） assigned into a sham-heated control group （Sham group, n=8）, a sham-heated group treated with NAC （Sham-NAC group, n=8）, a heat stroke group （HS group, n=8） and a heat stoke group treated with NAC （HS-NAC, n=8）. Rats were prepared with pre-warm chamber to initiate heat stoke. The change of rectum temperature （Tr）, heart rate （HR） and systolic blood pressure （SBP） were monitored, and the time point of HS onset was recorded. Rats were sacrificed 12h after HS onset. ALT, serum TBIL, IL-6, IL-1β, TNF-α, MDA, T-SOD and GSH in the liver homogenates were measured. Liver tissues were harvested for determining the concentration of reactive oxygen species （ROS）, neutrophil infiltration and the histological changes. Results During HS onset, no significant differences were observed in Tr, HR, SBP and heat exposure time between HS group and HS-NAC group （P〉0.05）. However, the survival time was significantly longer in HS-NAC group than in HS group （P=0.039）. 12 hours after HS onset, the concentrations of ROS and MDA in the liver homogenates were significantly higher in HS group than in the other groups （P=0.000）, while the concentrations of T-SOD and GSH were much lower than in the other groups （P=0.000）. The serum concentrations of ALT and TBIL weresignificantly higher in HS group than in the other groups （P=0.000）. Compare with HS group, the pathological injury was alleviated in HS-NAC group （P=0.000）. The neutrophil infiltration level and the concentrations of IL-6, IL-1β and TNF-α in liver tissue were significantly higher in HS group than in HS-NAC group （P=0.000）. Conclusion Oxidative stress may play an important role in the pathogenesis of HS liver injury through its cytotoxic effect and by inducing inflammatory responses.