大鼠肾下腹主动脉阻断后再灌注自由基变化对肾功能影响实验研究

Experimental study on the effect of free radical on kidney reper- fusion injury caused by infrarenal abdominal aorta occlusion in rat model

目的探讨大鼠肾下腹主动脉阻断后再灌注自由基变化对肾功能的影响及其作用机制。方法Wistar大鼠42只，随机分为对照组，缺血5h组，缺血5h分别再灌注2、4、8、12h组，每组7只。检测血清尿素氮（BUN）、肌酐（Cr）及血浆和肾组织匀浆丙二醛（MDA）、超氧化物歧化酶（SOD）水平，光镜观察各组大鼠。肾脏及下肢肌肉形态学变化。结果缺血及再灌注组大鼠BUN水平较对照组高，差异有统计学意义（P〈0．05），在I／R 4h组达到最高，随后下降；各组间Cr差异无统计学意义。大鼠血浆MDA水平在对照组与I组，I／R2h组，I／R4 h组，I／R8h组，I／R 12h组组间比较差异有统计学意义（P〈0．05），血浆MDA水平在I／R4h组达到高值，随后下降。大鼠血浆SOD水平在对照组与I／R4h组，UR8h组组间比较差异有统计学意义（P〈0．05）；大鼠肾组织匀浆SOD水平在I／R4h组与对照组，I组，I／R2h组，I／R8h组，I／R12h组组间比较差异有统计学意义（P〈0．05），SOD水平在I／R4h组达到低值，随后升高。光镜观察缺血组肾脏及下肢肌肉组织可见轻度损伤，再灌注组肾脏及下肢肌肉组织损伤程度较缺血组重。结论大鼠肾下腹主动脉阻断后再灌注可造成肾功能异常，与缺血再灌注所激发的自由基合成及释放增多有关。

Objective To study the effect of free radical on kidney reperfusion injury caused by infrarenal abdominal aorta occlusion in rat model and its possible mechanism. Methods Forty-two healthy Wister rats were randomly divided into 6 groups as following （n =7） ： the control group（ sham group） ; simply ischemia 5 h without reperfusion（group I） ; 2 hours reperfusion following ischemia 5 h （I/R 2 h）, 4 hours reperfusion following ischemia 5 h （I/R 4 h） , 8 hours reperfusion following ischemia 5 h（I/R 8 h） and 12 hours reperfusion following ischemia 5 h （I/R 12 h）. In each group the rats were killed to obtain samples of blood and kidney at the specified time points. The contents of BUN, Cr, MDA, SOD in blood and in renal homogenate were measured in each group. We observed the morphological changes of kidney and muscles of lower limb by light microscope. Results BUN level of serum in model group I, I/R 2 h, I/R 4 h, I/R 12 h were higher obviously than those of control group, which were maximal in I/R 4 h, then decreased . MDA level of plasma in model group I, I/R 2 h, I/R 4 h, I/R 8 h, I/R 12 h groups were higher obviously than those of control group, which were maximal in I/R 4 h group, then decreased. SOD level of plasma in model I/R 4 h, I/R 8 h groups were lower obviously than those of control group; SOD level of renal homogenate in model group I, I/R 2 h, I/R 8 h, I/R 12 h groups were higher obviously than those of group I/R 4 h, which were minimal in I/R 4 h group, then increased. By light microscope ： The injury degree of kidney and muscles of lower limb in ischemia group was slight, the injury degree of reperfusion group was severer than ischemia group. Conclusion The kidney reperfnsion injury caused by infrarenal abdominal aorta occlusion in rat model might be concerned with the increase of lipid peroxidation damage after ischemia-reperfusion injury of lower limbs.