间歇低氧导致大鼠肾脏损伤以及依达拉奉的干预作用

Kidney injury caused by intermittent hypoxia and intervention effect of edaravone in rats

目的探讨间歇低氧对大鼠肾脏损伤的机制,以及依达拉奉的干预作用和可能的机制。方法将清洁级雄性Wistar大鼠80只随机分为正常对照组(NC组)、间歇低氧组(IH组)、间歇低氧+依达拉奉组(IH+NE组)和间歇低氧+生理盐水组(IH+NS组)。在造模4周后,测定血尿素氮、肌酐水平,光镜及透射电镜下观察肾组织结构变化,免疫组织化学法观察肾损伤分子1(KIM-1)蛋白表达情况,化学法测定丙二醛(MDA)含量、超氧化物歧化酶(SOD)活力以及抑制羟自由基能力,聚合酶链反应检测肾组织中Bcl-2、Caspase-3、Bax在mRNA水平上的表达。结果各组大鼠血尿素氮未见明显差异;与NC组比较,IH组、IH+NS组血肌酐显著升高,经依达拉奉干预后显著降低。光镜及电镜下观察NC组未见明显病理损害,IH组可见肾小管不同程度的损害,经依达拉奉干预后肾小管损害程度减轻。与NC组比较,IH组、IH+NS组KIM-1蛋白平均灰度值显著升高(P<0.01),经依达拉奉干预后KIM-1蛋白平均灰度值降低(P<0.01)。与NC组比较,IH组、IH+NS组SOD活力显著降低,MDA含量和羟自由基含量升高,Bcl-2 mRNA表达减少,Caspase-3和Bax mRNA表达增多,Bcl-2/Bax比值降低,经依达拉奉干预后SOD活力显著升高,MDA含量和羟自由基含量均显著降低,Bcl-2 mRNA表达明显上调,Caspase-3和Bax mRNA表达明显下调,Bcl-2/Bax比值升高。结论间歇低氧可通过氧化应激和调控Bcl-2、Caspase-3、Bax导致肾脏损伤。KIM-1可作为评估肾脏早期损伤的标志物。依达拉奉可能通过清除氧自由基、提高抗氧化能力、调控Bcl-2/Bax及Caspase-3介导的细胞凋亡,从而抵抗间歇低氧所致肾脏损伤。

Objective To investigate the mechanism of the early kidney injury in rats caused by intermittent hypoxia, and investigate the intervention effect of edaravone. Methods Eighty male Wistar rats were randomly divided into a control group(NC), an intermittent hypoxia group(IH), an intermittent hypoxia edaravone treatment group(IH+NE), and an intermittent hypoxia normal saline matched group(IH+NS). After 4 weeks of model establishment,serum urea nitrogen and creatinine concentration were determined. Pathological changes of kidney were observed under light microscope, and ultrastructural changes of glomeruli and renal tubules were observed under electron microscope.The kidney injury molecule 1(KIM-1) protein was detected by immunohistochemistry. The levels of superoxide dismutase(SOD), malondialdehyde(MDA), hydroxyl radical and Bcl-2 mRNA, Caspase-3 mRNA, Bax mRNA in homogenate of kidney tissue were measured. Results Serum urea nitrogen in each group showed no significant difference. Serum creatinine increased significantly in IH group and significantly decreased after edaravone treatment.There were no significant pathological damages in NC group under light and electron microscopy. IH group showed varying degrees of renal tubule damages compared with NC group. Compared with NC group, the mean optical density of KIM-1 protein in IH group and IH + NS group significantly increased(P<0.01), and the mean optical density of KIM-1 protein in IH+NE group significantly decreased(P<0.01). Compared with NC group, the activity of SOD in IH group and IH+NS group significantly decreased, the content of MDA and hydroxyl radical increased, the expression of Bcl-2 mRNA decreased, the expression of Caspase-3 mRNA and Bax mRNA increased, Bcl-2/Bax decreased. After edaravone intervention, the activity of SOD in kidney tissue of rats significantly increased, the content of MDA and hydroxyl radical significantly decreased, the expression of Bcl-2 mRNA increased, the expression of Caspase-3 mRNA and Bax mRNA decreased, Bcl-2/Bax increased. Conclusions Intermittent hypoxia can cause kidney injury through oxidative stress and regulation of Bcl-2, Bax and Caspase-3. KIM-1 may be used as a sensitive indicator for monitoring early kidney injury. Edaravone can prevent kidney injury induced by intermittent hypoxia though scavenging oxygen free radical,improving antioxidant capacity, regulating cell apoptosis mediated by regulating Bcl-2/Bax and Caspase-3.