糖尿病大鼠的SOD活性与抗氧化剂治疗对机体抗氧化状态的影响

目的 探究糖尿病大鼠主要脏器SOD活性及蛋白表达水平的变化，并观察抗氧化剂N-乙酰半胱氨酸（N-acetylcysteine，NAC）短期治疗（4周）后对机体抗氧化状态的影响。方法 STZ诱导的糖尿病大鼠（D组，n=8）每天给予NAC 1.5 g/kg灌胃治疗（D+N组，n=8），正常对照组（C组，n=8）同时给予同体积生理盐水。4周后，获取心、肺、肝、肾组织，试剂盒检测血浆总SOD、总抗氧化物浓度、脂质过氧化特异性标志物15-F₂t-isoprostane及各组织总超氧化物歧化酶（superoxide dismutase，SOD）活性，Western blotting分析SOD亚型Cu/Zn-SOD及Mn-SOD蛋白表达水平。结果 与C组相比，D组大鼠血浆15-F2t-isoprostane与总抗氧化物浓度及心肌组织中总SOD活性显著升高，而血浆、肺、肝、肾组织总SOD活性显著降低；心、肺组织中Cu/Zn-SOD蛋白表达水平明显升高，而肝、肾组织中明显降低；肺、肾组织中Mn-SOD蛋白表达水平明显降低，而肝组织明显升高，但心肌组织变化不明显。NAC干预能不同程度逆转上述改变，但进一步降低肾组织Mn-SOD表达。结论 糖尿病大鼠各组织中总SOD活性、Cu/Zn-SOD及Mn-SOD蛋白表达水平具有组织差异性，抗氧化剂NAC能不同程度恢复糖尿病大鼠各组织抗氧化水平，从而起到阻止或延缓糖尿病相关的靶器官功能损害的作用。

Effect of anti-oxidant treatment on the expression and activity of SOD in diabetic rats

Objective To study the changes of total SOD activity and expression in major organs and observe the effects of antioxidant N-acetylcysteine (NAC) on antioxidant status in diabetic rats. Methods Normal rats (group C, n=8) or streptozotocin (STZ)-induced diabetic rats (group D, n=8) were treated with NAC 1.5 g/kg/d (Group D+N, n=8) or equal volume of normal saline once daily by gastric gavage for 4 weeks. Blood samples were collected and the 15-F2t-isoprostane, total antioxidant concentration and SOD activity were assayed. The heart, lung, liver and kidney tissues were collected for assay of the total SOD activity using a kit and the protein expression of SOD isoforms, including Cu/Zn-SOD and Mn-SOD, was determined by western blot.Results The levels of 15-F2t-isoprostane and total antioxidant concentration in plasma, total SOD activity in the heart, protein expression of Cu/Zn-SOD in the heart and lung, and Mn-SOD expression in the liver were significantly increased (PPConclusions The levels of total SOD activity and protein expression of Cu/Zn-SOD and Mn-SOD in diabetic rats are tissue specific, and antioxidant NAC can attenuate the target organ damages to a certain degree by restoring the antioxidant levels in diabetic rats.