抗氧化酶类对大鼠感染性脑损伤的内源性防护作用

Endogenous protective effects of antioxidant enzymes on infectious brain injury in rats

目的通过测定脑组织丙二醛（MDA）、超氧化物歧化酶（CuZn-SOD和Mn－SOD）、过氧化氢酶（CAT）及谷胱甘肽过氧化物酶（GSH－PX）活性的变化，探讨抗氧化酶类在大鼠感染性脑损伤内源性防护机制中的作用。方法向大鼠左颈内动脉注射百日咳杆菌悬浮液（0．2ml／kg体重），诱发感染性脑损伤模型。40只大鼠随机分为生理盐水对照组（NS）和百日咳杆菌悬浮液组（BPS），观察时间为4h和24h（每组10只）。用可见光和紫外分光光度法分别测定MDA、SOD、GSH-PX和CAT的活性。结果BPS4h组MDA、Mn－SOD和CAT活性均高于MS组，CuZn-SOD活性低于NS组，MDA分别与含水量（WC）或伊文思蓝含量（EB）呈显著正相关；BPS24h组Mn-SOD和GSH-PX活性增高，分别与WC、EB及MDA呈显著负相关。结论Mn-SOD和GSH-PX合成的增加在迟发性感染性脑损伤的内源性防护机制中起着重要作用。

Objective We studied the changes of malondialdehyde (MDA), copper/zinc-superoxide dismutase (CuZn-SOD), manganese superoxide dismutase (Mn-SOD), catalase (CAT) and glutathione peroxidase (GSH-PX) activities in cerebral tissues to elucidate protective mechanism of antioxidant enzymes against rat infectious brain injury (IBI). Methods An IBI model was induced by injection of bordetella pertussis suspension (BPS) via the left internal carotid arteries of the rats. Forty rats were randomly divided into 2 groups: group BPS (0.2 ml/kg) was given and in the NS group, normal saline (0.2 ml/kg) was given. The animals were kept under observation for 4 h or 24 h (n=10). The MDA, SOD and GSH-PX or CAT activities were assayed with visible or ultraviolate spectrophotometry, respectively. Results The MDA, Mn-SOD and CAT were significantly elevated and MDA had a positive correlation with the water content (WC) or the Evans blue content (EB) increased in the BPS group for 4 h (r=0.9650, 0.9441, P<0.01), respectively. The CuZn-SOD decreased as compared to the NS treated groupe (P<0.01). The Mn-SOD and GSH-PX were significantly elevated and had a negative correlation with WC or EB or MDA (r:Mn-SOD, -0.8650, -0.9021, -0.9346, P<0.01; GSH-PX, -0.9546, -0.9325, -0.9478, P<0.01) with decrease in the BPS treated group for 24 h. Conclusions It suggests that induction of increased Mn-SOD and GSH-PX activities may play an important role in endogenous protective mechanism against delayed infectious brain injury.