亚低温对局灶性脑缺血大鼠白细胞介素-6和细胞间黏附分子-1表达的影响

目的 探讨亚低温对局灶性脑缺血大鼠缺血局部细胞间黏附分子-1（ICAM-1）表达和血清白细胞介素-6（IL-6）含量的影响。方法 将30只体重在250～300&#8197;g的雌性SD大鼠随机分为实验组（n=15）和对照组（n=15），采用线栓法阻断大鼠一侧大脑中动脉制作局灶性脑缺血模型.制模成功后，实验组和对照组大鼠分别给予亚低温、常温处理，使其肛温保持在（33±1）℃和（37±0.5）℃。12&#8197;h后，自左室取血，断头取脑，检测缺血区ICAM-1阳性血管数目（免疫组化方法）和血清IL-6含量（免疫放射测定法）。结果 实验组缺血局部ICAM-1的表达明显低于对照组（2.45±1.56）vs（18.27±2.45）个/HP，P<0.01］；对照组血清IL-6含量、神经功能缺陷评分明显高于实验组（184±38）vs（124±41）ng/L），P<0.01；（2.13±0.35）vs（1.48±0.25），P<0.01]。结论 亚低温对脑缺血性损害的神经保护作用可能与降低IL-6含量和减少ICAM-1的表达有关。

Effect of Mild Hypothermia on the Expression of IL-6 and ICAM-1 in Rats with Focal Cerebral lschemia

Objective To investigate the effect of mild hypothermia on the expression of ICAM-1 in the ischemia area and on the serum level of IL-6 concentration after middle cerebral artery occlusion (MCAO) in rats.Methods Thirty female Sprague-Dawley rats weighing 250-300 g were randomly assigned to the experiment group(n=15)and the control group(n=15). The unilateral MCAO models of rats were made by using suture embolism. After successfully making the MCAO models, the experiment group and the control group were treated by mild hypothermia and normothermia, respectively. For the experiment group, temperature was maintained at(33±1) after10 minutes, and for the contrl group, temperature was kept at(37±0.5). Twelve hours after cerebral ischemia, 4ml blood was drawn from left ventricles, then the brain was immediately and carefully extracted in each rat. Immunohistochemistry analysis was used to count the number of ICAM-1 positive microvessel in the ischemia area, and immunoradiometric assay(IRA) was used to analyze the serum level of IL-6. Results The number of ICAM-1 positive microvessel in the ischemia area of brain in the experiment group were significantly less than that in the control group (2.45±1.56)/HP vs (18.27±2.45)/HP, (P<0.01), but the serum IL-6 concentration and the neurological severity score in the control group are obviously higher than in the experiment group(184±38)ng/L vs (124±41) ng/L, P<0.01, (2.13±0.35) vs (1.48±0.25), P<0.01, respectively].Conclusion Mild hypothermia can reduce the serum IL-6 concentration and the ICAM-1 expression in ischemia area after cerebral ischemia. We presume that decreasing the expression of IL-6 and ICAM-1 is one of the neuroprotective mechanism in treating ischemic stroke by using mild hypothermia.