电针对局灶性脑缺血大鼠缺血区皮层神经生长因子表达的影响

探讨针刺对缺血性脑损伤的保护作用。【方法】SD大鼠36只,随机分为假手术组、缺血模型组和电针组, 每组又分为2周和5周两个时间段组;除假手术组外,其他组均采用热凝闭大鼠大脑中动脉法复制局灶性脑缺血模型,采用免疫组化法观察缺血2周和5周后缺血区皮层神经生长因子(NGF)的变化规律以及针刺对其影响。【结果】两个假手术组大鼠手术侧皮层只见到很少的NGF免疫阳性细胞;两个缺血组大鼠脑缺血区皮层NGF免疫活性细胞的表达与假手术组比较显著增多(P<0．01),缺血5周组与缺血2周组相比缺血区皮层NGF阳性细胞的数量下降(P<0．01);电针组在2周时缺血区皮层NGF免疫阳性细胞的表达增高,与缺血2周组、假手术2周组相比差异具有显著性意义(P<0．01);电针5周组大鼠脑缺血区皮层NGF免疫阳性细胞表达虽呈下降趋势,但仍高于同时间段的缺血组大鼠(P<0．01)。【结论】电针可以增加大鼠脑缺血区皮层NGF的分泌和表达时程,这可能是其保护缺血性脑损伤的机制之一。

Effect of Electroacupuncture on Nerve Growth Factor Expression in Ischemic Cortex of Rats with Focal Cerebral Ischemia

[Objective] To observe the protective effect of acupuncture on ischemic cerebral damage. [Methods] SD rats were randomized into 2-week sham-operation (2W-SO) group (n=6) , 5-week sham-operation (5W-SO) group (n =6) , 2-week cerebral-ischemia (2W-CI) group (n-6) , 5-week cerebral-ischemia (5W-CI) group ( n = 6), 2W-CI electroacupuncture (EA) group (n=6) and 5W-CI EA group (n=6) . Except the sham-operation groups, cerebral ischemia was induced by heat-occlusion of middle cerebral artery in other groups. Changes of nerve growth factor (NGF) expression were monitored in ischemic cortex of rats with 2-week and 5-week ischemia by immunohistochemical method, and the effect of electroacupuncture (EA) was observed. [Results] Few NGF-positive cells were found in the ischemic cortex of sham-operation groups and the expression of NGF were obvious in cerebral ischemia groups as compared with the sham-operation groups ( P < 0.01) . The number of NGF-positive cells decreased in 5W-CI group as compared with that in 2W-CI group (P < 0.01). NGF expression increased in 2 W-CI E A group, the difference being significant as compared with those in 2W-SO group and 2W-CI group (P < 0.01); NGF expression was decreasing in 5W-CI EA group and was still obvious as compared with that in 5W-CI group (P < 0.01) . [Conclusion] EA can increase the secretion and expression period of NGF in rats ischemic cortex, and this may be one of its protective mechanisms for ischemic cerebral damage.