促红细胞生成素及其衍生物在局灶性脑缺血中的神经保护作用

目的 探讨氨甲酰促红细胞生成素(CEPO)对缺血性脑损伤的保护作用及机制,并与促红细胞生成素(EPO)进行比较. 方法 用腔内线栓法制造小鼠脑缺血90min再灌注模型,根据颈动脉注射药物的不同分为对照组(注射生理盐水)、EPO 5 μg/kg组、EPO 50 μg/kg组、CEPO 50μg/kg组,每组6只,用脑血流激光多普勒监测脑缺血过程中脑血流的变化;用甲酚紫染色法显示脑梗死区并用imageJ软件计算梗死体积和脑水肿体积;用TUNEL法观察凋亡细胞;用免疫组织化学方法 观察脑缺血再灌注后诱导型一氧化氮合酶(iNOS)的改变. 结果与对照组比较,EPO 50μg/kg组和CEPO 50μg/kg组的脑梗死体积、脑水肿体积、神经功能缺损评分明显减少,差异均有统计学意义(P＜0.05).EPO 50μg/kg组、CEPO 50 μg/kg组缺血皮层iNOS阳性细胞数与对照组比较,差异均有统计学意义(P＜0.05).EPO 50μg/kg组的凋亡细胞[(43.6±10.1)个]、CEPO 50 μg/kg组的凋亡细胞[(40.5±9.8)个]与对照组[(94.2±15.2)个]比较,差异均有统计学意义(P＜0.05). 结论 低剂量的EPO(5μg/kg)无脑保护作用,CEPO 50 μg/kg与较高剂量EPO(50μg/kg)具有相似的增加脑缺血再灌注后的脑血流、减少神经功能缺损评分、减少梗死体积、缩小脑水肿体积和抗细胞凋亡作用,它们通过减少iNOS的表达而发挥神经保护作用.

Neuroprotective effects of erythropoietin and carbamylated erythropoietin on focal cerebral ischemia

Objective To study the neuroprotective effect and the mechanism of carbamylated erythropoietin (CEPO) on ischemic brain injury, and compare it with erythropoietin (EPO). Methods Focal cerebral ischemia/reperfusion models were induced by occlusion of the middle cerebral artery using the intraluminal filament technique. Four groups (control group, EPO 5 μg/kg treatment group, EPO 50μg/kg treatment group and CEPO 50 μg/kg treatment group) were chosen (n=6). The cerebral blood flow was monitored through a Laser-Doppler flow probe. The slices of brain tissue were stained with cresyl-violet and the cerebral volume of infarction and edema was measured by ImageJ software. The apoptotic cells were detected with TUNEL staining. The inducible NO synthase (iNOS) positive cells were observed by immunohistochemistry. Results Compared with the control group, the EPO 50 μg/kg treatment and CEPO 50 μg/kg treatment groups showed significantly decreased infarct and edema volume, and lower scores of national institutes of health stroke scale. The numbers ofiNOS positive cells in the ischemic cortex of the EPO 50 μg/kg treatment and CEPO 50 μg/kg treatment groups were statistically smaller than those of the control group (P＜0.05). The numbers of apoptotic cells in the ischemic cortex ofthe EPO 50 μg/kg treatment and CEPO 50 μg/kg treatment groups ([43.6±10.1] cells,[40.5±9.8] cells) were obviously smaller than those of the control group ([94.2±15.2] cells, P＜0.05).Conclusion Lower dose of EPO (5 μg/kg) has no brain protective effect. Treatment with CEPO 50μg/kg and EPO 50 μg/kg have equal roles in increasing the cerebral blood flow, decreasing the neurological deficit scores and volume of infarct and edema, and boosting the anti-apoptosis by means of inhibiting the expression of iNOS.