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目的研究神经调节素-1β(NRG-1β)对小鼠脑缺血再灌注后神经行为功能,脑梗死体积,脑组织含水量,神经细胞凋亡以及胶质细胞水通道蛋白-4(AQP-4)表达的影响和神经保护的作用机制。方法应用线栓法建立小鼠大脑中动脉闭塞再灌注(MCAO/R)模型,经颈内动脉微量注射NRG-1β(2μg/kg)干预治疗,Bederson法评价动物的神经行为功能;氯化三苯基四氮唑(TTC)染色,观察脑梗死体积;干湿重法测定脑组织含水量;免疫荧光染色检测神经细胞凋亡;免疫组织化学检测AQP-4的表达。结果脑缺血再灌注损伤后,动物均表现神经行为功能障碍,缺血侧出现脑梗塞病灶,脑组织含水量、神经细胞凋亡数量和胶质细胞AQP-4表达均高于假手术组。与对照组相比较,NRG-1β治疗组缺血24h,动物神经行为功能损伤明显改善,凋亡神经细胞数明显减少,脑梗塞体积显著缩小(P<0.05);但脑组织含水量和AQP-4表达与对照组比较无显著性差异(P>0.05)。缺血再灌注22h、46h和70h组,上述5项指标较相应的对照组均有显著性差异(P<0.05)。结论NRG-1β可能通过下调脑缺血再灌注损伤诱导的胶质细胞AQP-4表达和抑制细胞凋亡,减轻脑水肿和缩小梗死体积,从而改善动物的神经行为功能。
Objective To investigate the effects of neurotensin-1β (NRG-1β) on neurobehavioral function, volume of cerebral infarction, water content in brain tissue and neuronal apoptosis after cerebral ischemia-reperfusion in mice and the effect of AQP- 4) the effect of expression and the mechanism of neuroprotection. Methods The middle cerebral artery occlusion and reperfusion (MCAO / R) model was established by thread occlusion method. The intracranial arterial microinjection NRG-1β (2μg / kg) intervention treatment, Bederson method evaluation of animal neurobehavioral function; Phenylmethyltetrazolium (TTC) staining was used to observe the volume of cerebral infarction. The water content of brain tissue was determined by wet and dry method. Apoptosis of neurons was detected by immunofluorescence staining. The expression of AQP-4 was detected by immunohistochemistry. Results After cerebral ischemia-reperfusion injury, all the animals showed neurobehavioral dysfunction, ischemic lesions with cerebral infarction, water content in brain tissue, the number of apoptotic nerve cells and the expression of AQP-4 in glial cells in sham operation group. Compared with the control group, the neurological deficits in NRG-1β-treated group were significantly improved after 24 hours of ischemia, the number of apoptotic neurons decreased significantly and the volume of cerebral infarction was significantly reduced (P <0.05); however, the water content of brain tissue and AQP- 4 expression compared with the control group no significant difference (P> 0.05). At the 22h, 46h and 70h after ischemia / reperfusion, the above 5 indexes were significantly different from the corresponding control group (P <0.05). Conclusion NRG-1β may improve the neurobehavioral function of the animals by down-regulating the expression of AQP-4, inhibiting the apoptosis of cerebral ischemia-reperfusion injury, decreasing the cerebral edema and infarction volume.