米诺环素对局灶性脑缺血大鼠脑可塑性的影响

Effects of Minocycline on the Neuronal Plasticity in Rats after Focal Cerebral Ischemia Reperfusion Injury

目的观察米诺环素对大鼠脑缺血再灌注(I/R)损伤后皮质神经元结构及突触素(synaptophysin,SYN)蛋白表达的影响。方法将36只大鼠随机分为假手术组(Sham组)、I/R模型组(I/R组)及米诺环素组(Min组),每组12只。Sham组不进行I/R处理,不给药。I/R组及Min组均采用线栓法阻塞大脑中动脉制作大鼠MCAO模型,再尾静脉注射PBS或米诺环素(3mg/kg,2次/d)14d后,采用Montoya楼梯实验评估3组大鼠前肢运动功能,HE染色观察皮质神经元的形态结构,免疫荧光法观察缺血灶周围神经突的生长,Western blot法检测缺血脑组织内SYN蛋白的表达。结果假手术组大鼠无明显神经功能缺损,皮层神经元细胞形态正常,微管相关蛋白-2(microtubule-associated protein-2,MAP-2)阳性神经元排列整齐,神经突较长;同模型组相比,米诺环素组大鼠的前肢运动功能改善,MAP-2及SYN蛋白表达增加,两组差异有统计学意义(P<0.05)。结论米诺环素能促进大鼠缺血皮层神经元神经突的生长、突触素的表达及神经功能的恢复,发挥对脑组织可塑性的调节作用。

Objective To observe the effects of minocycline on morphology and the expression of synaptophysin in cortical tissues of rats after cerebral ischemia reperfusion injury.Methods 36 male SD rats were randomly divided into 3groups：sham group,model group 〔ischemia reperfusion（I/R）〕and minocycline（Min）group（treated with minocycline for 14 d,3 mg/kg,2times/d）.Middle cerebral artery occlusion（MCAO）was used to established as focal cerebral I/R model.At 14 dafter I/R.Neurological functional recovery was evaluated using the staircase test,the cell morphology in cortex was evaluated by HE staining,the neurite growth was observed by immunostaining with anti-microtubule-associated protein-2（MAP-2）antibody,the expression of synaptophysin in peri-infarct region was tested by Western blot.Results In the sham group,the rats did not show any neurological deficits.The neurons in the cortex were arranged in neat rows and the morphology were normal,the MAP-2positive neurons showed longer neuronal processes than the model group.Compared to the model group,minocycline significantly improved forelimb motor function,increased the expression of synaptophysin and the number of MAP-2-positive cells in peri-infarct region（P〈0.05）.Conclusion Minocycline could improve the neurite regrowth and the expression of synaptophysin of neuron in ischemic cortex,promote neurological functional recovery of rats after MCAO,which is related to regulate the neuronal plasticity.