褪黑素对SD大鼠脑缺血再灌注损伤后c-fos表达的影响

目的探讨褪黑素在大鼠脑缺血再灌注损伤中的神经保护作用及可能机制。方法选取45只雄性SD大鼠,分为假手术组(5只)、脑缺血再灌注组(20只)、褪黑素干预组(20只);脑缺血再灌注组和褪黑素干预组根据时间点第6小时、第1天、第3天、第7天分为4个组,每组5只。采用Longa线栓法建立大鼠左侧大脑中动脉栓塞(MCAO)模型,采用HE染色检测脑组织的病理改变,TUNEL染色检测神经细胞的凋亡,免疫组织化学(免疫组化)法及蛋白质印迹法(Western Blotting)观察大鼠脑组织内c-fos表达情况。结果在脑缺血再灌注组的各时间点的HE染色显示,胶质细胞呈现程度不一的增生,神经元出现坏死;褪黑素干预能减轻脑缺血再灌注后胶质细胞增生及神经元的坏死。在TUNEL染色凋亡检测中,脑缺血再灌注组各时间点的神经细胞凋亡升高;褪黑素干预组各时间点的细胞凋亡数低于脑缺血再灌注组(P <0.05)。在免疫组化及蛋白质印迹检测中,脑缺血再灌注组c-fos表达增加,在第1天时达到高峰,之后表达逐步降低;在褪黑素干预组,c-fos表达趋势与缺血再灌注组一致,但表达水平比缺血再灌注组相应时间点低,差异有统计学意义(P <0.05)。结论褪黑素能够减轻脑缺血再灌注后神经元的损伤,降低c-fos的表达,表明褪黑素可能通过调控c-fos的表达在脑缺血再灌注中发挥神经保护作用。

Effect of melatonin on c-fos expression after cerebral ischemia/reperfusion injury in Sprague-Dawley rats

Objective To investigate the neuroprotective effect and possible mechanism of melatonin in cerebral ischemia/reperfu?sion injury in rats.Methods A total of 45 male Sprague-Dawley rats were divided into sham-operation group with 5 rats,cerebral ischemia/reperfusion group with 20 rats,and melatonin intervention group with 20 rats.The cerebral ischemia/reperfusion group and the melatonin intervention group were further divided into 6-hour,1-day,3-day,and 7-day groups based on related time points,with 5 rats in each group.The Longa suture method was used to establish a rat model of left middle cerebral artery occlusion(MCAO);HE staining was used to observe the pathological changes of brain tissue;TUNEL staining was used to measure the apoptosis of nerve cells;immunohistochemical staining and Western blotting were used to measure the expression of c-fos in rat brain tissue.Results HE staining showed that at different time points,the cerebral ischemia/reperfusion group had varying degrees of glial cell proliferation and neuron necrosis,and melatonin intervention alleviated glial cell proliferation and neuron necrosis after cerebral ischemia/reperfu?sion.TUNEL staining for cell apoptosis showed that the cerebral ischemia/reperfusion group had a significant increase in the apoptosis of nerve cells at each time point,and the melatonin intervention group had a significantly lower number of apoptotic cells than the cere?bral ischemia/reperfusion group(P<0.05).Immunohistochemical staining and Western blotting showed that the cerebral ischemia/re?perfusion group had an increase in the expression of c-fos,which reached a peak on day 1,followed by a gradual reduction;the mela?tonin intervention group had a similar changing trend of c-fos expression to the cerebral ischemia/reperfusion group,but with a signifi?cantly lower expression level than the cerebral ischemia/reperfusion group at the corresponding time point(P<0.05).Conclusions Melatonin can reduce neuronal damage and c-fos expression after cerebral ischemia/reperfusion,suggesting that melatonin may exert a neuroprotective effect in cerebral ischemia/reperfusion by regulating the expression of c-fos.