rhEPO通过调节JAK2/STAT5信号通路减少大鼠脑出血后神经细胞凋亡

rhEPO reduces neuron apoptosis after intracerebral hemorrhage in rats by regulating JAK2/STAT5 signaling

目的探讨重组人促红细胞生成素rhEPO是否通过JAK2/STAT5信号通路减少脑出血后神经细胞的凋亡。方法将8周龄的Wistar雄性大鼠30只随机分3组:假手术组、ICH模型组、rhEPO组,每组10只。ICH模型组大鼠进行ICH造模,假手术组除不注血外,其余步骤同ICH模型组,rhEPO组术后5 min给予腹腔注射rhEPO,所有动物24 h后进行神经功能学评分,收集大鼠脑组织,利用原位缺口末端标记法检测神经细胞凋亡的变化;采用免疫组织化学SP法检测凋亡蛋白Caspase3表达;并采用Real-time PCR和Western blot检测磷酸化JAK2、磷酸化STAT5基因和蛋白表达情况。结果手术建立脑出血模型后24 h进行神经功能评分。按Longa5分制标准判定,ICH组4只评价为1分,3只评价为2分,2只评价为3分;rhEPO组治疗后,5只评价为1分,2只评价为2分,1只评价为3分,说明rhEPO可以改善大鼠脑出血后神经元损伤,恢复神经功能。与假手术组相比,ICH模型组和rhEPO组中神经元凋亡细胞及Caspase3的蛋白表达阳性细胞数明显增多(P<0.05),而rhEPO组中凋亡细胞与ICH模型组相比明显减少(P<0.05);与假手术组相比,ICH模型组和rhEPO组中JAK2和STAT5的蛋白表达和m RNA表达显著上升(P<0.05),与ICH模型组相比,rhEPO组中JAK2和STAT5的蛋白表达和m RNA表达显著降低,差异均有统计学意义(P<0.05)。结论外源性rhEPO可以通过调节JAK2/STAT5信号改善大鼠脑出血后神经元损伤,对于神经系统具有保护作用。

Objective To investigate whether recombinant human erythropoietin （rhEPO） could decrease neuron apopto- sis after cerebral hemorrhage by regulating JAK2/STAT5 signaling pathway.Methods 30 Wistar male rats of 8 weeks old were randomly divided into 3 groups：sham operation group,ICH model group and rhEPO group,the rats in ICH mod- el group were treated with ICH.In the sham operation group,the treatment were same as ICH group except blood injec- tion.rhEPO group was injected with rhEPO at 5 rain after operation.All animals were scored with neurological score at 24 h after the ICH model was established.The effect of neuronal apoptosis were detected by TUNEL staining.The ex- pression of pro-apoptosis protein Caspase3 was detected by immunohistochemistry.The expressions of JAK2 and STAT5 mRNA and protein were measured by Real time PCR and Western blot.Results Neurological score was performed 24 hours after the establishment of the intracerebral hemorrhage model.According to the criteria of Longa5 standard,in ICH group,four rats were evaluated as score 1,three rats were rated as score 2 and two rats were rated as score 3.In rhEPO group,five rats were evaluated as score 1 and two rats were rated as score 2,one rat were rated at score 3,indicating that rhEPO can ameliorate neuronal damage and restore nerve function after intracerebral hemorrhage in rats.Compared tosham group,the quantity of apoptotic cells and the ex- pression of Caspase3 in ICH model group and rhEPOgroup were significantly increased （P〈0.05）,while the apoptotic cells in rhEPO group were significantly down-regulation compared with the ICH group （P〈0.05）.Compared with the sham group,the protein expression and mRNA expression of JAK2 and STAT5 in ICH group and rhEPO group were significantly up-regulated （P〈0.05）,while the protein expres- sion and mRNA expression of JAK2 and STATS in rhEPO group were decreased significantly compared to ICH group （P〈0.05）.Conelusion rhEPO reduce neuronal apoptosis by regulating JAK2/STAT5 signal after cerebral hemorrhage,and has protective effect on the nervous system in rats.