变构促红细胞生成素对小鼠脑缺血后神经新生和血管新生的影响

目的 探讨一种氨基酸突变后无促红细胞生成能力的变构促红细胞生成素(mEPO)对大脑中动脉闭塞小鼠神经新生和血管新生的作用.方法 将30只成年雄性C57BL/B6小鼠随机分为Sham组、I/R+ Veh组和I/R+ mEPO组,每组10只.制作小鼠大脑中动脉闭塞缺血(MCAO)模型,I/R+mEPO组小鼠在再灌注即刻腹腔注入mEPO(5 000 IU/kg),I/R+ Veh组小鼠在制模后注入等体积的生理盐水.通过BrdU检测细胞增殖情况,采用转棒试验对小鼠神经功能进行评估.在脑缺血后第14天,检测3组小鼠脑组织丢失比例、神经新生及血管新生情况.结果 用mEPO处理后,I/R+mEPO组小鼠脑组织丢失比例(14.62±5.80)％显著低于I/R+ Veh组小鼠(29.81±7.75)％,差异有统计学意义(P＜0.05);I/R+mEPO组小鼠脑缺血后第3,7天神经功能均有明显改善,第7天即恢复到正常水平,差异有统计学意义(P＜0.05);I/R+mEPO组小鼠脑缺血后第14天BrdU+/NeuN+双阳性细胞数量(36.25±10.53)和BrdU+/Laminin+双阳性细胞数量(25.25±6.34)显著高于Sham组小鼠和I/R+ Veh组小鼠,差异有统计学意义(P＜0.05).结论 mEPO促进了小鼠脑缺血周边区神经新生及血管新生,从而减轻脑组织的损伤程度并提高神经功能.这种无促红细胞生成作用的mEPO可能会成为临床脑血管病的治疗药物.

Effects of mutant erythropoietin on neurogenesis and angiogenesis after cerebral ischemia in mice

Objective To investigate the effects of novel nonerythropoietic mutant erythropoietin (mEPO) on neurogenesis and angiogenesis after middle cerebral artery occlusion in mice.Methods Totals of 30 adult male C57BL/B6 mice were randomly divided into Sham group (n =10),I/R+ Veh group (n =10) and I/R+mEPO group (n =10).Mice in I/R+mEPO group and I/R+Veh group were treated with mEPO (5 000 IU/kg) or isovolumetric saline after transient middle cerebral artery occlusion (MCAO).Cell proliferation was detected by bromodeoxyuridine (BrdU),while neurological function was assessed progressively by Rota-rod test.Mice were euthanized 14 days after injury and reperfusion (I/R) for evaluation of brain tissue loss volume,neurogenesis and angiogenesis.Results Proportion of brain tissue loss volume in I/R + mEPO group was significantly lower than I/R + Veh group (14.62 ± 5.80) ％ vs (29.81±7.75) ％,P ＜0.05].Neural function in I/R+mEPO group improved significantly in 3d and 7d after cerebral ischemia and returned to normal after 7 d (P ＜0.05).Numbers of BrdU+/NeuN+ cells (36.25±10.53) and BrdU+/Laminin+ cells (25.25± 6.34) in I/R+mEPO group were significantly higher than Sham group and I/R+Veh group (P ＜ 0.05).Conclusions mEPO can promote focal neurogenesis and angiogenesis,and attenuate ischemia-induced brain injury in mice after MCAO.Therefore nonerythropoietic mutant EPO is a potential drug for ischemic stroke therapy.