重组人促红细胞生成素对新生鼠脑室周围白质软化的影响及其机制

Effect and mechanism of recombinant human erythropoietin on periventricular leukomalacia in newborn rats

目的观察重组人促红细胞生成素(rEPO)对新生鼠脑室周围白质软化(PVL)的影响,并探讨其机制。方法选取3日龄新生鼠,随机分为PVL模型组、rEPO干预组及假手术组各24只。PVL模型组、rEPO干预组通过分离并结扎新生鼠左颈总动脉,随后给予低氧混合气体缺氧70 min进行PVL建模;假手术组只分离左颈总动脉,但不行结扎和缺氧处理。rEPO干预组在术后1 d开始连续腹腔注射rEPO 7 d,PVL组及假手术组腹腔注射相同容积生理盐水;三组分别于术后3、7、14 d随机选取8只处死并取脑组织,采用HE染色观察侧脑室及脑室周围白质组织形态、卢卡斯固蓝染色观察髓鞘组织形态,采用免疫组织化学法检测脑室周围白质区少突胶质细胞和髓鞘标志物2',3'-环核苷酸3'-磷酸二酯酶(CNPase)、少突胶质细胞前体标志物神经胶质抗原2(NG2)。结果PVL模型组及rEPO干预组可见左侧侧脑室较对侧扩大,脑室周围白质组织细胞水肿并伴囊腔、胶质瘢痕形成,髓鞘水肿、断裂,神经纤维走行紊乱等;术后同时点rEPO干预组病理改变均较模型组减轻,假手术组各时点无明显病理改变。术后同时点比较,三组新生鼠脑室周围白质组织CNPase表达假手术组>rEPO干预组>PVL模型组;NG2表达rEPO干预组>PVL模型组>假手术组(P均<0.05)。结论rEPO可通过增加少突胶质细胞及少突胶质细胞前体促进少突胶质细胞成熟及髓鞘形成,从而减轻脑缺氧、缺血引发的新生鼠PVL。

ObjectiveTo explore the effect and mechanism of recombinant human erythropoietin(rEPO)on the periventricular leukomalacia(PVL)of neonatal rats.MethodsRats of 3 days old were randomized into three groups:PVL model group,rEPO intervention group,and sham operation group,with 24 rats in each.In the PVL model group and the rEPO intervention group,PVL model were established by separating and ligating the left common carotid artery of neonatal rats,and then inhaling the hypoxic mixture for 70 minutes;in the sham operation group,only the left common carotid artery was isolated,but no ligation and hypoxia treatment were performed.The rats in the rEPO intervention group were given continuous intraperitoneal injection of rEPO for 7 days from the 1st day after operation,and the rats in the PVL group and the sham operation group were injected with the same volume of normal saline.On day 3,7,and 14 after the operation,8 animals were randomly sacrificed and their brain tissues were taken.HE staining was used to observe the morphology of the lateral ventricle and periventricular white matter tissues in each group,Lucas solid blue staining(LFB)was used to observe the myelin tissue morphology of each group,and immunohistochemistry was used to detect oligodendrocytes and myelin markers 2’,3’-cyclic nucleotide 3’-phosphodiesterase(CNPase),oligodendrocyte precursor marker glial antigen 2(NG2)in the white matter area.ResultsThe PVL model group and the rEPO intervention group showed that the left lateral ventricle was enlarged compared with the contralateral side,and there were periventricular white matter tissue cell edema accompanied with cystic and glial scar formation,myelin edema,rupture,nerve fiber movement disorder,etc.;the pathological changes in the rEPO intervention group at the same point after surgery were all lighter than those in the model group,and there were no obvious pathological changes in the sham operation group at all time points.Simultaneous comparison after operation showed that the CNPase expression was in the following order:sham operation group>rEPO intervention group>PVL model group,and the NG2 expression:rEPO intervention group>PVL model group>sham operation group(all P<0.05).ConclusionThe rEPO can promote oligodendrocyte maturation and myelination by increasing oligodendrocytes and oligodendrocyte precursors,thereby reducing PVL in newborn rats caused by cerebral hypoxia and ischemia.