早期干预对宫内感染致脑损伤仔鼠大脑少突胶质细胞髓鞘糖蛋白mRNA表达的影响

Effect of Early Intervention on Oligodendrocyte-Myelin Glycoprotein mRNA Expression of Neonatal Rats with Brain Injury Caused by Intrauterine Infection

目的观察早期干预对宫内感染致脑损伤仔鼠大脑少突胶质细胞髓鞘糖蛋白(OMgp)mRNA表达的影响。方法 1.将28只孕鼠随机分为对照组和脂多糖(LPS)组,受孕18d时LPS组予孕鼠LPS450μg·kg-1连续2d腹腔注射,对照组孕鼠腹腔注射同等剂量的9g·L-1盐水。仔鼠出生后取母鼠胎盘行HE染色观察宫内感染情况。2.随机选取对照组仔鼠30只,LPS组仔鼠55只(其中干预组、非干预组各25只),1日龄时选取对照组和LPS组仔鼠各5只做病理检测,观察脑损伤情况。3.出生2d起,干预组仔鼠给予早期触摸及早期丰富环境刺激,对照组和非干预组常规饲养。4.取1日龄、3日龄、7日龄、4周龄、6周龄每组各5只仔鼠,应用反转录-PCR方法检测其脑组织OMgP mRNA相对水平。结果 1.对照组胎盘病理检测未见炎性反应;LPS组胎盘病理检测见胎盘内血管充血、水肿,并见大量中性粒细胞浸润。2.脑组织病理学检测示1日龄仔鼠对照组白质结构完整,布局有序,核淡,核仁清楚;LPS组脑白质、胼胝体、内囊部位可见组织疏松,胶质细胞聚集,囊间少突胶质细胞减少,并可见脑室内出血、脑白质内血管扩张、脑白质内毛细血管破裂出血。3.LPS组1日龄、3日龄、7日龄、4周龄、6周龄仔鼠脑组织OMgp mRNA的表达均较对照组升高(Pa<0.05);干预组7日龄、4周龄、6周龄仔鼠脑组织OMgp mRNA的表达均较非干预组下降(Pa<0.05)。结论 1.宫内感染致脑损伤后,OMgp mRNA的表达均明显上调,形成不利于中枢神经系统再生的微环境,阻碍神经损伤的修复和功能重组;2.早期干预可使OMgp mRNA的表达量下降,促进中枢神经系统再生及神经损伤的修复和功能重组。

Objective To observe the effect of early intervention on the oligodendrocyte-myelin glycoprotein（OMgp） mRNA expression of brain injury neonatal rats caused by intrauterine infection.Methods 1.Twenty-eight Wistar pregnant rats were randomly divided into 2 groups：lipopolysaccharide（LPS）-treated group and saline control group.Pregnant rats were consecutively injected with LPS （450 μg·kg-1） or saline on the 18th gestation age.After birth,the placentas were taken out and made HE staining to observe intrauterine infection.2.Thirty neonatal rats in the saline control group and 55 rats in the LPS-treated group were randomly selected which were divided into intervention group （n=25） and no-intervention group （n=25）.The second post-natal day （P2） rats in intervention group were treated by early touch and enriched environment.The neonatal rats in the no-intervention group and saline control group were fed in a routine way.Five cases of P1 rats were selected respectively from the LPS-treated group and saline control group,and brain tissue pathological section was made to observe the condition of brain injury.3.Five cases of P1,P3,P7,P28 and P42 rats were selected from the saline control group,intervention group and no-intervention group to detect the OMgp mRNA expression levels by using the real time polymerase chain reaction me-thod.Results 1.There were a great number of neurophilic granulocytes in the placentas in the LPS-treated group.2.Brain tissue pathological of P1 in the saline control group had complete substantia alba structure,ordered disposition and lightly stained clear chromatospherite.While in the LPS-treated group, there existed brain tissue looseness,colloid cell aggregation and oligodendrocyte cytoreduction in the position of substantia alba,callositas and capsula interna.Intraventricular hemorrhage,substantia alba blood vessel dilatation and blood capillary angiorrhexis and hemorrhage could also be found.3.There was a higher increase in OMgp mRNA expressions of brain tissue in the LPS-treated group at P1,P3,P7,P28,P42 than those in the saline control group （Pa〈0.05）.The OMgp mRNA expressions of brain tissue of P7,P28,P42 neonatal rats in the intervention group was less than those in the no-intervention group （Pa〈0.05）.Conclusions 1.After the brain injury,the expression of OMgp mRNA is apparently increased,which forms a disadvantageous environment for the central nervous system regeneration and functional recombination.2.Early intervention can decrease the expression of OMgp mRNA and promote central nervous system regeneration and functional recombination.