延迟亚低温对新生幼鼠脑白质损伤的改善作用

Ameliorative Effect of Delayed Mild Hypothermia on White Matter Injury in Neonatal Rats

目的探讨延迟亚低温对氧糖剥夺-复氧复糖诱导新生幼鼠脑白质损伤的改善作用及其可能机制。方法建立40只新生幼鼠全脑灌流和氧糖剥夺模型,随机平均分为4组进行延迟亚低温干预,每组各10只。用免疫荧光法分析各组脑切片髓鞘碱性蛋白(myelin basic protein,MBP)表达、少突胶质前体细胞(oligodendrocyte precursor cell,O4)数量。采用实时荧光定量聚合酶链反应(real-time quantitative polymerase chain reaction,RT-qPCR)检测M1型和M2型小胶质细胞相关基因表达。结果在亚低温32℃延迟24、48和72h组MBP蛋白荧光强度均高于对照组,且荧光强度随着延迟时长的增加而递增;O4细胞数量均高于对照组(F分别为314.907,P<0.001),且发现细胞数量的增加与延迟时长呈显著正相关(r=0.968,P<0.001);M1型小胶质细胞的CD32、iNOS表达均低于对照组(F分别为41.451、92.912,P均<0.001),且CD32、iNOS表达均与延迟时长呈显著负相关(r分别为-0.868、-0.916,P均<0.001);M2型小胶质细胞的CD206、IL-10表达均高于对照组(F分别为79.699、63.839,P均<0.001),且CD206、IL-10表达均与延迟时长呈显著负相关(r分别为0.862、0.910,P均<0.001)。结论延迟亚低温能有效改善氧糖剥夺-复氧复糖诱导新生幼鼠脑白质损伤,其机制可能与增加O4数量和促进小胶质细胞向M2型极化有关。

Objective To investigate the ameliorative effect of delayed mild hypothermia on white matter injury induced by oxygen-glucose deprivation and restoration in neonatal rats and its possible mechanism.Methods Forty neonatal rats were randomly divided into four groups for delayed mild hypothermia,10 rats in each group.The expression of myelin basic protein(MBP)and the number of oligodendrocyte progenitor cells(O4)in brain sections of each group were analyzed by immunofluorescence.The gene expression in M1 and M2 microglia was detected by real-time quantitative polymerase chain reaction(RT-qPCR).Results The fluorescence intensity of MBP protein in the mild low temperature 32℃delay for 24h,48h and 72h groups were higher than those in the control group,and the fluorescence intensity increased with the increase of the delay time.The number of O4 cells was higher than that of control group(F=314.907,P<0.001),and the increase of cell number was significantly positively correlated with delay time(r=0.968,P<0.001).The expression of CD32 and iNOS in M1 microglia was lower than that in control group(F were 41.451,92.912,all P<0.001).The expression of CD32 and iNOS was negatively correlated with the delay time(F were-0.868,-0.916,all P<0.001).The expression of CD206 and IL-10 in M2 microglia was higher than that in control group(F were 79.699,63.839,all P<0.001).The expressions of CD206 and IL-10 were significantly negatively correlated with the delay time(F were 0.862,0.910,all P<0.001).Conclusion Delayed mild hypothermia can effectively ameliorate the damage of white matter injury induced by oxygen-glucose deprivation and restoration in neonatal rats,its mechanism may be related to increase O4 quantity and promote microglia M1 to M2 polarization.