摘要目的 探讨早产儿脑白质损伤(WMD)的发病机制及氙气的神经保护作用机制.方法 将3日龄SD新生大鼠96只按照出生时间编号后采用随机数字表法随机分为空白对照组(24只)、WMD对照组(24只)、氙气干预A组(24只)和氙气干预B组(24只).WMD对照组及氙气干预2组予腹腔注射脂多糖(LPS)0.05 mg/kg,并结扎右侧颈总动脉联合缺氧1h处理,建立WMD新生大鼠模型;空白对照组仅腹腔注射9g/L盐水(0.05 mg/kg),不给予颈动脉结扎和缺氧处理.氙气干预A组和B组分别在模型建立后0、2h予500 mI/L氙气吸入处理3h.各组分别于干预处理后0、24、48、72 h采用随机数字表法随机各选取6只大鼠进行断头取脑,给予HE染色,髓鞘碱性蛋白(MBP)免疫荧光染色,实时定量聚合酶链反应检测脑组织中CLIC4 mRNA的表达水平.结果 1.脑组织病理:与空白对照组比较,WMD对照组右侧脑白质结构疏松、紊乱,可见核固缩、胞质疏松等改变;氙气干预2组也均可见上述表现,但较WMD对照组明显减轻,A、B2组间无明显差异.2.MBP测定:WMD对照组右侧脑白质MBP阳性细胞数量较空白对照组明显减少,但氙气干预2组MBP阳性细胞数量较WMD对照组明显增加.3.CLIC4 mRNA表达水平:除了氙气干预A组的24h外,WMD对照组及氙气干预A组和B组右侧脑白质CLIC4 mRNA的表达水平在其余时间点均高于空白对照组,差异均有统计学意义(均P＜0.05);但与WMD对照组相比,氙气干预A组与B组在各时间点CLIC4 mRNA的表达水平均明显降低,差异均有统计学意义(均P＜0.05);氙气干预A组与B组脑组织中CLIC4 mRNA表达水平差异无统计学意义(P＞0.05).结论 WMD新生大鼠脑白质CLIC4 mRNA表达水平明显升高,表明线粒体途径是WMD的病理过程之一;氙气早期干预可通过降低CLIC4mRNA的表达,减轻WMD,从而发挥神经保护作用.

abstractsObjective To investigate the mechanism of white matter damage (WMD) and the neuroprotective effect of Xenon on neonates with WMD.Methods Three-day-old SD rat pups (n =96) were randomly divided into the blank control group (n =24),the WMD control group (n =24),the Xenon intervention group A (n =24) and the Xenon intervention group B (n =24) by random number method according to their birth time.WMD rat models were successfully established by giving intraperitoneal injection of lipopolysaccharide(LPS) 0.05 mg/kg combined with carotid artery ligation and hypoxia for 1 hour in the WMD control group and the Xenon intervention groups.In the control group,only 9 g/L saline (0.05 mg/kg) was injected intraperitoneally,while carotid artery ligation and hypoxia were not administered.Rats in Xenon intervention group A and group B were given inhalation of 500 mL/L Xenon for 3 hours at 0 and 2 hours respectively after establishment of the models.Six rats in each group were randomly selected and decapitated at 0,24,48 and 72 hours after the intervention.The brain white matter on the right was analyzed by using HE staining and myelin basic protein(MBP) immunofluorescence staining,and real-time quantitative polymerase chain reaction was used to detect the expressions level of CLIC4 mRNA.Results (1) Brain tissue pathology:compared with the blank control group,the brain white matter on the right of the WMD control group and the Xenon intervention group A and group B had loose and disordered structure,nuclear pyknosis and cytoplasm loosening.However,the lesions in both Xenon intervention group A and group B were significantly less than those in the WMD control group,and there was no significant difference between the Xenon intervention group A and group B.(2) MBP measurement:the number of MBP-positive cells in the brain white matter on the right of WMD control group was significantly lower than that in the blank control group,while compared with WMD control group,they were significantly higher in Xenon intervention group A and group B.(3) CLIC4 mRNA expression level:compared with blank control group,the expressions levels of CLIC4 mRNA at most time point were higher both in the WMD control group and the Xenon intervention group A and group B (all P ＜ 0.05),except the time point 24 h in the Xenon intervention group A.The expressions of CLIC4 mRNA in group A and group B were significantly decreased compared with those in the WMD control group (all P ＜ 0.05).However,there were no significant differences between Xenon intervention group A and group B (P ＞ 0.05).Conclusions The expressions of CLIC4 mRNA in brain tissues on neonatal rats with WMD significantly increased,indicating that the mitochondrial pathway could be one of the pathological processes of WMD.Early Xenon intervention may reduce neonatal WMD by reducing the expression of CLIC4 mRNA,which plays a neuroprotective role.