ABSTRACT
Objective 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.