巨细胞病毒感染后新生小鼠脑内Wif-1、Shh的表达变化

目的:探讨鼠巨细胞病毒(murine cytomegalovirus,MCMV)感染后新生小鼠脑内Wnt inhibitory factor-1(Wif-1)、Sonic hedgehog(Shh)信号分子的表达变化及对中枢神经系统发育的可能影响。方法:体外3T3细胞培养、MCMV接种增殖;60只生后3 d的BALB/c仔鼠随机分为正常对照组及病毒感染组,病毒组通过腹腔注射法建立新生小鼠中枢神经系统MCMV感染模型,而对照组则注射等量的生理盐水;每组设立3个时间点亚组(造模后3 d,7 d,14 d),相应时点处死仔鼠,取脑组织备用。通过RT-PCR检测两组各时点脑组织中的MCMV-DNA表达;Western Blot检测小鼠脑组织中Wif-1、Shh蛋白的表达;流式细胞术检测两组的细胞周期比例改变。结果:病毒组小鼠脑组织中MCMV-DNA的表达随着时间推移持续增多,而对照组3个时间点均阴性表达;病毒组小鼠脑组织中Wif-1分子的表达相对于对照组增强,而Shh分子的表达相比于对照组则表现出明显的抑制;病毒组小鼠脑组织中处于分裂期的细胞百分比较对照组下降。结论:MCMV感染后的新生小鼠脑组织内Wif-1表达增强,而Shh信号分子则下调,其表达异常变化可能影响Wnt、Hedgehog信号通路,并影响中枢神经系统成熟过程。

Effects murine cytomegalovirus infection on expression of Wif-1 and Shh in newborn mouse brains

Objective:To explore changes of Wnt inhibitory factor-1 (Wif-1) and Sonic hedgehog (Shh) protein expression in newborn mice brains by murine cytomegalovirus (MCMV) infection,in order to investigate the pathogenesis of neurological defects.Method:Sixty newborn BALB/c mice were randomly divided into viral group and control group.Mice in viral group were inoculated intraperitoneally with tissue culture passaged MCMV Smith strain,while mice in control group were inoculated with the same dose of normal saline.Mice in both groups were killed at day 3,7 and 14 (n =10 for each interval) and brain tissue was obtained for analysis.RT-PCR was used for detecting MCMV-DNA in brain tissue from two groups,Western Blot for observing the expressing of Wif-1,Shh protein,and flow cytometry for evaluating cell cycle.Result:In contrast to increasing expression of MCMV-DNA in viral group,none MCMV-DNA was detectable in brain tissue in control group.The expressing of Wif-1 protein in viral group was higher than that in control group.Nevertheless,the expressing of Shh protein,a crucial molecule in Hedgehog pathway,significantly decreased in viral group.Compared to control group,proportions of cells in the S phrase in brain tissue decline in the viral group.Conclusions:The expression of Wif-1 in newborn mice brains increased,while expression of Shh protein down-regulated in MCMV infection.These may result into the disturbance of Wnt and Hedgehog pathway,which then contribute to disturbamce of central nervous system development.