HMGB1炎性通路在巨细胞病毒感染性听力减退中的作用

Role of HMGB1 inflammatory pathway in CMV-induced hearing-loss

目的:明确HMGB-1相关炎性通路与巨细胞病毒(CMV)先天性感染导致听力减退之间的关系。方法:采用小鼠CMV颅内接种法感染新生小鼠,以注射生理盐水的乳鼠为对照,比较两组小鼠生长发育情况;测定两组2周龄小鼠的听性脑干反应(ABR)阈值;采用RT-PCR检测耳蜗组织HMGB-1 mRNA表达,Western Blot检测RAGE和IκBα蛋白表达。结果:感染组小鼠死亡率63.6%,生长发育异常,ABR阈值明显高于对照组[(28.42±3.03)dB vs(15.66±0.38)dB,P<0.01]。感染组耳蜗组织检出CMV mRNA,且HMGB-1 mRNA表达明显高于对照组(3.124±1.836 vs 1.077±0.085,P<0.05)。与对照组比较,感染组RAGE蛋白表达显著增加而IκBα表达显著降低(均P<0.01)。结论:HMGB-1/RAGE/NF-κB炎性通路可能在CMV先天性感染所致听力减退的发病机制中占据重要地位,或可为未来治疗提供潜在靶点。

Objective:To probe into the role of HMGB-1-related inflammatory pathway in the pathogenesis of CMV-induced hearing loss.Methods:MCMV-free BALB/c mice were screened by ELISA assay of MCMV-specific IgM/IgG antibodies.After overnight mating,pregnant mice were separately bred.The newborn pups were randomly divided into two groups:MCMV-infected group(infected group),which was intracerebrally inoculated with viral suspension in the first 24 hours after birth,and control group,which was injected with sterile 0.9%sodium chloride of equal volume.We recorded the living and developing condition of the pups,measured the ABR thresholds of the mice two weeks later.MCMV and HMGB-1 mRNA in the cochleae were assayed by RT-PCR,in the meantime the expression of RAGE and IκBαwere measured by Western Blot.Results:Of the 121 pups of the in-fected group,44 survived with notable anomaly two weeks after birth,while all the pups of the con-trol group normally developed.The ABR thresholds of the two groups were(28.42±3.03)dB(in-fected)and(15.66±0.38)dB(control),respectively(P<0.01).In the cochlear extract,MCMV mRNA was detected in the infected group,and the relative abundance of HMGB-1 mRNA were 3.124±1.836 in infected group versus 1.077±0.085 in control group,with significant difference(P<0.05).According to the results of Western Blot,the RAGE level was conspicuously higher while the IκBαapparently lower in infected group(P<0.01).Conclusion:The HMGB-1/RAGE/NF-κB pathway might play an important role in the pathogenesis of hearing loss induced by congenital CMV infection.