摘要目的 观察新生小鼠颅内感染鼠巨细胞病毒(murine cytomegalovirus,MCMV)后听性脑干反应(ABR)反应阈值的变化以及蜗神经核细胞内游离钙([Ca2+]i)和钙调素(calmodulin,CaM)的变化.方法 69只新生小鼠(出生24 h内)随机数字表法分为实验组和对照组,实验组(54只)经颅内注射MCMV悬液20μl,对照组(15只)颅内注射无菌生理盐水20μl.1个月后小鼠在麻醉状态下行ABR检测,并记录反应阈.测完反应阈后,麻醉处死小鼠,分离蜗神经核,流式细胞仪测定蜗神经核细胞内[Ca2+]i的荧光强度,反转录聚合酶链反应(RT-PCR)测定CaM mRNA的表达.比较实验组与对照组各检测指标的差异.结果 实验组小鼠ABR阈值[(84.5±2.7)dBSPL]高于对照组[(64.0±1.3)dBSPL],差异具有统计学意义(F=2.789,P =0.000).实验组小鼠蜗神经核[Ca2+]i浓度较对照组增高(F=1.290,P =0.000),CaM mRNA表达较对照组增多(F=4.252,P =0.023),差异均具有统计学意义.结论 颅内感染MCMV可以引起小鼠ABR阈值升高,蜗神经核细胞内[Ca2+]i及CaM mRNA表达的增高可能是MCMV感染导致感音神经性聋的机制之一.

abstractsObjective To investigate the changes in the threshold of auditory brainstem response (ABR),[Ca2+]i and calmodulin(CaM)in cochlear nucleus of the newborn mice infected by murine cytomegalovirus(MCMV)in the brain.Methods Sixty-nine newborn mice were randomized into the model group and the control group.The model group(54 mice)was established by intracranial injection with MCMV viral suspension 20 μl,and the same volume of 0.9％ sodium chloride was injected in the control group(15 mice).After one month,the ABR was tested in a sound-electric screen environment and the threshold was recorded.Then intracellular free calcium [Ca2 +] i and the mRNA level of CaM in the cochlear nucleus were assayed by flow cytometry and RT-PCR.Results Compared to the control group [(64.0 ±1.3)dBSPL],the threshold of ABR in the model group [(84.5 ±2.7)dBSPL] was increased(F =2.789,P =0.000).Moreover,in the model group the intracellular free calcium [Ca2 +] i and the mRNA level of CaM in the cochlear nucleus were increased(F =1.290,P =0.000;F =4.252,P =0.023),the differences were statistically significant.Conclusions The intracranial injection of MCMV can lead to abnormal changes in the threshold of ABR in mice,and the change of [Ca2 +]i/CaM in cochlear nucleus may be the important pathological basis of sensorineural hearing loss induced by MCMV infection.