中文摘要：

目的观察新生小鼠颅内感染鼠巨细胞病毒（murinecytomegalovirus，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24h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20Ixl。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CaMmRNA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），CaMmRNA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CaMmRNA表达的增高可能是MCMV感染导致感音神经性聋的机制之一。

英文摘要：

Objective 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.