柯萨奇B_3病毒经晚期孕鼠胎盘致母婴感染的小鼠动物模型研究

Study on experimental model of transplacental infection of coxsackievirus B_3 from the mother to the fetus in late gestation mice

目的 :探讨柯萨奇B3病毒(CVB3m)在母婴间经胎盘垂直传播的可能性和条件 ,并建立小鼠动物模型。方法 :对不同孕期的母鼠分别接种最佳感染量柯萨奇B3病毒嗜心肌株 (CVB3m) ,剖腹取胎或产仔。对母鼠、胎鼠、仔鼠及胎盘分别进行病毒学、血清学及病理检查。结果 :晚期孕鼠接种适量的CVB3m后次日形成病毒血症 ,此时血中无抗CVB3m中和抗体。病毒经胎盘传播形成母婴垂直感染。胎盘、胎鼠、母鼠心肌及仔鼠血清和心肌中均查到较高滴度的病毒。电镜下可见受染仔鼠心肌细胞线粒体肿胀、嵴突缺失、肌纤维断裂、明暗带模糊等初期病变。结论 :晚期孕鼠感染CVB3m后形成病毒血症 ,通过胎盘屏障将病毒传至胎儿 ,引起胎鼠及仔鼠心肌病变 ,可作为防治CVB3

AIM: To study the possibility and conditions of transplacental infection of coxsackievirus B3(CVB 3) from pregnant mice to their fetuses and newborns. METHODS: Coxsackievirus B 3 strain causing balb/c mice myocardial injury(CVB 3m )was inoculated with 10 5 TCID 50 in dose into the mother mice at 6-7 days (early gestation),9-10 days (middle gestation) and 17-18 days (late gestation) of gestation, in contrast with non pregnant mice. Some placentas and fetuses were removed by caesarean section before mothers partusing; some mothers and their babies were sacrificed after parturition, and virus isolation, serological and pathological tests were performed. RESULTS: Viramiae was observed in mother mice of late gestation inoculated with CVB 3m at a fit amount on the second day after inoculation, while no newtralizing antibody to CVB 3m was detected in blood. The virus was isolated from cardiac muscles of inoculated mother mice in different gestation and the controls. The virus was also isolated from some placentas and fetuses, and both sera and cardiac muscles of infants in the late gestation (virus titer were all 10 -2 -10 -3 ). On d 7 of inoculating virus, pregnant and non pregnant mice titers of neutralizing antibody to CVB 3m in sera were all between 1160 and 1320. Under the electromicroscopy, some cardiac muscle cells of mother or infant mice appeared with morphological changes and little hollow bubbles occured in cytoplasm. The fibers broke off, and the bright and dark belts became indistinct. CONCLUSION: The amimal model, intraplacental passage of CVB 3 from pregnant mother in late gestation to fetus in mice, is a benefitial tool to study enterovirus diseases in human perinatal period.