To study the effects of mouse cytomegalovirus （MCMV） on the in vitro maturation, fertilization, cleavage and blastula formation of mouse oocytes, the immature oocytes were infected in vitro by MCMVs of different dosages （100 TCID50, 10 TCID50 and 1 TCID50）. The oocytes were then observed for in vitro maturation, fertilization, cleavage and blastula formation and the ultrastructural changes after the culture with the viruses. Our results showed that no significant differences were found in IVM, IVF, cleavage and blastula formation among the groups treated with of virus of various dosages. And ultrastructural abnormality was observed in the oocytes treated by 100 TCID50 of viruses. It is concluded that MCMV did not have any conspicuous effects on IVM, IVF, cleavage and blastula formation of murine immature oocytes.
This study examined the impacts of intrauterine murine cytomegalovirus（MCMV） infection on the long-term learning and memory of offspring.Sexually matured male and female BALB/C mice without MCMV infection were identified by ELISA and then mated.Seventy pregnant mice were randomly divided into the virus group（n=40） and the control group（n=30）,in which the pregnant mice were subjected to placenta inoculation of MCMV suspension（1 μL,1×106 PFU） or the same amount of cell culture medium,respectively,at gestational age of 12.5 days.Some pregnant mice [virus group（n=20）,control group（n=15）] were sacrificed by cervical dislocation at gestational age of 18.5 days,and the head circumference and brain weight of the mouse fetuses were measured,and the MCMV infection in their brain tissues was detected by PCR.The other pregnant mice [virus group（n=20）,control group（n=15）] delivered naturally,and the learning and memory capability of the offspring at 70-day-old was analyzed by Morris water maze test.The results showed that 28.57% mouse fetuses in the virus group developed viral infection in the brain.Their head circumference and brain weight were significantly reduced as compared with those in the control group（P0.01）.The Morris water maze test revealed that the mouse offspring in the control group found the platform with straight-line trajectories after training.In contrast,the counterparts in the virus group intended to enter the central area,but looked for the platform with a circular trajectory.And the infected mice exhibited prolonged swimming distance and swimming latency（P0.01）.It was concluded that：（1） placenta inoculation of MCMV can cause fetal brain infection and intrauterine development retardation;（2） the offspring of MCMV placenta inoculation mice showed a long-term decline in learning and memory capability.
