An Experimental Study On Expression Of INOS In Cerebral Cortex Of Fetal Mouse Congenitally Infected With HCMV

objective The study aimed at investigating the expression of inducible nitric oxide synthase (iNOS) and pathological injury in cerebral cortex of fetal mice which were congenitally infected with human cytomegalovirus(HCMV) first and then intervened with different doses of iNOS inhibitor and accelerant. Methods The study has two parts. The first one was to investigating the effect of iNOS on the central nervous system(CNS) of fetal mice which were congenitally infected with HCMV. Thirty six 6~8 week BALB/c mice were divided into 6 groups, three femal and three male mice in each group. The mice in group A were subjected to the intraperitoneal injection of 100TCID50 HCMV 1. 0 ml per mouse. AG was injected into the intraperitoneum of mice in group B (200 mg/d/kg) and group C(20 mg/d/kg) respectively after two days of HCMV infection. The mice in group D and group E were subjected to the intraperitoneal injection of 300 mg/d/kg and 30 mg/d/kg L-.\rg respectively after two days of HCMV infection. Group F was a normal control gruop. On the 19th day in gestation and just before delivery, the brains of fetuses were collected by laparotomy. Body weight of each fetal mouse was measured .Human fetal fibroblasts (HF) grown as monolayers in cell culture were inoculated with brain homogenate for virus isolation. For pathology research,the cerebral cortexes of fetuses in each group were fixed , embedded. Sections, were cut then stained with hematoxylin-eosin(H. E. ), and examined with light microscopes.NOmetabolizable product was assayed by NO enzyme Kit. The expression of HCMV UL83 gene was detected by in suit nucleic acid hybridization assay. . The second part was to study on relationship between the expression of -iNOS and ultrastructures of cerebral cortex of fetuses in these groups. The grouping and treatment of mice were the same as those described in PART I .The brains of fetuses were collected for assays below: (1)iNOS mRNA was assayed by semi-quantitative RT-PCR. (2)iNOS was assyed by immunofluorescent test. (3)The numerical densities of synapse and mitochondrion in the cerebral cortex of HCMV congenitally infected fetal mice were observed by electron microscopes. Results HCMV can vertically transmit from the placenta of mice to infect their offspring in the central nervous system(CNS). Virus replication and pathological injury in fetal cerebral cortex were intervened by iNOS intervenors. The vertically transmition of HCMV was effectively interrupted by high dose iNOS accelerant. Lower virus replication .milder phathological injury and less NO metabolizable product were observed in the fetal cerebral cortex in this group compared with those of only HCMV infection group. The mean body weight of fetuses in high dose iNOS accelerant group was also significantly higher than that of HCMV infection group.By contrast, the vertiacally trasmition of HCMV was not interrupted by high dose iNOS inhibitor. Higher virus replication .severer phathological injury , lower mean body weight of fetuses and more NO metabolizable product were observed in this group compared with those of only HCMV infection group. The research on relationship between ultrastructures of fetal cerebral cortex and the expression of iNOS gene showed that higher relative expression of iNOS and lower numerical densities of synapse and mitochondrion in cerebral cortex of fetal mice in high dose iNOS inhibitor group,while the reverse result was observed in the high doseiNOS accelarant group. Our research showed that the relative expression of iNOS was negatively correlated with numerical densities of synapse and mitochondrion. Correlative coefficent and P value were - 0. 667(P<0. 005) ;-0.770(P<0. 001) respectively. Conclusion Lower virus replication and milder pathological injury in the cerebral cortex of fetal mice which were congenitally infected with HCMV were induced by high dose iNOS accelerant. The numerical densities of synapse and mitochondrion in the cerebral cortex of HCMV congenitally infected fetal mice had negative correlation with iNOS expressi...