先天性人巨细胞病毒感染胎鼠大脑皮质钙调素基因mRNA的研究

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Changes of calmodulin mRNA in the cerebral cortex of fetal mice infected congenitally by human cytomegalovirus

Objective To obtain the evidence of the changes of calmodulin gene expression in the brain of congenital infection by human cytomegalovirus (HCMV). Methods 32 Balb/c mice aged 10 weeks were chosen. The model of congenital central nervous system infection was established by injecting abdominally 1.00 ml, 0.50 ml , 0.25 ml HCMV into female and male mice respectively, then the mice were matched in a cage. The controls were injected abdominally with 1.00 ml RPMI 1640 Medium. The cerebral cortexes, which were collected the 21 days fetal mice removed from the uteri, were studied using reverse transcriptase polymerase chain reaction (RT PCR) and in situ hybridization histochemistry. The relative concentrations of RT PCR products were calculated by their value of OD 260 detected with type UV 754 spectroradiometer, and the gel electrophoresis was done for them. Results The concentrations of RT PCR products derived from 1.00 ml and 0.50 ml groups were markedly higher than those in 0.25 ml group and control group, however there was obvious difference in between 1.00 ml and 0.50 ml group. The electrophoresis showed that there were not any positive bands in 0.25 ml group and the controls, whereas the signal of specific positive bands in 1.00 ml group was stronger than that in 0.50 ml group and slightly weaker than that in the mother group. In situ hybridization demonstrated that the higher density of calmodulin mRNA positive signals existed not only in the cytoplasm and nucleus of large neurons but also in the cytoplasm and nucleus of moderate or small neurons and gliocytes of cerebral cortex in 1.00 ml fetal mice, and that the cell processes were weakly stained. There were no obviousy positive signals in 0.50 ml, 0.25 ml group, and control group and in 1.00 ml negative control group without probes, respectively. Conclusion Congenital HCMV infection resulted in marked mRNA increase of calmodulin gene in cerebral cortex of fetal mice, which showed the positive association between various titers and gene expression, and the over expression of calmodulin mRNA existed in not neurons and also in gliocytes.