Research On Expression Of Synapsin I In The Hippocampus Of Rats Infected Congenitally By Human Cytomegalovirus

Objective To explore changes of the expression of synapsin I in the hippocampus of rats infected congenitally by human cytomegalovirus and influence of HCMV infection on murine learning and memory.The study aimed at providing a scientific experimental way to research on mechanism of learning disability caused by HCMV congenital infection. Methods Proliferatived with HEFL cells, cytopathic effect was +++～++++ (up to 75%), 5×10~4/ml cell suspension of HCMV AD169 strain was inoculated 5th generation HELF cells. HCMV (100TCID50 in 1ml/mice) were separately given to 8/9-week-old SPF SD 40 rats on 5 gestation days in experimental group with intra-abdominal injections. The equal quantity supernate of HELF cell were inoculated in mice of control group at the same times.And female: male = 3:1, the pregnant rats were randomly divided into experimental and control group, n = 15/ group. Offspring animal had grown to 30-40 days, and hippocampus of rats were put after recording.using HE staining with congenital HCMV infection of rat neuronal morphological changes in the hippocampus; Immunohistochemistry was used to observe the distribution of synapsin I in the hippocampus of rats infected congenitally by human cytomegalovirus; Also using Western Blot tested expression levels of synapsinⅠin the hippocampus, applicate SPSS 11.5 statistical software, and use t test for comparison. Results①Characteristic CPE was observed on the second day of inoculation and this cytopathic change aggravated as inoculation time prolonged;②The number of hippocampal cells significantly reduced,vacuolar degeneration and cells arranged in disorder can be seen in the HE staining under the electron microscope at 20 times;③Expression of SynapsinⅠin the hippocampus of rats infected congenitally by human cytomegalovirus were detected using immunohistochemistry,they are buffy particles in light microscope, and became less with the extension of time after infection. Average optical density (AOD) of synapsin I positive products was measured by image analysis. AOD of infection group was 0.172±0.070, and control group was 0.295±0.047. using t test to compare, P <0.01 indicated a significant difference between the two groups;④Western blot gray value of synapsin I in the hippocampus of the infected groups and control groups was determined by Quantity One analysis software. The application SPSS 11.5 statistical software and using t test compare with the two groups. Synapsin I of congenital infection groups in hippocampus of rats was significantly lower than the control groups (P <0.01), and the result of Immunohistochemistry is consistent with Western Blot. Conclusion Expression of synapsin I significantly decreased in the hippocampus of offspring rats of HCMV infection in first Trimester, suggesting that learning and memory and expression of synapsinⅠin hippocampus were significantly related with congenital HCMV infection.