[Histologic change in human cytomegalovirus-infected explants of first trimester human placenta and expression of human cytomegalovirus gene].

Objective: To observe histologic changes of human cytomegalovirus (hCMV)-infected explants of first trimester human placenta and expression of hCMV gene in the hCMV-infected explants, and investigate the mechanism of intrauterine transmission of hCMV from mother to fetus.

Methods: The first trimester placenta explants cultures were carried out, and they were infected with hCMV for 10 days. The expression of hCMV immediate early protein (IEP) 72-IEP86 were determined using indirect-immuno fluorescent assay, and in situ hybridization method was used to examine the hCMV late gene (LG) mRNA. For histologic evaluation of morphological changes in villi, transmission electron microscope was used.

Results: (1) Typical hCMV-induced lesions bearing hCMV IEP72-IEP86 were consistently localized in the trophoblast of covering placenta villi, interstitial cell and vascular endothelia cell 12 hours after infection, and were predominant in cytotrophoblast. (2) Replication of hCMV in placenta explants culture occurred from 12 hours to 24 hours and disappeared since 48 hours after infection with different concentrations of hCMV when examined by in situ hybridization. (3) Tissue integrity and viability of first trimester placenta explants were obtained in culture for 10 days and then explants were infected with different concentrations of hCMV [100 tissue culture infectious doses (TCID(50)), 200 TCID(50) and 300 TCID(50)], the progression of the infection was observed in the tissue that maintained its normal cellular organization under light microscope. But typical inflammation of cellular organization was observed under transmission electron microscope.

Conclusions: (1) A flash replication of hCMV in placental explants culture occurs; IEP72-IEP86 may be in intrauterine infection of hCMV for a long time. (2) There are pathological ultrastructure changes in hCMV-infected explants.