Altreation Of B10 Cells In Mice With Acute Viral Myocarditis

Objective:Observating the changes of splenic B10 cells in the Coxsackie virus B3 (CVB3)-induced acute viral myocarditis (AVMC) in mice at different time points, and to explore the role of B10 cells in the pathogenesis of AVMC.Methods:Specific pathogen-free male Balb/c mice were intraperitoneally (i. p.) infected with CVB3 to establish AVMC models. CVB3 was diluted in PBS, Balb/c mice infected by an i. p. injection of 0.1 mL of PBS containing approximately 100 TCID50 of the CVB3 were taken as AVMC group (n=20) and according to the time point post injection, the AVMC group and control group mice were randomly separated into 2 subgroups:1 week subgroup and 2 week subgroup. The day when mice were injected i. p. was defined as 0 week, all surviving animals were sacrificed at 1 week and 2 weeks after i. p. injection, and spleens as well as myocardial tissues were aseptically collected. Myocardial histopathological changes were observed by hematoxylin and eosin staining and myocardial histopathological scores were calculated. Expression of CVB3 mRNA in heart was measured by real time-polymerase chain reaction (RT-PCR). The frequency of splenic CD19+IL-10+subsets (B10 cells) and CD19+CD1dhiCD5+ subsets in CD19+ B cells was measured by flow cytometry.Results:There were significant difference on the pathological scores and the expression of myocardial CVB3 mRNA between the AVMC mice and the control ones, and the pathological scores of 1 week AVMC subgroup were lower than those of 2 week AVMC subgroup, but the expression of myocardial CVB3 mRNA in 1 week AVMC subgroup was higher than that in 2 week AVMC subgroup (all p<0.05). Compared with controls, the frequency of splenic B10 subsets and CD19+CDldhiCD5+ subsets in the AVMC mice increaesed significantly at different time points. More over, the the frequency of splenic B10 subsets and CD19+CDldhiCD5+ subsets in 1 week AVMC group was higher than that in the 2 week AVMC group (allp<0.05).Conclusion:Our data showed that the frequency of B10 cells increased in CVB3-induced AVMC, indicating that B10 cells may participate in the pathogenesis of CVB3-induced AVMC.