Interleukin 17 level changes in different stages of Coxsackie virus-induced myocarditis in mice

Abstract

Objective To investigate IL-17 and IL-23 levels change in Coxsackie virus-induced myocarditis in mice,aiming at effect of IL-17 in viral myocarditis.Methods A total of 100 male BALB/c mice,4 weeks old,including 80 in the viral myocarditis (VMC)group and 20 in the control group,were used.Mice in VMC group were peritoneally injected (PI)with Coxsackie virus B3(CVB3/Nancy).Mice were sacrificed at day 14,28,42 and 56 after PI.For different stages post infection,pathological changes of the mouse were observed,and IL-17 of heart by immunohistochemistry.Splenocytes were collected from the mice and restimulated with phytohemagglutinin (PHA)for 2 days in vitro.IL-17 mRNA and IL-23 mRNA of splenocytes were measured by RT-PCR and compared with those in the control.Results (1)IL-17 mRNA extracted from splenocytes increased at day 28 after PI as compared with that in the control and 14 days (both P＜0.01),and decreased at day 42 and 56.(2)All of the VMC group and control mice expressed IL-23 mRNA,but IL-23 mRNA level,which up-regulated at day 14,increased earlier than IL-17 mRNA,and continued to rise to a high level after that.(3)Heart IL-17 level which examined by integrate optical density also increased at day 28 of viral myocarditis in mouse as compared with that in the control and 14 days ( both P＜0.01).And the protein levels decreased at day 42 and 56 then.Conclusion The mRNA and protein levels of IL-17 were promoted in Coxsackie virus-induced myocarditis mice after 28 days.IL-23 mRNA expression was up-regulated also.This result suggested that Th17 subset is differentiated in chronic stage of viral myocarditis. Key words: Interleukin; Coxsackie virus; Myocarditis; Mice