Leptin from macrophages promotes Th17 differentiation and participates in inflammatory myocardial injury
Objective:To explore the role of Leptin and Th17 in the process of myocarditis injury.Methods:CVB3 was used to construct a viral myocarditis(VMC)model.First,the mice were divided into control group and VMC group.HE staining was used to detect myocardial inflammatory infiltration.The expression of Th17 in spleen tissue was measured by FACS.qRT-PCR was used to detect the expression of IL-17A mRNA in cardiac tissue.The level of IL-17A in serum was detected by ELISA.Secondly,Naïve CD4+T cells in the spleen tissues of normal and db/db(Leptin receptor deficiency)mice were isolated and divided into control group,Th17 group and Leptin+Th17 group,and the proportion of Th17 cells and the content of IL-17A in the culture supernatant were detected after differentiation culture.Finally,a VMC model was established after the removal of macrophages(Mφ)by clodronate liposome.The mice was divided into control group,VMC group and VMC+Liposome group.FACS was used to detect the proportion of Mφ(CD11b+F4/80+)in spleen and abdominal cavity and the proportion of Th17 in spleen.HE staining was used to detect myocardial inflammatory infiltration again.Leptin mRNA expression in cardiac tissue was detected by qRT-PCR.The level of Leptin and IL-17A in serum was detected by ELISA.Results:Compared with control group,myocardial inflammatory infiltration was increased in VMC group,the proportion of Th17 in spleen was up-regulated,and the expression of IL-17A mRNA in cardiac tissue and serum IL-17A were significantly increased(P<0.05).After isolation of CD4+T cells from normal mice in vitro,compared with Th17 group,the proportion of Th17 cells and the level of IL-17A in the culture supernatant were significantly increased in Leptin+Th17 group(P<0.05),while there was no significant difference in the proportion of Th17 and IL-17A content in the Lepr-/-CD4+T cells.In addition,after Mφ was knocked out in vivo,compared with the VMC group,the proportion of Mφ(CD11b+F4/80+)in spleen and abdominal cavity of mice in the VMC+Liposome group was significantly reduced,HE staining showed that myocardial inflammatory infiltration was relieved,Leptin mRNA expression in cardiac tissue,the proportion of Th17 in spleen and serum level of Leptin and IL-17A were significantly decreased.Conclusion:Mφ-derived Leptin is involved in myocarditis injury by regulating Th17 differentiation.
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维普
