Expression of Th17 and Tc17 cells in the peripheral blood, skin and lung in a murine model of bleomycin-induced systemic sclerosis / 中华微生物学和免疫学杂志

ABSTRACT

Objective To study the expression and significance of Th17 and Tc17 cells in the peripheral blood,skin and lung in a murine model of bleomycin (BLM)-induced systemic sclerosis (SSc).Methods Thirty female BALB/c mouse were randomly divided into 3 groups,including a control group ( A group),a injected with BLM 4 week without pulmonary fibrosis(PF) group( B group) and with obviously PF group(C group).Pathological changes of skin and lung were detected.The proportion of CD4+,CD8+,CD4+IL-17+(Th17),CD8+IL-17+(Tc17) cells in the peripheral blood,skin and lung of mouse was determined by flow cytometry.The mRNA expressions of RORγt,IL-17A in skin and lung of mouse were evaluated by real-time PCR.Enzyme linked immunosorbent assay(ELISA) was used to measure the levels of IL-17 in serum.Results Dermal hydroxyproline(HYP) contents and the score of PF were significantly increased in C group [ (3.07±1.26) μg/mg,4.0±1.41 ]and B group [ (2.43±0.61) μμg/mg,1.50±0.76]as compared with A group [ (1.45±0.40) μg/mg,0.60±0.70 ],and pulmonary HYP contents was obviously increased in C group than in A and B groups,all P＜0.05.Compared with the A group,the percentage of CD4+ and Th17 cells in the peripheral blood,skin and lung of B and C groups,Tc17 cells of C group was significantly increased,and CD8+ cells was significantly decreased(all P＜0.05).The ratio of Th17/CD4+CD8+ in the peripheral blood,skin and lung of B and C groups [ ( 1.41 ±0.36)％,( 1.79±0.77)％ ],[ (2.58±1.07)％,(5.23±2.34)％ ]and [ (3.50±1.20)％,(4.02±1.32) ％ ]was significantly increased compared with A group (0.71±0.25)％,(1.15±0.59)％,(0.99±0.46)％.The ratio of Tc17/CD4+CD8+ in the lung of C groups( 1.62±0.53) ％ and in the skin of B and C groups [ (1.70±0.70) ％,( 1.63±0.63 ) ％ ]was significantly increased compared with A group [ ( 1.00±0.47 ) ％,( 1.1 1 ±0.34 ) ％ ],all P＜0.05.Compared with the A group,the mRNA levels of IL-17A,RORγt in skin of B and C groups,and in lung of C group were higher and the levels of IL-17 in serum was significantly increased,all P＜0.05.Th17 cells and the levels of IL-17 in blood were positive correlation with dermal and pulmonary inflammation,fibrosis and H YP contents,all P＜0.01.The frequency of Th17 and Tc17 cells in skin and lung respectively had a positive correlation with dermal and pulmonary inflammation,the score of fibrosis,and HYP contents of skin and lung,all P＜0.01.Conclusion Th17 and Tc17 cells were significantly increased in the peripheral blood,skin and lung of a murine model of SSc,and Th17 cells is dominated.They correlated with the inflammation and fibrosis of skin and lung,and may participate in the pathogenesis of SSc through secrete IL-17.