Expression Of Interleukin-21in The Lungs Of Mice With Emphysema And Its Effects On The Differentiation Of Cd4~+T Cell

Objective To evaluate the expression of interleukin (IL)-21in a cigarette smoke-induced mice model of emphysema and investigate its impact on the differentiation of CD4+T cell.Methods Twenty male Balb/c mice were randomly divided into two groups:control group, smoke-exposed group. Morphological changes were evaluated by mean linear intercepts and destructive index. The proportion of CD4+IL-21R+T cells in lungs of mice was determined by flow cytometry. The levels of IL-21in lungs of mice were analyzed by enzyme-linked immunosorbent assay (ELISA). Fresh lung mononuclear cells were isolated from smoke-exposed group, and were divided into two groups:blank group, co-culture group. Two groups were cultured in medium with or without IL-21for24h,48h. The proportion of Th1and Th17cells in cell culture medium was determined by flow cytometry.Results Mean linear intercepts and destructive index in smoke-exposed group ((48.6±4.8) μm and44.9±2.8) were significatly higher as compared to control group ((32.4±4.0) μm and28.1±2.1, all P<0.05). In lungs, the percentage of CD4+IL-21R+T cells in smoke-exposed group (4.1%±1.5%) were significantly increased than that in control group (1.4%±0.4%)(P<0.05). The levels of IL-21in lung of smoke-exposed group ((851±28) ng/L) were higher than control group ((415±39) ng/L, P<0.05). In lungs, the levels of IL-21had positive correlations with mean linear intercepts and destructive index (r=0.736and0.738, all P<0.05). The percentage of CD4+IFN-y+and CD4+IL-17+T cells in cell curture medium of co-curture groups for24h [(7.4±1.6)%and (4.2±1.5)%] was significantly increased as compared with that in blank group [(3.9±1.1)%and (2.2±0.7)%], all P<0.05. The percentage of CD4+IFN-γ+and CD4+IL-17+T cells in cell curture medium of co-curture groups for48h [(18.1±3.2)%and (12.5±3.3)%] was significantly increased as compared with that in blank group [(11.4±0.9)%and (5.8±1.5)%], all P<0.05.Conclusions An up-regulated expression of IL-21in lungs of cigarette smoke-induced emphysema mice is detected, and accompanied by CD4+T cells increased expression of IL-21R. IL-21can make the CD4+T cells to Th1(CD4+IFN-γ+) cells and Th17(CD4+IL-17+) cells differentiation by inducing CD4T T cells expressed IFN-γ、IL-17. And it maybe participate in the formation and development of emphysema by this way.