Effect of CD4+ CD25+ regulatory T cells and T helper type 17 cells in septic rats

Abstract

Objective To investigate the roles of CD4+ CD25+ regulatory T cells(Treg)and T helper type 17(Th17)cells in inflammatory response in septic rats. Methods A total of 110 healthy male Sprague-Dawley rats(250-300 g)were randomly divided into 3 groups:normal control group,sham group and cecal ligation and puncture(CLP)group.The rat models of sepsis were established by improved CLP.Flow cytometric analysis was performed to detect the percentage of CD14+ T cell, Th17 cells and Treg cells subpopulation.Expressions of proinflammatory cytokines[interleukin(IL)-6,IL-10,tumor necrosis factor(TNF)-α, transforming growth factor(TGF)-β, IL-17] were measured by using enzyme-linked immunosorbent serologic assay. Results Compared with sham group,(1) While the spesis becoming worse, the rats were immunological inhibition, the expression levels of leucocyte antigen-DR(19. 63±7. 56)% lower than 30% and the rate of IL-10/TNF-α(27. 41±7. 04 vs.6. 63±2. 60, P< 0. 01)significantly up-regulated.(2) After 96 hours, the proportions of Treg cells[(11. 91±3. 88)% vs.(6. 57±2. 60)%, P< 0. 01]and Th17 cells[(5. 14±0. 29)% vs.(2. 85±0. 07)%,P<0. 01]in sepsis group were significantly higher.(3)After 96 hours, the expression levels of IL-6[(42. 31±15. 89) ng/L vs.(6. 32±3. 18) ng/L, P< 0. 01], IL-10 [(69. 89±20. 78)ng/L vs.(13. 58±5. 37) ng/L, P< 0. 01], TNF-α[(5. 03±3. 10) ng/L vs.(2. 77± 1. 10)ng/L, P<0. 01], TGF-β[(4. 99±2. 01)ng/L vs.(1. 88±1. 07)ng/L,P<0. 01],IL-17[(92. 77 ±11. 64)ng/L vs.(7. 58±2. 30)ng/L, P<0. 01]were significantly up-regulated in sepsis group. Conclusion While the spesis becoming worse, the rats were immunological inhibition.Aberrant activation of Th17 cells and Treg cells might be involved in pathogenesis in sepsis.The changes of cytokine environment in sepsis may be one of the factors causing the imbalance of Treg cells/Th17 cells. Key words: CD4+ CD25+ regulatory T cells; T helper type 17 cells; Sepsis