RESUMEN
Background:Dexamethasone can protect mice against the acute inflammatory liver injury by inhibiting innate immune cell function. However,the roles of T cell in this protective effect remain unknown. Aims:To investigate the regulatory effect of dexamethasone on T cell immune response in acute inflammatory liver injury. Methods:Six male C57BL/ 6J mice were randomly divided into 2 groups. One hour before induction of acute inflammatory liver injury by lipopolysaccharide, dexamethasone 5 mg/ kg and PBS were given intraperitoneally in experimental group and model group,respectively. All the mice were sacrificed 12 hours after model construction. The clinical score and liver function parameters were assessed;splenic mononuclear cells were isolated for measurements of T cell activation,as well as cytokine expression,secretion, and transcriptional factor expression for different T-cell subsets. Results:Clinical score and serum levels of transaminase were significantly lower in experimental group when compared with the model group. Meanwhile,percentage of CD44 +CD62L - T cells(i. e. activated or memory T cells)from spleen was significantly decreased in experimental group. Among splenic T cell population,expression and secretion of IFN-γ,a Th1-type cytokine,was decreased;expression and secretion of IL-4,a Th2-type cytokine,percentage of regulatory T cells(Treg cells),and ratios of Th2 / Th1 and Treg/ Th1 were increased;transcriptional factor specific for Th1 cells was down-regulated,and those for Th2 and Treg cells were up-regulated. Conclusions:Dexamethasone inhibits T cell activation and directs the reciprocal T cell lineage differentiation (repressing Th1 cell differentiation,promoting Th2 and Treg cell differentiation),which may contribute to the protection against acute inflammatory liver injury.