Abstract: Objective: To investigate the effects of vitamin A and budesonide on peripheral blood T-lymphocyte subsets and CD4⁺CD25⁺ Treg cells in rat asthma model,which provide the experimental basis for vitamin A in the prevention and treatment of bronchial asthma.Methods: Forty-two adult female SD rats were divided into three groups,the budesonide group,vitamin A group and asthma group.There were 14 rats in each group.The peripheral blood was conducted to determinate T-lymphocyte subsets and CD4⁺CD25⁺ Treg by flow cytometry.Results: After the 4th of stimulation,CD3⁺T cell and CD4⁺CD25⁺ Treg cells in vitamin A group were significantly higher than those in budesonide group.CD3⁺CD8⁺T cell in vitamin A group was significantly lower than that in asthma group(P<0.05).CD4⁺CD25⁺ Treg cells of budesonide group was significantly lower than that in asthma group(P<0.01).After the 5th of stimulation,CD4⁺CD25⁺ Treg cells in budesonide group was significantly lower than that in asthma group(P<0.05).Conclusions: Inhalation of vitamin A can reduce inflammation in asthmatic rats,which may be associated with the increases of peripheral blood CD3⁺T cells and CD4⁺CD25⁺ Treg cells cells and the decrease of CD8⁺T cells.