The Expression Of T Regulatory Cells In BALF And PB Of Smoke Exposure And Smoking Cessation Rats

Objective To study the expression of T regulatory cells(Treg cells) in bronchoalveolar lavage fluid(BALF) and peripheral blood(PB) of smoke exposure and smoking cessation rats.Methods 50 healthy male Wistar rats were randomly divided into five groups: 12-week normal control group(group A, n =10), 24-week normal control group(group B, n=10),12-week smoking group(group C, n=10), smoking-cessation group(group D, n=10), 24-week smoking group(group E, n=10). Group C, group D , group E were exposured to cigarettes for 12 weeks. At 12 week, group A and group C were sacrificed, group D was smoking cessation for 12 weeks and group E was continued to smoke exposure . At 24 week, group B, group D and group E were sacrificed. Pathomorphological changes of the small airway were analyzed. Collected the cells in BALF were analyzed by absolute and differential cell counts. Enzyme linked immunosorbent assay(ELISA) was used to detect the levels of IFN-γ,IL-4, IL-8,TNF-α.Using flow cytometry to determine Foxp3+Treg cell populations and reverse transcription- polymerase chain reaction(RT-PCR) to assay mRNA expression for Foxp3.Result (1)Compared with group A and group B, the airway inflammation score of group C, group D, group E were increased significantly(P<0.01). Compared with group C, the airway inflammation score of group D, group E were both increased(P<0.01), especially group E. (2) Compared with group A and group B, the levels of IFN-γ,TNF-α,IL-8 in group C, group D, group E were increased(P<0.01), and the levels of IL-4 was decreased. The levels of IFN-γ,TNF-α,IL-8 were no difference between group C and group D. The levels of IFN-γ,TNF-α,IL-8 were higher in group E than these in group C and group D. (3)The ratio of Foxp3+ Treg cells in BALF was higher in group C, group D, group E compared with group A and group B(P<0.01). There were no differences in the ratio of Foxp3+ Treg cells among group C, group D, group E. It was revealed no differences in the ratio of Foxp3+ Treg cells in peripheral blood among all groups. (4) There were increased in the expression of Foxp3 mRNA in group C, group D, group E compared with group A and group B(P<0.01). It was revealed no differences in the expression of Foxp3 mRNA among group C, group D, group E. There were no differences in the expression of Foxp3 mRNA in peripheral blood among all groups.Conclusion (1) It showed there exist airway inflammation induced by Th1/Tc1 in smoke-esposured rats and the expression of Treg cells was increased in BALF. (2)Upon smoking cessation , the above-mentioned airway inflammation still persist but it was lighten than that in rats which were continued to smoke exposure. And the expression of Treg cells in BALF was not decreased. (3)Treg cells probably could inhibits airway inflammation.