Investigation Of The Expression Of Foxp3 And TGF-β1 In Collagen-induced Arthritis In Rat

Objective Through the detection of the specific expression of Foxp3mRNA of CD4+CD25+ regulatory T cells in the spleen and the expression of Transforming Growth factorβ1(TGF-β1) in the spleen and synovium, to explore the role of CD4+CD25+ regulatory T cells and its mechanism in collagen-induced arthritis in wistar rat.Methods The wistar rats were randomly divided into control and experimental groups. The Wistar rats were immunized with emulsified bovine typeⅡcollagen (CCⅡ) in complete Freund′s adjuvant by intradermal injection to induce the rat model of collagen-induced arthritis (CIA) on day 1 and day 14, while the control groups were injected with the same amount of saline. The two groups were killed at day 14, 30 and 45 after immuned. The expression of Foxp3mRNA in the spleen was detected by reverse transcription polymerase chain reaction, and the expression of TGF-β1 in the spleen and synovium was detected by immunohistochemical analysis.Results Foxp3mRNA in the spleen was significantly up-regulated in model groups compared with control groups(P<0.01), and reached the top during the stage of acute inflammation with significantly difference between the groups of day 14 and day 30. After that, its expression lowered with still higher expression compared with the expression at day 14 and its control groups. TGF-β1 in the spleen was significantly up-regulated in model groups compared with control groups(P<0.01), and lowered during the stage of acute inflammation with significant difference between the day 14 and day 30. After that, its expression increased significantly compared with the expression at day 14. TGF-β1 in synovial membrane was significantly up-regulated in model groups compared with control groups(P<0.01), and reached the top during the acute stage of inflammation with significant difference between the day 14 and day 30. After that, its expression was lowered with significant difference between the day 30 and day 45, but had no difference between the day 14 and day 45(P>0.05) .Conclusions The function of CD4+CD25+regulatory T cells was lowered in model groups. Its lowered function was caused by the dysfunction of Foxp3 in the CD4+CD25+regulatory T cells. This may cause insufficiently TGF-β1 produced, and cannot suppress the autoimmune response sufficiently in CIA. Further research is needed to show if the gene of Foxp3 is defective. The different expression of TGF-β1 in the spleen and synovium suggest that it have double role in CIA.