[Roles of tyrosine hydroxylase expressed by CD4+ T cell subsets in collagen type II-induced arthritis]

We used an animal model of collagen-induced arthritis (CIA) to study changes and roles of tyrosine hydroxylase (TH) expressed by CD4+ T cell subsets, and then explore the relationship between CD4+ T cell subset-derived catecholamines and inflammatory responses in CIA.

Thirty-six male DBA/1 mice were randomly divided into control group, CIA model group (day 35) and CIA model group (day 55) (n = 12). CIA model was induced by type II collagen (CII) in DBA/1 mice. On the 35th and 55th day following primary immunization, the joints of the mice were observed for clinical score of swelling and the level of anti-CII IgG antibody in serum was examined. Expression of specific transcription factors and cytokines of Th1, Th17, Th2 and Treg cells and TH in mesenteric lymph nodes was measured by means of Western blot. The changes of TH expressed by CD4+ T cell subsets in mesenteric lymph nodes were determined by flow cytometry.

Clinical score and anti-CII antibody level increased in CIA compared with that in intact mice. Specific transcription factors and cytokines expressed by Th1 and Th17 cells were upregulated and cytokines expressed by Th2 and Treg cells were downregulated in mesenteric lymph nodes in CIA mice. Expression of TH was upregulated and the increased expression of TH in CD4+ T cells was attributed to Th1 and Th17 cells in mesenteric lymph nodes of CIA.

The increase in catecholamines from CD4+ T cell subsets in mesenteric lymph nodes of CIA may be related to inflammatory alleviation in CIA progression.