Experimental study on the expression of T cells and cytokines in the regulation of autoimmune dry eye

AIM: To investigate the role of regulatory T cells in the pathogenesis of autoimmune dry eye and to analyze the expression of endogenous regulatory T cells and related cytokines in the lacrimal system to provide a more effective treatment for autoimmune dry eye disease treatment programs. <p>METHODS: Rabbit lacrimal gland epithelial cells isolated and cultured for a period of time were separately cultured and mixed with isolated peripheral blood lymphocytes in a ratio of 1: 1 and cultured with 5-Bromo-2-deoxyUridine(BrdU)to detect the proliferation of peripheral blood lymphocytes, and the activated autologous peripheral blood lymphocytes were transferred to donor rabbits via ear vein. The rabbits were used as the rabbit model of autoimmune dry eye and the normal rabbits which did not induce the disease as the control group. Before and after the experiment, tear film rupture time and tear secretion at 2,4,6,8wk,were observed. At 4 wk after the transfusion the rabbits were sacrificed for the collection of bilateral upper and lower lacrimal gland and conjunctiva, and pathological HE staining, and then extract the total RNA in lacrimal gland. The expression of IL-17, TNF-α, IL-6 and TGF-γ was detected. <p>RESULTS: BrdU detected peripheral lymphocyte proliferation rate of 3.72. Compared with the normal group, the time of rupture of the tear film decreased(<i>P</i><0.05), and the tear of the model group was significantly lower than that of the control group(<i>P</i><0.05). The expression of IL-17, TNF-α, TGF-γ and IL-6 in the model group were significantly higher than those in the control group(<i>P</i><0.05). The expression of IL-10 and TGF-β was significantly lower than those of the control group(<i>P</i><0.05). The ratio of CD4⁺ CD2⁺ Treg cells in lacrimal gland tissue and spleen was higher in control group. The proportion of CD4⁺CD25⁺ Treg cells in model group decreased(<i>P</i><0.05). <p>CONCLUSION: IL-17, TNF-α, IL-6 and TGF-γ play important roles in inflammatory reaction of lacrimal gland and the immunodepression active by CD4⁺CD25⁺Treg cells decreases when the rabbit model of dry eye is involved