[Dynamic changes of Th1/Th2 cytokines in lung tissue of experimental silicotic rat]

To determine the role of Th1 / Th2 cytokines in lung tissue of experimental silicotic rat.

84 healthy SPF male SD rats were randomly divided into silica exposure group and control group. Silica suspension at 1 m L( 100 mg / m L) was administrated once by injection of non-exposure bronchus while equal amount of saline was instilled to the rats in control group, rats were sacrificed at 1~(st) day, 1~(st), 2~(th), 3~(th), 6~(th), 9~(th) and 12 ~(th) week after instillation. Cytokines in lung tissue were detected by ELISA.

Compared with healthy control, the levels of TNF-α was increased at each point in silica exposure group( P < 0. 05). The IFN-γ in silica exposure group was increased in 1~(st) day, 1~(st) and 2~(th) week( P < 0. 05). There was no significant difference about IL-18 between silica exposure group and control group. The IL-4 in silica exposure group was decreased in 1~(st)week, and increased in 9thweek and 12~(th) week( P < 0. 05). The IL-10 in silica exposure group increased in 6~(th) and 9~(th) week( P < 0. 05). The ratio of Th1 / Th2 of silica exposure group was increased in 1~(st)day, 1~(st)and 2~(th) week( P < 0. 05).

The expression of Th1 cytokines are kept at a high level, Th2 cytokines decrease firstly and increase subsequently. Differential expressions of cytokines play an important role in development of silicosis.