[The effects of acrylonitrile on T lymphocyte subsets and expression of toll-like receptor 4 in rats].

Objective: To explore the effects of acrylonitrile on T lymphocyte subsets, expression of toll-like receptor 4 and related cytokines in rats.

Methods: Sixty-four Sprague-Dawley rats were randomly divided into 4 female groups and 4 male groups, and there were 8 rats in each group. Rats in each group were respectively given a single dose of 0, 5, 10 and 20 mg/kg acrylonitrile by gavage, once a day, 5 days a week, for 13 weeks. Blood and spleen T lymphocyte subsets was detected by flow cytometry, the mRNA expression of TLR4, IL-1β and TNF-α was analyzed by real-time quantitative PCR, the protein expression of TLR4 was evaluated by Western blot.

Results: Compared with control group, the percentages of blood CD3, CD4 T cells in 20 mg/kg female group and CD4/CD8 ratio in 5, 10 and 20 mg/kg female groups was significantly decreased, CD8 T cells in 20 mg/kg group was significantly increased (P < 0.05 or P < 0.01), blood CD3 T cells in 5 mg/kg male group, CD4 T cells and CD4/CD8 ratio in 20 mg/kg male groups were lower than that of control group, CD8 T cells in 20 mg/kg make group was significantly in oreased (P < 0.05 or P < 0.01). Spleen CD4, CD8 T lymphocyte percentages and CD4/CD8 ratio in 20 mg/kg female group decreased significantly, CD8 T cells in 20 mg/kg male group was significantly increased (P < 0.05 or P < 0.01), spleen CD3, CD4, CD8 T cells in 20 mg/kg male group and CD4/CD8 ratio in 10, 20 mg/kg male groups was also significantly decreased, CD3 T cells in 20 mg/kg and CD8 T cells in 10, 20 mg/kg male groups were significantly increased (P < 0.05 or P < 0.01) (TLR4 mRNA was lower expressed in 5, 10 and 20 mg/kg male groups and 10 mg/kg female group (P < 0.05 or P < 0.01), and TLR4 protein in 5 mg/kg female group and 20 mg/kg male group was significantly lower than control group (P < 0.05). The expression level of IL-1β mRNA was significantly decreased in 5, 10 and 20 mg/kg female group and 5, 10 mg/kg male group (P < 0.05 or P < 0.01), TNF-α mRNA was lower expressed in 10, 20 mg/kg female groups and 5, 10 mg/kg male groups (P < 0.01).

Conclusion: Acrylonitrile may lead to the changes of CD3, CD4, CD8 T lymphocyte percentages and CD4/CD8 ratio in rat blood and spleen, and also significantly effected the expression level of TLR4 mRNA and protein together with the secretion of IL-1β, TNF-α. This may cause effects on the cellular immune function.