| Objective:To explore the effects of acrylonitrile on T lymphocyte subsets, expression of toll-like receptor 4 and related cytokines in rats and to understand the impact of changes in Nrf-2、ROS、HSP70 mRNA on oxidative stress and immunity.Methods:Sprague-Dawley rats were randomly divided into 4 dose groups,8 male and 8 female rats in per group. Rats in each group were respect-tively given a single dose of 0,5,10 and 20mg/kg acrylonitrile by gavage, once a day,5 days a week, for 13 weeks. Blood and spleen T lymphocyte subsets were detected by flow cytome-try. The mRNA expression of Nrf-2, HSP70, ROS, TLR4, IL-1β and TNF-a was analyzed by real-time quantitative PCR.The protein expression of TLR4 was evaluat-ed by Western blot.Results:①Compared with control group,weight of the rats in experimental groups showed a downward trend, and weight of female rats in 10,20mg/kg group and male rats in 20mg/kg group were significantly decreased (P<0.05). Organ coefficient of spleen showed a upward trend, and organ coefficient of female rats in 5, 10,20mg/kg group and male rats in 20mg/kg group were significantly increased (P<0.05). We found that female rats were more sensitive than male rats in the change of body weight and spleen coefficient. Body weight of female rats at the dose of 10mg/kg decreased significantly, while no significant change in male rats. The spleen coefficient of female rats showed increasing trend from the dose 5mg/kg, while male rats only in 20mg/kg group. The main pathological changes of rats in the 20 mg/kg group were cloudy swelling and hydropic degeneration in liver, pulmonary bronchiolitis, perivasculitis and compensatory emphysema in lung, vacuolar degene-ration in brain hippocampal neurons, mallory bodies scattered and focal hyperplasia of glial cell, seminiferous gap widened, spermatogenic cells decreased.② Compared with control group,the percentages of blood CD3,CD4 T cells in 20mg/kg female group and CD4/CD8 ratio in 5,10 and 20mg/kg female group were significantly decreased, CD8 T cells in 5,10 and 20mg/kg female groups was significantly increased(P<0.05 or P<0.01); Blood CD3 T cells in 5mg/kg male group, and CD4 T cells, CD4/CD8 ratio in 20 mg/kg male groups were lower than that of control group, CD8 T cells in 20 mg/kg male groups was significantly increased (P<0.05 or P<0.01). Spleen CD4 T cells and CD4/CD8 ratio in 20mg/kg female group were decreased significantly,CD8 T cells was significantly increased (P<0.05 or P<0.01). Spleen CD4 in 20mg/kg male group and CD4/CD8 ratio in 10,20mg/kg male groups were also significantly decreased, and CD3, CD8 T cells in 20mg/kg male group were significantly increased (P<0.05 or P<0.01)③ Compared with control group, the TLR4 protein and mRNA expression of the rats in experimental groups showed a downward trend. The expression of TLR4 mRNA was lower in 5,10 and 20mg/kg male groups and lOmg/kg female group (P<0.05 or P<0.01). TLR4 protein in 5mg/kg female group and 20 mg/kg male group was significantly lower than that of control group (P<0.05)④ The expression level of IL-1β mRNA was significantly decreased in 5,10 and 20mg/kg female group and 5,10mg/kg male group (P<0.05 or P<0.01).The expre-ssion TNF-a mRNA was lower in 10,20mg/kg female groups and 5,10 mg/kg male groups (P<0.01)⑤Compared with control group, Nrf-2 mRNA expression of the rats in experimental groups showed a downward trend, both female and male rats in 5,10, 20mg/kg group were significantly decreased (P<0.05 or P<0.01), the decreasing of Nrf-2 mRNA expressiof female rats in 5mg/kg group was most evident and the same of male rats in 20mg/kg group, there are differences in male and female response. ROS mRNA expression of female rats in 10,20mg/kg group and male rats in 5,10, 20mg/kg group showed a downward trend (P<0.01). Expression of ROS mRNA in female rats were decreased with dose increasing, but male rats showed two high points of reaction:5mg/kg and 20mg/kg group decreased more than 10mg/kg group. Compared with control group,HSP70 mRNA expression of the rats in experimental groups showed a downward trend, both female and male rats in 5,10,20mg/kg group were significantly decreased (P<0.05 or P<0.01). The decreasing trend in male and female rats was more obvious in 10mg/kg group.Conclusion:Acrylonitrile can affect the animal’s growth, with organ toxicity in subchronic exposure. 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 decreased 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. The expression of ROS, Nrf-2 and HSP70 mRNA in spleen was also significantly decreased, indicating that this may weaken the level of oxidative stress and anti-oxidation capacity. |
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