Effects of Qingli Gandan decoction on IL-23/IL-17 in rats with experimental autoimmune uveitis

Abstract In this study, through animal experiments, we investigated the effects of Qingli Gandan decoction on the IL-23/IL-17 signalling pathway and the expression of CD4+/IL-17A+ cells in EAU rats. We then predicted the potential mechanisms of the action. First, Lewis rats were divided using the random number table method into a (1) control group, (2) model group and (3) TCM group. The TCM group was given a Qingli Gandan prescription by gavage after an intervention model. Next, blood, aqueous humour and vitreous were collected from each group on days 4, 8, 12, 16 and 20 after immunisation. An enzyme linked immunosorbent assay (ELISA) was used to detect the protein concentrations of IL-17 and IL-23 in a serum, aqueous humour and vitreous of rats on different immunisation days, and the percentage of CD4+/IL-17A+ cells in rat spleen was detected by flow cytometry. The peak concentration of serum IL-17 protein in group 3 was statistically lower than that in group 2 (P < 0.05) on days 4, 8 and 12 of immunisation. However, the peak concentration of serum IL-23 protein in group 3 was statistically lower than in group 2 (P < 0.05) on days 8 and 12 of immunisation; in addition, on days 8 and 12, the protein concentrations of IL-23 and IL-17 in the aqueous humour group 3 were all lower than those in group 2. On days 4, 8 and 12, the protein concentrations of IL-23 and IL-17 in vitreous in group 3 were significantly lower than those in group 2. We found that the proportion of CD4+/IL-17A+ cells in the groups 2 and 3 increased on day 8 compared with group 1 (P < 0.05). The proportion of CD4+/IL-17A+ cells decreased in group 3 compared with group 2 (P < 0.05).At last, we think Qingli Gandan can reduce the onset of EAU in rats and treat it, presumably because of inhibiting the IL-23/IL-17 axis. It may inhibit the expression of CD4+/IL-17A+ cells and play a role in inhibiting the IL-23/IL-17 signalling pathway.