Inhibitory effects of Longdan Xiegan Decoction on Notch signaling in rats with experimental autoimmune uveitis / 眼科新进展

ABSTRACT

Objective To investigate the effects of Longdan Xiegan Decoction on the expression of Notch signaling-related genes in rats with experimental autoimmune uveitis (EAU).Methods Totally 24 Lewis rats were randomly divided into normal control group,EAU model group and Longdan Xiegan Decoction treatment group.A rat model of EAU was established in the EAU model group and Longdan Xiegan Decoction treatment group,followed by intragastrical administration of Longdan Xiegan Decoction in the latter group after successful modeling.On day 12 after different treatments,the spleen and lymph nodes were isolated from rats of all the three groups for the collection of CD4 + T ceils,and the levels of both Th17 and Treg cells were analyzed by flow cytometry to calculate the ratio of Th17 to Treg cells.Meanwhile the levels of Notch1,Notch2,Notch3,Notch4 mRNAs expression were monitored by qRT-PCR.Moreover,the expressions of Notch signaling-related proteins were further detected using ELISA technique.Results Flow cytometry showed increased Th17 cell level but decreased Treg cell level in the EAU model group when compared with the normal control group.However,after treatment with Longdan Xiegan Decoction,the Th17 level was decreased,whereas the Treg level was increased,and the ratio of Th17 to Treg gradually restored to equilibrium when compared to EAU model group.qRT-PCR results showed that the expression levels of Notch1,Notch2 and Notch4 mRNAs in Longdan Xiegan Decoction treatment group were significantly higher than those in the normal control group (all P ＜ 0.01),but lower than those in EAU model group on day 12 after treatment (all P ＜ 0.01),without Notch 3 expression in the spleen and lymph nodes.In addition,Notch 1,Notch 2 and Notch 4 protein levels of the spleen and lymph nodes in Longdan Xiegan Decoction treatment group showed the similar tendency as compared to those of Notch 1,Notch 2 and Notch 4 mRNAs (all P ＜ 0.01),and the expression of Notch 3 protein was still not observed.Conclusion Longdan Xiegan Decoction can effectively relieve the imbalance of Th17/Treg cells in EAU rats,and its mechanism may involve the differentiation of naive CD4+ T cells into Th17 and Treg cells,which is regulated by Notch signaling.