Immunosuppressive effects of an ethyl acetate extract from Urtica dentata Hand on skin allograft rejection

Abstract

Aim of the study To investigate the immunosuppressive effects of HPLC qualitied ethyl acetate extract (EAE) from Urtica dentate Hand on skin allograft rejection in a murine model. Materials and methods Allo-skin transplantation model was established by placing skin allograft of C57BL/6 mice in the wound bed which was on the back of Balb/c mice. We used FACS to study the effects of EAE on dendritic cells (DCs) maturation and CD4 +CD25 +T regulatory cells (Tregs) differentiation. We also studied spleen lymphocyte proliferation and T-bet gene expression in DCs. Concentration of Th1/Th2 cytokines was monitored as markers of Th1/Th2 responses by ELISA. Results A significant prolongation of skin allografts survival was observed as a dose-dependent manner in the animals treated with EAE. By FACS, we found that treatment with EAE (200 mg kg −1) resulted in an immature statement of DCs and stimulated the differentiation of CD4 +CD25 +Tregs. Additionally, the expression of T-bet gene and the proliferation of spleen lymphocytes were efficiently abated in EAE treated mice. Comparing to the model control, EAE-treated recipients showed a significant down-regulation ( P < 0.01) of Th1 cytokines (IL-2, IFN-γ) and an obviously increase ( P < 0.01) of Th2 cytokine (IL-10) in the serum, which presented in a dose-related way. Conclusions The anti-allograft rejection effect of EAE by enhancing CD4 +CD25 +Tregs differentiation and sustaining DCs immaturation makes EAE to be a possible choice for treating autoimmune diseases in a way of inducing a stable immunological tolerance state.