Catgut Implantation at Acupoints has an Immunosuppressive Effect on Autoimmune Uveitis by Regulating Th1/Th17 Lymphocytes

Abstract

Catgut implantation at acupoints (CIA) has a long history as a medical treatment for a wide variety of diseases, including autoimmune diseases. However, the effect and mechanism of this therapy in autoimmune uveitis is still largely unknown. The aim of this study was to explore the immunity-inhibitory effect of CIA in an experimental autoimmune uveitis (EAU) rat model. EAU was established in Lewis rats by the injection of IRBP1177–1191 peptide. The rats were randomly divided into control and CIA groups. Phenotypic and histological assessments were performed days 9, 13, 18, 23 post-immunization. The percentage of Th1 and Th17 lymphocytes isolated from lymph nodes were determined by flow cytometry. The expression of IL-17 and IFN-γ was detected by real-time quantitative PCR and enzyme-linked immunosorbent assay (ELISA). In the CIA group, delayed mild inflammation was observed. Pathological investigation found alleviated infiltration of lymphocytes and ocular damage. Flow cytometry showed significantly decreased Th17 lymphocytes at day 9, 13, and 18 post-immunization (P<0.05) and no significant changes at day 23 post-immunization (P=0.868) after CIA. The Th1 lymphocytes were significantly decreased at day 13 and 18 post-immunization (P<0.05) and comparable at day 9 (P=0.111) and 23 (P=0.551) post-immunization in the CIA group. IL-17 and IFN-γ mRNA levels were notably decreased at day 9, 13 and 18 post-immunization (P<0.05) and showed a downward trend at day 23 post-immunization, although with no significance (P=0.080 and P=0.137, respectively) after CIA. Serum IL-17 and IFN-γ levels in the CIA group were significantly decreased at day 9, 13 and 18 post-immunization (P<0.05) and were comparable at day 23 post-immunization (P=0.078 and P=0.979, respectively). Ocular inflammation was markedly inhibited after catgut implantation at Pishu (BL20) and Shenshu (BL23) acupoints in an EAU rat model. Moreover, CIA reduced Th1 and Th17 lymphocytes and the expression IFN-γ and IL-17.