Metformin regulate the balance of Th17/regulatory T cells and expression of serum cytokines through AMPK-mTOR signaling pathway in collagen-induced arthritis / 中华风湿病学杂志

ABSTRACT

Objective To evaluate therapeutic effects of metformin on the expression of serum cytokines,balance of splenic Th17/regulatory T cells (Treg) and expression of splenic AMPK-mTOR in collagen-induced arthritis (CIA) rats,and the mechanism thereof.Methods The rat model of CIA was established by injecting bovine type Ⅱ collagen.Forty rats were randomly divided into five groupsthe CIA model group(sterile water by gavage),Met-30 mg/kg group (metformin 30 mg ·kg-1 ·d-1 by gavage),Met100 mg/kg group(metformin 100 mg ·kg-1 ·d-1 by gavage),Met-300 mg/kg group(metformin 300 mg ·kg-1 ·d-1 by gavage) and control group (sterile water by gavage).The hind paw volume was recorded once a week.The serum level of cytokines,tumor necrosis factor (TNF)-α,interleukin (IL)-1β,IL-6,and IL-17,were measured by enzyme linked immunosorbent assay (ELISA) 35 days after the initial immunization.The quantity of Th17 and Treg cells were examined by flow cytometry.The expression of AMPK,p-AMPK,mTOR and p-mTOR were examined by western blotting.One-way analysis of variance was used to evaluate the experimental data.Results The values of hind paw volume were decreased on the 35 d of the initial immunization in the Met100 mg/kg [(2.43±0.37) ml,t=2.97,P＜0.05] and Met-300 mg/kg groups [(2.58±0.21) ml,t=2.96,P＜0.05] than those of CIA model group (2.97±0.23) ml.The serum levels of TNF-α,IL-1β,IL-6 and IL-17 on the 35-d after the initial immunization were significantly lower in the metformin therapeutic groups [Met-300 mg/kg group TNF-α (104±8) pg/ml,t=42.77,P＜0.05;IL-1β (183±24) pg/ml,t=60.457,P＜0.05;IL-6 (19.3±2.8) pg/ml,t=53.62,P＜0.05;IL-17 (64.5±6.7) pg/ml,t=47.92,P＜0.05] than those of the CIA model group [TNF-α (246±8) pg/ml;IL-1β (1 336±40) pg/ml;IL-6 (87.0±5.1) pg/ml;IL-17 (282.3±6.8) pg/ml].The quantity of Th17 and Treg cells were significantly different in the Met-300 mg/kg group than those of the CIA model group 35 d after the initial immunization [Th17(6.57±0.39) vs (9.89±0.53),t=8.74,P＜0.05;Treg (7.60±0.45) vs (3.94±0.61),t =8.37,P＜0.05].The expression of p-AMPK on the 35 d after the initial immunization in the metformin therapeutic groups was significantly higher than in the CIA model group(P＜0.05),and the expression of p-mTOR was significantly lower (P＜0.05).Conclusion Metformin can significantly inhibit the serum levels of TNF-α,IL-1β,IL-6 and IL-17 in CIA model rats,and regulate the balance of Th17/Treg through AMPK-mTOR signaling pathway.