Electroacupuncture Protects against Articular Cartilage Erosion by Inhibiting Mitogen-Activated Protein Kinases in a Rat Model of Osteoarthritis

Abstract

Objective The therapeutic effects of electroacupuncture (EA) on osteoarthritis (OA) are well documented; however, the precise mechanisms of action have not yet been fully elucidated. The present study aimed to investigate the effect of EA on cartilage in an experimental animal model of OA induced by anterior cruciate ligament transection (ACLT) and to examine for concomitant changes in the expression of mitogen-activated protein kinases (MAPKs) in the articular cartilage. Methods Thirty-three-month-old male Sprague Dawley rats were randomly divided into the following three groups (n=10 each): sham operated group (Control group), ACLT without treatment (ACLT group), and ACLT with EA treatment (ACLT+EA group). One week after ACLT, rats in the ACLT+EA group received 12 weeks of EA treatment. Histological analysis and quantitative real-time PCR were used to investigate the effects of EA on cartilage morphology (quantified using modified Mankin scores) and expression of MAPKs (p38, c-Jun N-terminal kinase (c-Jun), and extracellular signal-regulated kinase (ERK)1), respectively. Results ACLT produced coarse cartilage surfaces, fibrous degeneration, and fissuring, all of which were suppressed by EA treatment. Although Mankin scores in the ACLT+EA group were significantly higher compared to the Control group (p<0.01), they were significantly lower than the (untreated) ACLT group (p<0.01). The increase in mRNA expression of p38, c-Jun, ERK1, and matrix metalloproteinase (MMP)-13 observed in cartilage after ACLT was significantly inhibited by EA. Conclusions EA appears to prevent the degeneration of articular cartilage, at least partly through regulation of MMP-13 and inhibition of MAPKs in the cartilage of rats with ACLT-induced OA.