BACKGROUND: The aim of this study was to investigate the mechanisms underlying the potential effects of hydrogen-rich water (HW) on articular cartilage in a rat osteoarthritis (OA) model.

MATERIAL AND METHODS: A rat model of OA was established using the modified Hulth method, and rats were forced to exercise for 30 min every day 1 week after surgery for 7 weeks. Mankin’s method was used to score the severity of OA. The animals were assigned into the OA group, OA+HW group, and sham operation group. After 8 weeks, the animals in the OA group had a Mankin score >8 points, and HW was administered into the knee joint. After 2 weeks of treatment, articular cartilage was obtained for pathological examination, consisting of hematoxylin and eosin, toluidine blue, and Hoechst staining, as well as quantitative real-time PCR and Western blot analyses. This combination of pharmacological and molecular biological analyses was performed to examine the mechanism underlying the protective effect of HW on articular cartilage.

RESULTS: The antioxidant effects of HW suppressed oxidative damage, which may have aided the inhibition of ECM-degrading enzymes (MMP3, MMP13, ADAMT4, and ADAMT5), the upregulation of Col II and aggrecan expression, and the downregulation of COX-2, iNOS, and NO expression. The results of HE staining indicated intra-articular treatment of HW attenuated cartilage degradation. However, Hoechst staining in the OA group indicated the nuclei of the fragmented chondrocytes were condensed compared to the sham operation group, and this effect was inhibited by HW.

CONCLUSIONS: HW showed a protective effect against the progression of OA in an animal model, which may have been mediated by its anti-oxidant and anti-apoptotic activities.

Keywords: Chondrocytes, Osteoarthritis, ADAM Proteins, Aggrecans, Cartilage, Articular, Collagen Type II, Cyclooxygenase 2, Extracellular Matrix, Gene Expression Regulation, Hydrogen, Matrix Metalloproteinases, Nitric Oxide, Nitric Oxide Synthase Type II, Protective Agents, Water, bcl-2-Associated X Protein