Metformin and Resveratrol Suppress Type 2 Diabetes Mellitus-Induced Articular Cartilage Damage in Rats Associated with the Inhibition of Inflammation and Augmentation of Proteoglycans

Abstract

Induction of osteoarthritis (OA) following diabetes is characterized by a sever inflammation of the joints that can lead to disability. The cartilage content of proteoglycans can substantially be reduced, following the induction of diabetes mellitus associated with inflammation as well as knee joint injury, and the antidiabetic drug metformin combined with the anti-inflammatory agent resveratrol can prevent these deleterious effects. Therefore, insulin-independent diabetes, type 2 diabetes mellitus (T2DM) was induced in Albino rats by streptozotocin (STZ) injection (50 mg/kg) after being fed on a high carbohydrate and fat diets for 2 weeks. The protective group of rats which also received a single injection of STZ was treated daily with metformin (Met; 200 mg/kg) and resveratrol (Res; 30 mg/kg) for 12 weeks. Harvested knee joint tissues were prepared for basic histology stain and for proteoglycans staining using light microscopy. Histology images showed in diabetic rats (T2DM) OA development as demonstrated by profound injury to the knee joint and severe decrease of articular cartilage proteoglycans content, which were substantialy protected by Met+Res. Met+Res also significantly (p< 0.0001) decreased diabetes induced glycemia, dyslipidemia, and the inflammatory biomarkers, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and high sensitivity C-reactive protein (hs-CRP). In addition, there was a significant correlation between OA and glycemia, dyslipidemia, and inflammation. Collectively, we demonstrate an association between knee joint damage and biomarkers of glycemia, dyslipidemia, and inflammation in diabetes-induced OA, with metformin plus resveratrol providing protective effects.