Chondroprotection of fruit peels in a monosodium iodoacetate‐induced osteoarthritis rat model via downregulation of Col1A1

Abstract

The potential of the fruit peels of mango, orange, cantaloupe, and pomegranate in the treatment of osteoarthritis (OA) was evaluated in a rat model. Their metabolic profiles were characterized using ultrahigh‐performance liquid chromatography (UPLC)–electrospray ionization‐mass spectroscopy and 66 albino rats were intra‐ articularly injected with monosodium iodoacetate in the knee joints. The extracts were orally administered at doses of 200 and 400 mg/kg for 28 days. Serum levels of IL‐6 and tissue levels of cyclooxygenase‐2 (COX‐2), peroxisome proliferator‐ activated receptor‐gamma (PPARγ), and alpha‐smooth muscle actin (α‐SMA) were measured using ELISA. COL1A1 expression was measured by quantitative polymerase chain reaction. Histopathological changes in the joints were examined. In the extracts, 85 metabolites were annotated, and the levels of interleukin (IL)‐6, COX‐2, α‐SMA, malondialdehyde, and nitric oxide were significantly reduced, while PPARγ and glutathione levels were significantly raised in all treated groups compared to the OA group. All extracts downregulated the cartilage mRNA expressions for COL1A1 dose‐dependently. Mango peel extract exhibited the best chondroprotective effect. The in silico study showed the link between mango extract metabolites and COX‐2.