Inhibition of cartilage degeneration and subchondral bone deterioration by Spinacia oleracea in human mimic of ACLT-induced osteoarthritis

Abstract

Osteoarthritis (OA) is an aging disorder characterized by degenerated cartilage and sub-chondral bone alteration in affected knee joints. Globally, millions of people suffer from this disease. However, there is a lack of safe and promising therapeutics, making the exploration and development of leads from natural sources urgent. Accordingly, food as medicine may be the most suitable approach for the treatment of this degenerative disease. Herein, we elucidated the protective role of Spinacia oleracea extract (SOE) in an anterior cruciate ligament transection (ACLT) model of osteoarthritis as a mimic of the human condition. ACL transection was done in the tibio-femoral joints of rats. SOE was orally administered at the dosage of 125 and 250 mg kg⁻¹ day⁻¹ for four weeks. It was shown that the animals with SOE treatment had better joint morphology than the ACLT animals, as evident by the shiny appearance of their cartilage. Hematoxylin and safranin-o staining showed that the number of chondrocytes was significantly reduced in the OA model, which was prevented with SOE treatment. The reduction in the cartilage thickness was well observed by toluidine blue staining. The reduced stain by safranin-o and toluidine blue, indicated proteoglycan loss in the ACLT-induced osteoarthritis model. The proteoglycan content and cartilage thickness were restored in the SOE group upon treatment at an SOE dosage of 125 and 250 mg kg⁻¹ day⁻¹. The micro-CT parameters of subchondral bone (SCB) and cartilage degradation markers in the serum corroborated our findings of the protective effects of SOE. In summary, our study suggests that SOE has therapeutic potential, which if taken regularly as a food supplement, can have beneficial effects.