The Effect of Chondroitin Sulfate with Different Molecular Weights on Monosodium Iodoacetate-Induced Osteoarthritis in Rats

Osteoarthritis is a prevalent chronic joint disease in humans, companion animals such as dogs and cats, and economic animals like horses and cattle. It primarily manifests as degeneration of articular cartilage, synovitis, and subchondral bone sclerosis, often leading to impaired mobility, reduced quality of life, and decreased production performance in affected animals. Chondroitin sulfate, a key component of the articular cartilage matrix, plays a role in alleviating and treating osteoarthritis. However, the molecular weight of chondroitin sulfate affects its permeability and bioavailability, exhibiting different effects on osteoarthritis. In this study, the monosodium iodoacetate-induced osteoarthritis model was established to evaluate the effects of three different-molecular-weight chondroitin sulfate on osteoarthritis through behavioral scoring, knee joint swelling degree, pain index, and knee joint histopathology, as well as the detection of inflammatory factors and COL2A1. Results demonstrated that all three types of chondroitin sulfate could alleviate joint swelling and pain, reduce the levels of IL-1β, IL-6, and TNF-α in cartilage tissue; inhibit the expression of MMP-13, MMP-3, and MMP-9; and promote the expression of COL2A1, SOX9 proteins, and Bcl-2/Bax proteins. Different-molecular-weight chondroitin sulfates showed significant ameliorating effects on the monosodium iodoacetate-induced osteoarthritis model, with protective efficacy increasing as the molecular weight decreased. The effect of low-molecular-weight chondroitin sulfate 2 was similar in magnitude to that of the positive drug.