OBJECTIVE Chondroitin sulfate (CS) is a glycosaminoglycan with proven anti-inflammatory, anti-apoptotic, anti-oxidant properties. CS increases type II collagen and proteoglycan synthesis in human joint chondrocytes. CS can reduce the production of pro-inflammatory mediators and proteases to improve the anabolic/catabolic balance of the extracellular cartilage matrix (ECM). Due to these characteristics, it is a natural compound that is considered to be Symptomatic Slow-Acting Drugs for Osteoarthritis (SYSADOA). Microbial chondroitin sulfate (MCS) was produced from two different bacterial sources using biotechnological methods by our team. In this study, we aimed to apply microbially produced CS and bovine-derived commercial CS forms to rabbit knees with osteoarthritis experimentally and to evaluate the results. METHODS In this study, a cruciate ligament cutting model was applied to 40 New Zealand rabbits to induce experimental osteoarthritis. Four weeks after the surgical procedure, rabbits were divided into 4 groups as control, animal-derived MCS, E coli-derived MCS and PaJC-derived MCS group. The standard rabbit diet was fed to the control group, and the other groups were additionally fed 17 mg/kg/day CS/MCS for 12 weeks. The rabbits were sacrificed at the 12th week after surgery and the preparations obtained were evaluated histopathologically. RESULTS As a result, it was observed that regeneration tissue was statistically significant in histopathological cartilage tissue compared to the control group of CS developed from different sources given to rabbits with osteoarthritis. It was determined that among the CS groups produced from different sources, the group with the highest chondroprotective effect was MCS originating from E.coli. CONCLUSIONS This vegan product (MCS), which we obtained as a result of our study, was produced by our team from a microbial source. According to our analysis, it has the potential to be an effective alternative therapy agent in the treatment of osteoarthritis.