Heat-Treated Lacticaseibacillus rhamnosus Strains Modulate Inflammatory and Metabolic Processes in In Vitro Systems Relevant to Canine Osteoarthritis

Canine osteoarthritis is a progressive degenerative joint condition characterized by inflammation, structural damage, pain, and impaired joint function. Osteoarthritis risk is influenced not only by well-established factors such as age, genetics, obesity and underlying arthropathies, but also by systemic conditions such as low-grade inflammation and sarcopenia. Current interventions are primarily focused on pain relief rather than mitigating physiological impairment, despite recent veterinary guidelines. In this study, several preclinical models were employed to identify postbiotic candidates with potential to promote canine joint health. An initial screening of nine heat-treated bacterial strains identified two <i>Lacticaseibacillus rhamnosus</i> strains, PRIOME^® JH and HT-PB01, which demonstrated significant anti-inflammatory activity on canine chondrocytes. Further characterization revealed that these two strains significantly increased type II collagen synthesis in canine chondrocytes and modulate immune responses in canine macrophages, enhancing Interleukin-10 secretion over Interleukin-12. Additionally, both strains showed potential in mitigating risk factors such as gut inflammation and permeability, fat accumulation and sarcopenia in <i>Caenorhabditis elegans</i> models. In conclusion, this study identified two promising postbiotic candidates, PRIOME^® JH and HT-PB01, with the potential to target key risk factors associated with osteoarthritis through multifactorial mechanisms. These findings emphasize conducting dog clinical trials to evaluate their relevance in osteoarthritis.