Objective The aim of this study was to evaluate the effects of a lyophilized inactivated culture (LIC) from Bifidobacterium longum CBi0703 in a spontaneous model of osteoarthritis (OA) in Dunkin Hartley guinea pigs. Histology of cartilage and synovial membrane was the primary outcome. Biomarkers were also considered to evaluate the treatment efficacy. Design LIC (1 µg/kg) with or without vitamin C (1 mg/kg) were tested in Dunkin Hartley guinea pigs spontaneously developing OA and compared with control (sterile water; CTL). Treatment was initiated orally in 16-week-old animals over a period of 12 weeks. Histological lesions of articular cartilage and synovial membrane were scored according to the OARSI (Osteoarthritis Research Society International) recommendations. Four biomarkers (Coll2-1, PIINAP, Fib3-2, and osteocalcin) were measured in animal sera. Results The global OARSI score increased with time in all group but no significant difference between groups was observed. When score items were analyzed individually, a significant lower score of cartilage structure was observed in the LIC + vitamin C group compared with CTL ( P < 0.0001). Synovial membrane showed a mild inflammatory reaction that was not affected by the treatment. LIC significantly decreased serum levels of Coll2-1 ( P = 0.0004 vs. CTL), a marker of type II collagen degradation and LIC + vitamin C significantly increased PIINAP ( P = 0.0003), a marker of type II collagen synthesis. The ratio Coll2-1/PIINAP was significantly decreased in both LIC groups ( P < 0.001). Conclusion Lyophilized inactivated culture of B. longum CBi0703 administrated orally over a period of 12 weeks decreased cartilage structure lesions and decreased type II collagen degradation suggesting a potential prophylactic effect on OA development.

Figure 1. Lactate dehydrogenase (LDH) release 24 h post-treatment with LU (treated) or no treatment (control). The result suggests that viability of chondrocytes was not affected by LU exposure.

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