Hydrolyzed collagen contributes to osteoblast differentiation in vitro and subsequent bone health in vivo

Purpose: Collagen I is the main component of organic bone matrix. Its correct synthesis folding and degradation are crucial for bone homeostasis. According to this pivotal role in bone structure we investigated the potential health benefits of hydrolyzed collagen (HC) on bone using translational approaches. Methods & Results: Regarding the influence of HC on bone forming cells in vitro we first insured the absence of cytotoxicity of HC addition in culture media. Consistently as compared to BSA control conditions HC even promoted pre-osteoblast proliferation. Then cells were tested for differentiation parameters in the presence of HC. HC from bovine origin resulted in a significantly higher alkaline phosphatase activity after 7 days of incubation when compared to its BSA control condition. This observation was supported by mineralization assays demonstrating that bovine HC enhanced Ca/P nodule formation in MC3T3-E1 cultures. To confirm these encouraging results C3H/HeN mice were ovariectomized (OVX) to induce bone loss and were given in parallel HC enriched diets to determine whether HC intake may contribute to bone health by preventing decrease in bone mineral density upon OVX. Diets were designed to contain 15% casein 17.5% casein or 15% casein plus 2.5% HC from bovine origin. Conclusion: As expected OVX induced a dramatic loss of bone mineral density. However HC fed OVX mice exhibited a significant higher BMD than OVX control mice suggesting a nutritional protective effect of HC confirming previous results and further supporting its potential benefits on bone health.