The effect of age, anatomical site and bone structure on osteogenesis in New Zealand White rabbit

Among animal models, rabbits are widely used in medical research, as they fill the gap between smaller models, commonly employed in basic science, and larger ones, which are better suited for preclinical trials. Given their rapid growth, rabbits provide a valuable system for the evaluation of bone implants for tissue regeneration. By means of a histomorphometric analysis, here we quantified the mineral apposition rates (MARs) in osteonic, periosteum and endosteum osteogenic fronts, of skeletal elements within femur, tibia, radius, ulna, frontal and parietal bones in New Zealand White rabbits aged 6, 7 and 8 months. Our hypothesis is that the MAR varies according to the skeletal maturity of the animal, and also within the skeletal elements and the osteogenic fronts considered. In the present study we show that the MAR in both femur and tibia is significantly higher than in ulna and radius. We also demonstrate that the MAR in parietal bones is significantly higher compared to the MAR of both frontal and forelimb bones. Contrary to what was expected, the MARs of all the skeletal elements considered were not decreased following full skeletal maturity. Finally, the MAR of the osteonic-osteogenic front is the lowest in all of the skeletal elements considered. In conclusion, these results provide new important insights for the evaluation of bone implants, casting a light on the role of both age and osteogenic fronts on the bone MAR, and providing valuable information on the physiological bone turnover in New Zealand White rabbits.