Preliminary study on the mineral apposition rate in distal femoral epiphysis of New Zealand White Rabbit at skeletal maturity

Studies investigating the effect of different factors on the skeletal system require characterization of an appropriate animal model. Rabbits are among the most commonly studied animals for medical research, being used in about 35% of musculoskeletal research studies. The present dynamic cross-sectional histomorphometric study quantitatively determined mineral apposition rates (MARs) in the distal femoral epiphysis in four regions of interest (ROIs) in New Zealand white rabbits. ROIs included the craniolateral (CrL), caudolateral (CaL), craniomedial (CrM) and caudomedial (CaM) areas, using a reference height at different stages of skeletal maturity corresponding to experimental ages of 6, 7 and 8 months old (M6, M7 and M8). We evaluated whether a correlation exists in MARs between the times and the regions examined. Such data could be used in studies on growth of the rabbit’s femur, on biomaterials for bone integration or regeneration and on growth disturbances produced by various pathologic factors. We found no interaction at the experimental times; thus, M6, M7 and M8 are considered homogeneous in terms of MARs. The velocity profiles of the MARs were statistically significantly different among the considered ROIs. For all experimental times, the CrM region had a higher MAR than the other ROIs. Both the CrM and CaM ROIs had higher MARs than the corresponding lateral ROIs. Our results indicate that bone formation is not constant within the cross-section, but is statistically different between the ROIs considered.