Histological and Histomorphometric Analyses of Bone Regeneration in Osteoporotic Rats Using a Xenograft Material

We evaluated the effect of osteoporotic induction after eight weeks of initial healing of bone defects grafted with a xenograft material in a rat model. Bone defects were created in the femoral condyles of 16 female Wistar rats (one defect per rat). The defects were filled with bovine bone (Inter-Oss) granules. After eight weeks of bone healing, rats were randomly ovariectomized (OVX) or sham-operated (SHAM). At 14 weeks of bone healing, all animals were euthanized. Bone specimens were harvested and processed for histological and histomorphometric analyses to assess new bone formation (N-BF%), remaining bone graft (RBG%) and trabecular bone space (Tb.Sp%) within the defect area. After 14 weeks of bone healing, histological evaluation revealed a significant alteration in trabecular bone in OVX rats compared to SHAM rats. There was lower N-BF% in OVX rats (22.5% +/- 3.0%) compared to SHAM rats (37.7% +/- 7.9%; p < 0.05). Additionally, the RBG% was significantly lower in OVX (23.7% +/- 5.8%) compared to SHAM (34.8% +/- 9.6%; p < 0.05) rats. Finally, the Tb.Sp% was higher in OVX (53.8% +/- 7.7%) compared to SHAM (27.5% +/- 14.3%; p < 0.05) rats. In conclusion, within the limitations of this study, inducing an osteoporotic condition in a rat model negatively influenced bone regeneration in the created bone defect and grafted with a xenograft material.

Automated summary

Inducing osteoporotic conditions in rat models negatively affected bone defect healing and xenograft material grafting, leading to reduced new bone formation, decreased remaining bone graft, and increased trabecular bone space.