Bone Marrow-derived Osteoblasts in the Management of Ovariectomy induced Osteoporosis in Rats.

Background: The objective of this study is to assess if infusion of osteoblasts can temporarily reverse osteoporosis in rats. Methods: Osteoporosis was induced in 20 female Sprague-Dawley rats by performing ovariectomy (OVX) that was carried out at 4 weeks of age. At 3 months a biopsy of the iliac crest was made to assess the bone quality and the same site bone marrow was harvested. From the bone marrow aspirate, MSCs were separated. Osteoblasts were then generated and were characterized using Alizarin red staining. Osteoblasts were injected in the tail vein of 10 rats. Two weeks after the injection of osteoblasts, a second biopsy was done. Animals were euthanized after 8 weeks of osteoblasts infusion by overdose of ketamine mixed with xylazine. The whole femurs and lumbar spine were dissected and the specimens were stored in 2% formalin. The specimens were analyzed using HRpQCT (High-resolution peripheral quantitative computerized tomography (μCT 100, SCANCO Medical AG, Brüttisellen, Switzerland). Results: In all the 10 animals from which bone aspiration was performed, osteoblasts were cultured and transplanted. Analysis showed that there was significant bone formation at bone sites of distal femur and lumbar spine (<0.001), with increased number of trabeculae and thickness (P<0.001). Further analysis revealed that there was robust bone formation in the animals that had osteoblasts injection. Conclusions: This preliminary study indicates that osteoblasts infusion can lead to new bone formation in osteoporosis induced by ovariectomy in rats.