Adipose Derived Stem Cell on the Regeneration of Irradiated Mandible of Adult Rabbit Submitted to Distraction Osteogenesis

Purpose: To evaluate the effect of adipose derived mesenchymal stem cell (ADSC) on the regeneration of irradiated mandible submitted to distraction osteogenesis on adult rabbits. Methods: Ten adult rabbits were selected and the dorsal fat was harvested for isolation, dissociation and culture of adipose derived adult mesenchymal stem cells. The mandibles were irradiated on a single dose of 20 Gy. After 30 days the animals underwent mandibular lengthening by distraction osteogenesis. After 10 mm of lengthening, the animals were distributed into two groups. Saline solution (1 mL) was injected the control group, and supplemented with ADSC, on the study group. After 4 weeks the mandibles were removed and evaluated by tomography and histomorphometric analysis. Histomorphometric was obtained and statistical analysis done by Mann-Withney test (p > 0.05). Results: The tomography shows a significant improvement on the Hounsfield scale for lateral fibrovascular zone (114.5 ± 9.7 control group to 148 ± 24, p = 0.0045) and central fibrovascular zone (37 ± 13.4 control group to 96 ± 41.8 on study group p = 0.0045). The Histomorphometric analysis demonstrated an increase area of new bone formation. The mineralized area was of 61.2 ± 9.9% in the study group and 31.3 ± 10.6% in the control group (p = 0.0045) for the central fibrovascular zone, 79.1 ± 9.1% in the study group and 39.1 ± 14.7 on control group for anterior fibrovascular zone (p = 0.0001) and 67.7 ± 12.9% in the study group and 38.4 ÷ 12.9% in control group for posterior fibrovascular zone (p = 0.0001). Conclusions: The injection of adipose derived mesenchymal stem cell was effective to improve bone regeneration distraction callus on the irradiated mandible.