Does dexmedetomidine induce bone regeneration in cranial defects in rabbits?

Dexmedetomidine has been shown to exert protective and curative effects on various tissues and organs in different pathological processes. This study aimed to investigate the effect of dexmedetomidine on the regeneration process after making holes in the parietal bones of rabbits. Twenty-four male Oryctolagus cuniculus rabbits were allocated to three groups, and an 8-mm circular parietal critical-sized bone defect was induced in each animal. Group_C (control) received saline; Group_LD (low dose) was given dexmedetomidine 2.75 µg/kg; Group_HD (high dose), dexmedetomidine 5.5 µg/kg; all were administered intraperitoneally for 7 days. After 8 weeks the bones were examined by micro-computed tomography (micro-CT) and histomorphometry. The results indicated that regeneration was improved in both the dexmedetomidine-treated groups. The lower dose increased the bone volume ratio (BV/TV) more than the higher dose. Trabecular thickness, connectivity value, and connectivity density were also higher in Group_LD than in Group_HD. Significant intramembranous ossification was observed in the dexmedetomidine-treated groups, and active osteoblasts were seen at the margins of new bone trabeculae. We conclude that dexmedetomidine, especially at the lower dosage, increases osteoblastic activity and regeneration quality.