Does the intraperitoneal dexmedetomidine induce bone regeneration in
cranial defects at subsedative doses in rabbits?
Abstract
Objective: 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 inducing a
critical-sized bone defect in the calvarium of rabbits. Subject
and Methods: Twenty-four male Oryctolagus cuniculus rabbits were
divided into three groups, and an 8-mm circular parietal critical-sized
bone defect was induced in all groups. Group_LD was given
dexmedetomidine 2.75 µg/kg; Group_HD, dexmedetomidine 5.5 µg/kg; and
Group_C, saline; all administered intraperitoneally for 7 days. The
blood pressure and sedation score of the rabbits were evaluated. Bone
tissue samples collected at the end of 8 weeks were examined via
micro-computed tomography (micro-CT) and histomorphometry.
Results: The micro-CT results indicated that regeneration
significantly improved in all parameters in the dexmedetomidine-treated
groups (p < 0.001). Furthermore, low-dose dexmedetomidine
statistically significantly increased the bone volume ratio (BV/TV)
compared with high-dose dexmedetomidine (p = 0.002). Trabecular
thickness, connectivity value, and connectivity density were
statistically significantly higher in Group_LD than in Group_HD (p
< 0.001). The highest BA/TA% measurement in histomorphometry
was observed in Group_HD, with a mean of 29.81% ± 8.52%. Significant
intramembranous ossification was observed in the dexmedetomidine-treated
groups, and active osteoblasts were observed in at the margin of the new
bone trabeculae. Conclusion: This study demonstrated that
dexmedetomidine increases osteoblastic activity and regeneration
quality. In particular, low-dose dexmedetomidine exerted a more
significant positive effect on the regeneration process and regenerative
tissue quality than high-dose dexmedetomidine according to the micro-CT
parameters.