高压氧治疗对兔下颌骨牵引区新生骨骨密度及生物力学的影响

Effect of hyperbaric oxygen therapy on bone mineral density and biomechanics of new-formed bone in mandibular distraction gap in rabbits

目的探讨高压氧治疗对兔下颌骨牵引区新生骨骨密度和生物力学的影响。方法选取日本大耳白兔30只，双侧下颌骨截骨植入牵引器后随机分成高压氧治疗（HBOT）组和非HBOT组。均经过5d潜伏期后，以0．8mm／d速度连续牵引10d，停止牵引进入固定期。HBOT组在术后给予HBOT直至牵引结束，非HBOT组不行高压氧治疗。分别于固定期7，14，28d处死动物，取材检测牵引区新骨生成情况、骨密度和生物力学指标。结果在固定7d时骨密度两组差异无统计学意义（P〉0．05），其余各时点HBOT组新生骨组织的骨密度值高于非HBOT组（P〈0．05）。固定28d时两组新生骨的骨强度、弹性模量及最大破坏能量差异均有统计学意义（P〈0．05）。结论HBOT能够提高下颌骨牵引间隙新生骨的骨密度与骨强度。

Objective To observe the effect of hyperbaric oxygen therapy （HBOT） on mineral density and biomechanics of new-formed bone in distraction gap. Methods The mandibles were subjected to osteotomy and distractors were placed bilaterly in 30 rabbits, which were divided randomly into 2 groups. After 5 days for latency, the mandibles were distracted at a rate of 0.8 mm/day for 10 days, and then for consolidation. After surgery, group A received HBOT with daily distraction, whereas group B only distracted without HBOT served as control group. The animals in groups A and B were sacrificed 1 wk, 2 wk, 4 wk of consolidation, respectively. The mandibles were harvested and subjected to examination for new bone formation, and bone mineral density （BMD） and biomechanics of newly formed bone in the distraction gap. Results At one week of consolidation, no significant differences were observed between the BMD of newly formed bone in the two groups （P〈0.05）, however, at the other time points, BMD of newly formed bone in group A was significantly higher than that in group B （P〈0.05）. Moreover, at 4 weeks of consolidation, the strength, maximum fragile energy and modulus of elasticity of newly formed bone in group A were significantly higher than those in group B （P〈0.05）. Conclusions The results suggest that HBOT improves mineral density and strength of new-formed bone in distraction gap.