高压氧对兔下颌骨牵引区骨保护素和整合素β1表达的影响

Effects of hyperbaric oxygen on the expression of osteoprotegerin and integrin β1 in rabbit's mandibular distraction gap

目的探讨高压氧(hyperbaric oxygen, HBO)对兔下颌骨牵引成骨过程骨保护素(osteoprotegerin, OPG)和整合素β1(integrin β1, ITGβ1)表达的影响。方法选取成年新西兰大白兔40只,建立兔下颌骨牵张成骨模型,分为实验组与对照组,每组20只。两组均于术后4 d以0.8 mm/d速度连续牵引10 d。实验组在牵引期开始每天给予高压氧处理连续4周,对照组仅作牵引。在牵引10 d、固定期7、14、28 d处死动物,行免疫组织化学染色检测OPG、ITGβ1在牵张区新生骨组织的表达,用图像分析软件行半定量分析。结果OPG主要定位于骨祖细胞、成骨细胞包膜和胞质,牵引结束后OPG表达呈上升趋势,至固定7 d时最高,随后逐渐下降。各时间点实验组OPG表达均高于对照组,差异有统计学意义(P<0.05)。ITGβ1主要定位于增殖分化活跃的成骨细胞、成纤维细胞、间充质细胞,以牵引10 d最强,随后逐渐下降。在牵引10 d和固定7 d、14 d时,实验组ITGβ1表达高于对照组,差异有统计学意义。固定28 d,ITGβ1表达明显减弱,组间差异无统计学意义(P>0.05)。结论HBO能促使牵引区组织中OPG、ITGβ1表达上调,促进成骨细胞分化、成熟,增强成骨细胞活性,从而促进牵引区新骨生成。

Objective To investigate the effect of hyperbaric-oxygen therapy on osteoprotegerin (OPG) and integrin β1 (Itgβ1) expression during mandibular distraction osteogenesis. Methods Forty New-Zealand rabbits were used. The animals were randomly divided into two groups (experimental group and control group) with 20 animals each;after accomplished osteotomy and implant distraction devices on mandible bilaterally for 3 days of latency period, the device was activated at the rate of 0.8 mm per day for 10 days. All animals in the experimental group were subjected to hyperbaric oxygen for 90 minutes once a day since the beginning of distraction, and lasted for four weeks. In control group, all the distractors were activated following the same distraction protocol as the experimental group, but without hyperbaric oxygen therapy. Five animals of each group were sacrificed at 10th day after distraction, 7th, 14th and 28th day of consolidation, respectively. The lengthened mandibles were harvested and processed for immunohistochemical examinations to detect OPG and Itgβ1 expression in the distraction gap. Semi-quantitative analysis was carried out by image analysis software. Results OPG staining was mainly located in the membrane and cytoplasm of osteoprogenitor cells and osteoblasts in the distraction zones. The expression of OPG increased after distraction accomplished and reached to the peak at 7th day of consolidation, and then decreased gradually. At every time point, the level of expression of OPG in the experimental group was remarkably higher than those in control group. There were significant differences between the experimental group and control group (P<0.01). Itgβ1 mainly located in actively proliferating osteoblasts, fibroblasts and mesenchymal cells. The expression of Itgβ1 decreased significantly after reached to the peak at the 10th day distraction. At 10th day distraction, 7th and 14th day of consolidation, Itgβ1 expressed more strongly than that in the experimental group, which was remarkably higher than those in control group. There were significant differences between experimental group and control group (P<0.05). At 28th day of consolidation, Itgβ1 expressed weakly;there was no significant difference between the two groups (P>0.05). Conclusions Hyperbaric oxygen therapy can up-regulate the expression of OPG and Itgβ1 in the distraction gap, which may promote osteoblast differentiation, proliferation, enhance osteoblast function, and new bone formation in distraction gap.