摘要目的 观察高压氧治疗海水浸泡兔胫骨开放性骨折的效果及其作用机制.方法 取新西兰兔48只,按数字表法随机分为高压氧组和对照组,每组24只.2组均造成单侧胫骨开放性骨折,伤肢浸泡于人工海水中3h,清创后固定骨折并缝合伤口.高压氧组术后立即行高压氧治疗,每天1次,连续2周,对照组组术后未行高压氧治疗.于伤后第4、8、12周分批处死后取材(每组8只肢体).通过影像学分析、组织学及免疫组织化学观察,比较各组骨折区修复情况.结果 (1)组织学观察,进行HE染色,伤后第12周时,高压氧组骨折区基本为骨性骨痂,细胞成分多为成熟骨细胞,未观察到明显炎性细胞浸润,对照组骨折区大部分为混合骨痂,其中仍可见软骨细胞,并可见少量炎症细胞浸润.(2)免疫组织化学观察,骨痂中,血管内皮生长因子(VEGF)主要表达在成骨细胞、软骨细胞及骨细胞胞浆内,在不同时相点有明显的变化.伤后第4周,2组的表达水平均为最高;至第8周及第12周,其表达均逐渐回落至低水平.伤后第4、8周,高压氧组的表达水平强于对照组(P＜0.01).而伤后第12周时,2组间比较已无明显差异.(3)影像学观察,骨折区骨痂灰度值测量,伤后第12周时,高压氧组骨折区骨痂平均灰度值为190.58±7.52,对照组为144.00±8.11,组间差异具有统计学意义(P＜0.01).(4)在伤后第4周时,高压氧组骨折周围软组织丙二醛(MDA)含量明显低于对照组、超氧化物歧化酶(SOD)活性高于对照组,差异有统计学意义(均P＜0.01);而在第8周和第12周时,2组MDA含量及SOD活性无明显差异.结论 高压氧治疗海水浸泡兔胫骨开放性骨折可减轻受损组织的炎症反应及再灌注损伤,促进组织细胞增殖,有利于骨折愈合,是修复海水浸泡开放性骨折的可行方法.

abstractsObjective To investigate the effects of HBO on open tibial fracture coupled with seawater immersion in rabbits and the possible mechanism involved.Methods Forty-eight New Zealand rabbits were selected and randomly divided into the HBO group and the control group,each consisting of 24 animals.The animals of both groups were inflicted with unilateral open tibial fracture.The injured limbs were immersed in artificial seawater for 3 hours,and then had wound suture and internal fracture fixation after debridement.The animals in the HBO group was immediately treated with HBO,once a day for a succession of 2 weeks,whereas the animals in the Control group were left there untreated.At week 4,8 and 12 after injury,the animals were sacrificed and samples (8 limbs from each group) were collected for further study.The repair of the fractured tissues of both groups was compared by radiography,histology and immunohistochemistry.Results (1)Histopathology was performed by HE staining.At week 12 after injury,for the animals in the HBO group,osseous callus could universally be seen in the fracture zone,cell components were basically mature bone cells,and the infiltration of inflammatory cells could scarcely be seen,while for the animals in the Control group,mixed bone callus could mainly be noted in the fracture zone,but cartilage cells were still visible,and a small scale of inflammatory cell infiltration could also be observed.(2) Immunohistochemistry revealed that vascular endothelial growth factor (VEGF) was mainly expressed in the cytoplasm of osteoblast,chondrocytes and osteocyte,and significant changes could be seen at different time points.At week 4 after injury,the expression levels of the two groups were the highest.At week 8 and 12 after injury,the expression levels all gradually dropped to a relatively low level.At week 4 and 8 after injury,the expression level of the HBO group was obviously stronger than that of the Control group(P ＜0.01).However,at week 12 after injury,no significant differences could be noted in the expression levels between the 2 groups (P ＞ 0.05).(3) Radiographic imaging was performed for the detection of callus grayscale in the fracture zone.At week 12 after injury,the average value of callus grayscale in the fracture zone for the animals of the HBO group was (190.58 ± 7.52),while that of the Control group was (144 ± 8.11).Statistically significance was shown,when comparisons were made between the 2 groups (P ＜0.01).(4)At week 4 after injury,the content of malondialdehyde (MDA) in the soft tissue around the fracture zone in the animals of the HBO group was significantly lower than that of the Control group,and the activity of superoxide dismutase (SOD) in the animals of the HBO group was higher than that of the Control group.Statistical significance could be seen,when comparisons were made between the 2 groups (P ＜ 0.01).However,at week 8 and 12 after injury,there were no significant differences in the content of MDA and activity of SOD between the 2 groups (P ＞ 0.05).Conclusions In the treatment of open bone fracture coupled with seawater immersion,HBO could alleviate inflammatory reaction and reperfusion injury,enhance the proliferation of tissue cells,and was beneficial to the healing of bone fracture.For this reason,this regimen was a practical method for the repair of open bone fracture coupled with seawater immersion.