目的 探讨不同频次的高压氧预处理对大鼠皮瓣移植术后存活率及缺血再灌注损伤的影响,初步探索提高移植术后皮瓣存活率的最佳预处理条件.方法 将36只SD大鼠按照随机数字表法分为4组,每组9只.分别于术前对4组大鼠予以高压氧预处理0、2、4、6d,即对照组、预处理2d组、预处理4d组、预处理6d组.以大鼠背部正中线为轴,设计切取1个蒂在尾端且距髂后上棘约1 cm的超长随意皮瓣,大小为10.0 cm×2.5 cm.大体观察各组术后皮瓣成活情况,并测定术后第7天皮瓣最终的存活面积及存活率.术后第7天在距皮瓣蒂部5 cm处进行组织取材,行组织病理学观察;采用免疫组织化学法检测皮瓣组织中超氧化物歧化酶(SOD)及丙二醛(MDA)含量水平,计算各组阳性细胞表达率;以免疫荧光技术检测白细胞介素-6(IL-6)在皮瓣组织中的表达情况.采用方差分析对各组测量值进行比较,以P<0.05为差异有统计学意义.结果 术后第7天,各高压氧预处理组的大鼠移植皮瓣存活面积和存活率均明显高于对照组(P<0.05),且预处理4d组及6d组明显高于预处理2d组(P<0.05),但预处理4d组与6d组间差异无统计学意义(P=0.095).术后第7天病理学观察,对照组出现部分坏死灶,预处理2d组炎症细胞较多血管结构较少,预处理4d组可见较多新生血管,预处理6d组炎症细胞最少,新生血管情况同预处理4d组.对照组SOD的吸光度A值为0.009 7±0.000 3,其阳性表达率为20%,显著低于各高压氧预处理组,差异具有统计学意义(P<0.05).而对照组MDA的吸光度A值为0.055 1±0.003 0,其阳性表达率为55%,显著高于各高压氧预处理组,差异具有统计学意义(P<0.05).其中,预处理2d组的SOD吸光度A值为0.023 8±0.003 0,阳性表达率为30%,低于预处理4d组(吸光度A值0.046 9±0.003 0,阳性表达率35%)和6 d组(吸光度A值0.047 2±0.003 6,阳性表达率40%),而预处理2d组的MDA吸光度A值为0.037 2±0.003 2,阳性表达率30%,均高于预处理4d组(吸光度A值0.014 7±.0.002 4,阳性表达率5%)和6d组(吸光度A值0.017 0±0.001 8,阳性表达率10%),差异均具有统计学意义(P<0.05).但预处理4d组与预处理6d组相比,SOD及MDA的表达差异均无统计学意义(P>0.05).IL-6在各高压氧预处理组中的表达均显著低于对照组(吸光度A值44.937 0±0.594 0),差异具有统计学意义(P<0.05),其中预处理2d组中的吸光度A值为41.698 0±0.724 0,明显高于预处理4d组(吸光度A值34.049 0±0.323 0)及6d组(吸光度A值33.524 0±0.639 0),差异具有统计学意义(P<0.05),但预处理4d组的表达与6d组相比,差异无统计学意义(P=0.068).结论 高压氧预处理能明显促进大鼠皮瓣移植术后的存活,且术前每日1次,连续4d的高压氧预处理,更能增强皮瓣组织对缺血缺氧的耐受,减轻组织的缺血再灌注损伤.
Objective To explore the effect of hyperbaric oxygen preconditioning with different frequency on the survival rate of flap and ischemia-reperfusion injury in rats after transplantation,and to explore the best preconditioning conditions to improve the survival rate of rat flaps after transplantation.Methods Thirty-six Sprague Dawley rats were randomly divided into four groups according to the random number table method,9 groups in each group.Four groups of rats were pretreated with hyperbaric oxygen pretreatment for 0,2,4,and 6 days before the operation,control group,pretreatment 2 d group,pretreatment 4 d group,and pretreatment 6 d group.Taking the midline of the back of the rat as the axis,an ultra-long random flap with a pedicle at the tail end and about 1 cm from the superior iliac spine was designed and cut to a size of 10.0 cm×2.5 cm.The survival of the flaps in each group was observed and the final survival area and survival rate of the flaps were measured on the 7th day after surgery.On the 7th day after operation,the tissue was taken at a distance of 5 cm from the pedicle,and the histopathology was observed;The content of superoxide dismutase (SOD) and malondialdehyde (MDA) in flap tissue was detected by immunohistochemistry,and the expression rate of positive cells in each group was calculated.Immunofluorescence was used to detect the expression of interleukin-6 (IL-6) in the flap tissue.Results On the 7th day after the operation,the survival area and survival rate of the transplanted flaps in the hyperbaric oxygen pretreatment group were significantly higher than those in the control group (P<0.05),and the pretreatment 4 d and 6 d groups were significantly higher than the pretreated 2 d group (P<0.05),but there was no significant difference between the pretreated 4 d group and the 6 d group (P =0.095).Pathological observation on the 7th day after operation showed that there was some necrosis in the control group,the vascular cells in the pretreated 2 d group had more vascular structures,and more neovascularization was observed in the pretreated 4 d group.The inflammatory cells were the least in the 6 d pretreatment group,and the neovascularization was the same as the pretreatment 4 d group.The absorbance A value of SOD in the control group was 0.009 7±0.000 3,and the positive expression rate was 20%,which was significantly lower than that in the hyperbaric oxygen pretreatment group.The difference was statistically significant (P<0.05).However,the absorbance A value of MDA in the control group was 0.055 1±0.003 0,and the positive expression rate was 55%,which was significantly higher than that in the hyperbaric oxygen pretreatment group.The difference was statistically significant (P<0.05).Among them,the SOD absorbance A value of the pretreated 2 d group was 0.023 8±0.003 0,and the positive expression rate was 30%,which was lower than the pretreatment 4 d group (absorbance A value 0.046 9±0.003 0,positive expression rate 35%) and 6 d group (absorbance A value 0.047 2±0.003 6,positive expression rate 40%),The MDA absorbance A value of the pretreated 2 d group was 0.037 2±0.003 2,and the positive expression rate was 30%,which was higher than the pretreatment 4 d group (absorbance A value 0.014 7±0.002 4,positive expression rate 5%) and 6 d group (absorbance A value 0.017 0±0.001 8,positive expression rate 10%),the difference was statistically significant (P<0.05).However,there was no significant difference in the expression of SOD and MDA between the pretreated 4 d group and the pretreated 6 d group (P>0.05).The expression of IL-6 in the hyperbaric oxygen pretreatment group was significantly lower than that in the control group (absorbance A value 44.937 0±0.594 0),the difference was statistically significant (P<0.05).The absorbance A value in the pretreated 2 d group was 41.698 0±0.724 0,which was significantly higher than the pretreatment 4 d group (absorbance A value 34.049 0±0.323 0) and 6 d group (absorbance A value 33.524 0±0.639 0).The difference was statistically significant (P<0.05).There was no significant difference in the expression of the pretreated 4 d group compared with the 6 d group (P =0.068).Conclusions Hyperbaric oxygen preconditioning can significantly promote the survival of rat flaps after transplantation.Preoperative hyperbaric oxygen preconditioning once daily for 4 consecutive days,can enhance the tolerance of flap tissue to ischemia and anoxia and reduce tissue ischemia-reperfusion injury.