夹竹桃麻素对快速起搏离体兔心脏氧化应激损伤的保护作用

目的研究还原性烟酰胺腺嘌呤二核苷酸磷酸（NADPH）氧化酶抑制剂夹竹桃麻素（APO）对快速起搏离体兔心脏氧化应激损伤的保护作用。方法采用离体兔心脏Langendorff灌注装置建立快速起掉右心房实验模型，离体兔心脏24只随机分成正常对照组、快速起搏组（RAP）和夹竹桃麻素预处理组（APO），每组8只。正常对照组用K—H液灌注离体兔心脏80min；RAP组离体灌流30min，电极快速起搏右心房50min；APO纰用夹竹桃麻素预处理30min，快速起搏50min。所有组灌流结束后，留取心房肌组织。H—E染色检测心房肌病理变化，免疫组化和Westernblot检测心房肌组织中蛋白表达并测定超氧化物歧化酶（SOD）、丙二醛（MDA）的变化。结果①正常对照组心肌细胞排列整齐，结构正常；RAP组心肌细胞排列紊乱，大量心肌细胞溶解；APO组心肌细胞排列较RAP组整齐，可见部分心肌细胞溶解；②与正常对照组比，RAP组心房肌钙激活蛋白酶calpainl表达增加（P〈0．05），SOD蛋白和肌钙蛋白T（cTnT）表达减少（P〈0．05）；与RAP组比，APO组心房肌calpainl蛋白表达减少（P〈0．05），SOD蛋白和cTnT蛋白表达均增加（P〈0．05）；③与正常组比，RAP组心房肌MDA水平明显增加（P〈0．05），SOD水平明显减少（P〈0．05）；与RAP组比，APO组心房肌MDA水平减少（P〈0．05），SOD水平增加（P〈0．05）。结论夹竹桃麻素可以通过抑制氧化应激，减轻快速起搏离体兔心房导致的心肌氧化应激损伤。

Protective effect of apocynin against oxidative stress injury induced by rapid-pacing in isolated rabbit hearts

Objective To investigate the protective effect of apocynin（ APO）, a NADPH oxidase inhibitor, on oxida- tive stress injury induced by rapid -pacing in isolated rabbit hearts. Methods The experiment was performed on isola- ted rabbit hearts perfused on Langendorff apparatus. 24 rabbit hearts were randomized into 3 - groups： control group, rapid atrial pacing group （RAP）, apocynin pretreatment （APO）, with 8 rabbit hearts in each group. The control group was perfused with Krebs -Henseleit buffer （K- H） solution at 4℃ for 80 min, The RAP group was firstly perfused with K - H solution for 30 min and then rapid pacing on the right atrium of the isolated rabbit hearts for 50 min, The APO group was firstly pretreated with apocynin for 30 min and then rapid pacing on the right atrium of the isolated rabbit hearts for 50 min. At the end of all the groups repeffused, the atrial tissue was obtained and stored for further study. HE staining was used to observe the pathological change. The immunohistochemical and Western blot were used to detect the expres- sion of the proteins. The activities of superoxide dismutase （SOD） and maleic dialdehyde （MDA） in tissue homogenate from RA were measured. Results ① HE staining： Atrial myocytes with the normal structure of the normal group ar- ranged in neat rows, In the RAP group,a large number of atrial myocytes were dissolved and arranged in disorder. The APO group was similar to the control group. ② The expression of the proteins ： Compared with the control group, the ex- pression of calpainl was significantly increased in RAP group, but the expressions of SOD, cTnT were significantly lower in RAP. Compared with RAP group, the expression of calpainl was significantly lower in the APO group, but the expres-sions of SOD, cTnT were significantly increased （P 〈 0.05）. ③ Compared with control group, the activity of SOD was reduced （P 〈 0.05）, but the activity of MDA was elevated in RAP group （P 〈 0.05）. Compared with RAP group, the activity of SOD was elevated, but the activity of MDA was decreased in APO group （P 〈 0.05 ）. Conclusion Apocynin, the inhibitor of oxidative stress, could relieve the oxidative stress injury induced by rapid - pacing the isolated rabbit hearts.