Askar Ibrahim, Bozkurt Mehmet
Department of Plastic and Reconstructive Surgery, Dicle University Medical School, Diyarbakir, Turkey.
Microsurgery. 2002;22(8):361-6. doi: 10.1002/micr.10071.
The sequential events between leukocytes and endothelium have significant implications in surgical procedures, trauma, vascular injury, and wound healing. These sequential events are mediated by free oxygen radicals, leukocytes, red blood cells, and endothelial cells. In this study, we investigated the protective effects of steroids and immunosuppressants against ischemia-reperfusion injury in cremaster muscle flaps at the microcirculatory level. In this experimental study, 50 male Sprague-Dawley rats, weighing about 120-130 g, were used. The rats were divided into five groups of 10 rats each: the control group (group 1, n = 10), methyl prednisolone group (group 2, n = 10), dexamethasone group (group 3, n = 10), cyclosporin A group (group 4, n = 10), and azathioprine (group 5, n = 10). Surgical procedures were divided into two stages. In the first stage, a cremaster muscle end-organ tube flap was created by extracting the testes and spermatic cord. The flap was placed into a subcutaneous tunnel in the anteromedial aspect of the ipsilateral limb. In the experimental groups, ischemia was performed by clamping the femoral artery and vein above and below the cremaster pedicle for 4 h. Then the clamps were removed, and perfusion of the cremaster muscle was allowed for 24 h. In the second stage, a round flap was obtained from the cremaster muscle tube-flap to evaluate microcirculation after 24 h of reperfusion, and dissected along its front wall using cauterization. Vessel diameter, red blood cell velocities, leukocyte activation, perfused capillaries, and endothelial edema index were measured and evaluated statistically. There was a significant decrease in the number of rolling, sticking, and transmigrating neutrophils of groups 2 (cyclosporin A), 4 (methylprednisolone), and 3 (azathioprine) (P < 0.05), whereas those of group 5 (dexamethasone) were not decreased (P > 0.05). There was a significant increase in the number of perfused capillaries of groups 2 (cyclosporin A), 4 (methylprednisolone), and 3 (azathioprine) (P < 0.05), nearly 0.75-, 0.5-, and 0.75-fold, respectively. We conclude that cyclosporin and azathioprine showed a protective effect on muscle tissue against ischemia-reperfusion injury by inhibiting leukocyte infiltration, and that methylprednisolone had a beneficial effect against ischemia-reperfusion injury by reducing the synthesis of eicosanoids, edema formation, and leukocyte infiltration. However, we believe that dexamethasone might have a salutary effect due to reducing the synthesis of eicosanoids, edema formation, and release of free oxygen radicals, but not due to leukocyte infiltration.
白细胞与内皮细胞之间的一系列连续事件在外科手术、创伤、血管损伤和伤口愈合中具有重要意义。这些连续事件由游离氧自由基、白细胞、红细胞和内皮细胞介导。在本研究中，我们在微循环水平研究了类固醇和免疫抑制剂对提睾肌皮瓣缺血再灌注损伤的保护作用。在这项实验研究中，使用了50只体重约120 - 130克的雄性Sprague-Dawley大鼠。大鼠被分为五组，每组10只：对照组（第1组，n = 10）、甲基泼尼松龙组（第2组，n = 10）、地塞米松组（第3组，n = 10）、环孢素A组（第4组，n = 10）和硫唑嘌呤组（第5组，n = 10）。手术过程分为两个阶段。在第一阶段，通过提取睾丸和精索创建一个提睾肌终末器官管状皮瓣。将皮瓣置于同侧肢体前内侧的皮下隧道中。在实验组中，通过夹闭提睾肌蒂上方和下方的股动脉和静脉4小时来造成缺血。然后移除夹子，使提睾肌灌注24小时。在第二阶段，从提睾肌管状皮瓣获取一个圆形皮瓣，以评估再灌注24小时后的微循环，并使用烧灼法沿其前壁进行解剖。测量血管直径、红细胞速度、白细胞活化、灌注毛细血管和内皮水肿指数，并进行统计学评估。第2组（环孢素A）、第4组（甲基泼尼松龙）和第3组（硫唑嘌呤）的滚动、黏附和迁移中性粒细胞数量显著减少（P < 0.05），而第5组（地塞米松）的中性粒细胞数量未减少（P > 0.05）。第2组（环孢素A）、第4组（甲基泼尼松龙）和第3组（硫唑嘌呤）的灌注毛细血管数量显著增加（P < 0.05），分别增加了近0.75倍、0.5倍和0.75倍。我们得出结论，环孢素和硫唑嘌呤通过抑制白细胞浸润对肌肉组织缺血再灌注损伤具有保护作用，甲基泼尼松龙通过减少类花生酸合成、水肿形成和白细胞浸润对缺血再灌注损伤具有有益作用。然而，我们认为地塞米松可能由于减少类花生酸合成、水肿形成和游离氧自由基释放而具有有益作用，但不是由于白细胞浸润。
