岛状皮瓣缺血-再灌注损伤后组织结构的变化及地塞米松的保护性作用

Histopathological changes of island skin flaps and the modulation of dexamethasone

目的:研究岛状皮瓣缺血-再灌注损伤后组织学,阐明中性粒细胞在这一过程中的作用及地塞米松的保护作用。方法:wistar大鼠等分为地塞米松治疗组与生理盐水对照组。观察组织学改变。结果:治疗组皮瓣成活面积明显增加。光镜显示:皮瓣组织学改变轻。透射电镜发现中性粒细胞坏死数量较小,凋亡数量较多,皮瓣毛细血管结构较完整。扫描电镜显示:血管通畅,中性粒细胞活化程度轻,与血管壁粘附现象少见。对照组皮瓣组织学改变重;光镜显示:术后1天即可见皮瓣内血管有大量血栓形成,皮瓣中性粒细胞浸润数量多;透射电镜显示皮瓣毛细血管结构不完整,内皮细胞坏死,脱落,皮瓣中有较多数量的坏死中性粒细胞,少见凋亡的中性粒细胞,3天时中性粒细胞数量明显减少,但皮瓣中有大量溶酶体分布。扫描电镜显示血管附壁血栓形成多,血管内中性粒细胞活化程度重,与血管壁粘附现象多见。结论:地塞米松保护皮瓣与其减少中性粒细胞坏死数量,增加其凋亡水平有关。

CObjective: To Study histopathology of the ischemia-reperfusion island flaps, investigating the role of neutrophil and explaining the protection mechanisms of the dexamethasone. Methods:Wistar rats were divided into two groups ( treatment and control groups ), island skin flaps model with ischemia -reperfusion was made. Skin flap viability was measured and biopsies were studied. Results: Flap survival areas of treatment group were more than that of the control. The treatment group had less leucocytes, more efflent vessels under light microscope; Less necrosis, more apoptotic neutrophil and normol capillary structure under transmission electron microscope; Slight active leucocytes and less adhesion with effluent vessels on scanning electron microscope .The control group showed more leucocytes in the flap within 1 days reperfusion. Leucocytes disappeared on 5 days under light microscope. Also, on 1 day, more thrombus formation was found in flap's vessels. More necrosis and less apoptotic neutrophil was observed, however, on 3 days , neutrophils decreased obviously , at the same time, more lysosomes appeared in the flap on transmission electron microscope. Lots of thrombosis, severe active leucocytes in vessels and more leucocytes adhesion with vessels were found on scanning electron microscope. Conclusion: Dexamethasone preventing flap from ischemia -reperfusion is correlated with its modulating leucocytes function, decreasing necrosis neutrophil and increasing its apoptotic level.