严重烧伤早期腓肠肌损伤的形态学改变及其机制的初步探讨

Morphological changes and their mechanism of gastrocnemius muscle damage following early severe burn in rats

目的 探讨严重烧伤早期腓肠肌损伤及其发生机制。方法 应用光、电镜、组织化学染色及分光光度比色法对远离大鼠 3 0 %TBSAⅢ度烧伤部位的腓肠肌组织的病理变化 ,琥珀酸脱氢酶 (SuccinatedehydrogenaseSDH)、乳酸脱氢酶 (Lacticdehydroge naseLDH) ,一氧化氮 (NitricoxideNO)、黄嘌呤氧化酶 (XanthineoxidaseXO)、髓过氧化物酶 (MyeloperoxidaseMPO)及丙二醛 (Melondialde hydeMDA)的含量或活性进行一系列动态观测。结果 严重烧伤后腓肠肌肌纤维嗜酸性染色增强、肌纤维肿胀、横纹消失、肌浆溶解。电镜下核周基质水肿 ,Z线扭曲或中断 ,肌原纤维灶性溶解、线粒体肿胀或空化 ,肌浆网扩张和糖原颗粒减少。烧伤后 6～ 2 4hSDH活性进行性降低 ;而LDH活性在伤后 1～ 12h进行性增加 ,以后逐渐下降。NO、XO、MPO及MDA含量或活性分别在伤后 6、6～12、2 4、12～ 2 4h与相应正常对照组差异显著。结论 严重烧伤后腓肠肌也是受累的主要组织之一。能量生成减少、NO产生、XO活化。

Objective To explore the damages of gastrocnemius muscle following severe burn and their mechanism. Methods A total of 30 rats were subjected to 30%TBSA Ⅲ degree burn on the back and another 10 served as normal control. Dynamic changes of activity or contents of succinate dehydrogenase (SDH), lactic dehydrogenase (LDH), nitric oxide(NO), xanthine oxidase (XO), myeloperoxidase (MPO), melondialdehyde(MDA) and pathological changes in the gastrocnemius muscle which was far from burn site were measured with histochemical staining, spectrophotography and light and electronic microscopy respectively. Results Reinforcement of acidophilic staining, swelling, extinction of stria, and lysis of sarcoplasm of muscle fiber in the gastrocnemius muscle were found following severe burn. Stroma edema around nuclei, distortion or breaks of Z lines, focal lysis of myofibrils, swelling or cavitation of mitochondria, dilatation of sarcoplasmic reticulum and reduction of granule particles were seen under electron microscope. The activity of SDH was progressively decreasing during 6th-24th hour while that of LDH progressively increasing during 1st-12th hour and then declined gradually. There was significant difference of actiivities or contents of NO, XO, MPO and MDA between normal control and burn group at the 6th, 6th-12th, 24th, 12th-24th hour respectively after severe burn. Conclusion Results show that gastrocnemius muscle is one of the main damaged organs after any severe burn. Decrease of capacity generation, development of NO, activitation of XO, infiltration of neutrophils and lipid peroxidation may play an important role in damage of gastrocnemius muscle following severe burn.