大鼠严重体表烫伤后骨骼肌蛋白酶作用研究

A Study of Protease Activity in Skeletal Muscle after Severe Burn Injury in Rats

为探讨严重烧伤早期负氮平衡发生机制,利用包括一侧后肢的37％大鼠体表面积全皮层烫伤模型,观察受伤肢体与未伤肢体比目鱼肌蛋白分解率的变化及相应肌肉几种蛋白水解酶可溶性部分活性改变。同时观察了胰岛素和β-羟基丁酸钠(β-HOBNa)对这些蛋白酶的效应。 烧伤后第3天结果表明,烫伤肢体比目鱼肌蛋白分解率及蛋白酶可溶性部份活性显著升高;胰岛素有降低组织蛋白酶活性的作用;β-HOBNa无此效应。 上述结果提示:严重体表烧伤早期受伤部位肌肉蛋白分解加快乃局部组织蛋白酶活性上升所为。胰岛素的节氮作用可能与抑制了这类蛋白酶的活性有关。

In order to clarify the mechanisms of the occurrence of negative nitrogen balance in the early period after severe burns, full thickness burns of 37% TBSA was inflicted on the back and one hind leg of the rats by scalding and then protein degradation rate and the activities of cathepsins B, H, and L, cathepsin D, and neutral protease were studied in the soleus muscle of the scalded and healthy legs. The effects of a large dose of intraperitoneal insulin and Na-DL-3-hydroxybutyrate on these proteases were also observed respectively.It was found that on the 3rd day after injury, the protein degradation rate and the ac tivities of cathepsins B, H,and L, cathepsin D, and neutral protease increased significantly in the soleus of the scalded limb, but no similar changes could be seen in those of the healthy limd and in the contro. 1 An intraperitoneal injection of insulin significantly inhibited the activities of cathepsins B, H, L and D.These findings suggest that cathepsins play an important role in the protein degradation of the injured skeletal muscle in the early stage of severe burns and are one of the causes of negative nitrogen balance. Insulin can be protein -sparing because of its inhibition on cathepsins although there may be insulin resistance in scalded rats.