大鼠双后肢挤压伤局部肌组织NO变化及其作用

目的探讨大鼠双后肢挤压伤局部肌组织NO含量变化及其在肌组织损伤中的可能作用。方法应用大鼠双后肢挤压伤模型。实验动物随机分为对照(S)组、挤压(C)组、挤压并舌下注射氨基胍(AG)组(A组)、挤压并舌下注射L-精氨酸(L-Arg)组(L组)。用比色法检测局部肌组织和血清NOS活性、NO含量,免疫组化法检测局部肌组织eNOS、iNOS蛋白表达,测量局部肌组织湿干质量比值(W/D),并观察肌组织的组织病理学改变。结果与S组相比,C组双后肢挤压引起局部肌组织明显损伤,肌组织W/D明显升高(P<0.01),肌纤维溶解,血管扩张、淤血、出血、间质水肿等继发性损伤,肌组织中eNOS和iNOS蛋白表达上调,NOS活性增加(P<0.01),NO含量增加(P<0.01);相关分析表明,肌组织W/D与NO含量呈显著正相关,在A组和L组,应用AG和L-Arg分别导致肌损伤(如肌组织W/D)减轻和加重。血清中NOS活性和NO含量变化大致与肌组织类似。结论挤压大鼠双后肢可诱导局部肌组织eNOS和iNOS蛋白表达上调,NOS活性增加,NO生成增多;NO生成增多介导了局部肌组织继发性损伤。

Change of nitric oxide in local muscle of crush injury hind-limbs in rats

Objective To investigate the change of nitric oxide (NO) level in local muscles induced by crushing hind-limbs in rats. Methods The rat experimental model of hind-limb crushing injury was established by crushing the hind limbs of rats with standard weight for 5 hours, thereafter releving the standard weight for another 5 hours. The rats were randomly divided into sham group, crushing group, crushing and injecting aminoguanidine (AG) group, crushing and injecting L-arginine (L-Arg) group.The NOS activity and NO level in local muscles and serum were spectrophotometrically measured, and iNOS and eNOS protein expressions in local muscles were examined by immunohistochemistry. The weight ratio of wet to dry (W/D) of local muscles was measured and the pathologic changes were observed. Results The crushing hind-limbs induced serious primary and secondary injuries of local muscles such as rupture and rhadomyolysis of skeletal muscular fibers,interstitial vascular congestion and edema,and marked increase in W/D.The expressions of eNOS and iNOS were upregulated in local muscle in crush group compared with sham group.The NOS activity and NO level in local muscles and serum significantly increased. There was positive relationship between NO level and W/D in local muscles. With the usage of AG and L-arg,the hind-limb injuries seemed alleviated and aggravated, respectively. Conclusion The crushing hind-limbs of rats elicited the upregulation of eNOS and iNOS protein expression, the enhancement of NOS activity and the excess production of NO, the latter of which was involved in the mediation of secondary pathological changes in local muscles.