内毒素血症幼年大鼠心肌降钙素基因相关肽的动态变化及谷氨酰胺、地塞米松对其影响

Dynamic changes of myocardial CGRP in infancy rats with endotoxemia and effects of glutamine/dexamethosone on it

目的通过观察内毒素血症幼年大鼠心肌降钙素基因相关肽(calcitonin gene-related peptide,CGRP)的动态变化及谷氨酰胺(glutamine,Gln)、地塞米松(dexamethosone,Dex)对其影响,探讨CGRP对内毒素血症大鼠心肌的保护作用。方法选用健康18日龄Wistar大鼠128只,按腹腔注射药物不同分为:0h对照组(Ctrl:生理盐水,n=8),内毒素血症组(LPS:n=40)、谷氨酰胺组(Gln,n=40),地塞米松组(Dex,n=40),后3组又分为2、4、6、24及72h5个时点,每个时点8只,在各指定时点分别将大鼠断头分离心脏,用放射免疫方法测定心肌CGRP表达水平。结果1.与对照组比较,各组心肌组织内CGRP均下降,P<0.05～0.01;LPS组CGRP下降最明显,最低点在6h,Gln和Dex组最低点均后延至24h,Gln降低最轻,但3组最低点之间无显著差别,P>0.05。2.在内毒素血症早期,Dex组下降最慢,但在恢复期,Gln组恢复最快,虽明显高于LPS组,但仍显著低于0h对照组,P<0.05。结论Gln和Dex具有抑制CGRP下降的作用,其中Dex抑制早期CGRP下降作用较大,而Gln促进恢复作用更明显。

Objective： To observe the dynamic changes of myocardial CGRP in infancy rats with endotoxemia and examine the effects of glutamine and dexamethosone on it. Methods： Classical endotoxemia model were established by intraperitoneal injection of lipopolysarccharide （LPS） 4mg/kg, Escherichia coli 055：B5, Sigma. 128 Wistar 18 -day -rats were divided into four groups randomly, （ 1 ） Oh ctrl group （ Normal saline： 1 ml/kg, n = 8 ）, （2） LPS group （ LPS： 4mg/kg, n = 40）, （3） Gln group （ LPS. 4mg/kg and immediately 13. 64% Gln： lml/kg, Fresenus, n =40）, （4） Dex group （ LPS： 4mg/kg and immediately Dex 5mg/kg, n =40）, furthermore, LPS, Dex and Gln groups were divided into 2,4,6, 24 and 72 h time point （ n = 8 ）. Then sacrificed rats at appoint time, isolated the hearts, measure the level of CGRP of myocardial by Ridioimmunonity. Results ： （ 1 ） Comparing with 0 h, the expression of CGRP in LPS, Gln and Dex groups were significantly depressed, P 〈 0.05. In LPS group, decrease of CGRP is the most significant, the lowest is at 6h. then was Dex and Gln group, the lowest points in Gln group and Dex group were postponed to 24h, moreover, but there were no significant difference at the levels of CGRP among of them , P 〉 0.05. （2） At 72 h, the recovery of CGRP in Gln group was the fastest, it is significant higher than that in LSP, but which still obviously lower than that in Ctrl. Conclusion：Both Gln and Dex can prevent the decrease of myocardial CGRP in infancy rats with endotoxemia. To depress the decrease of CGRP, Dex was stronger than Gin at the acute couse, while Gin promote the recovery state much more than that in Dex.