急性心肌梗死大鼠胃排空变化与C-型利钠多肽的关系

Relationship between gastric emptying delaying and C-type natriuretic peptide after acute myocardial infarction in rats

目的探讨急性心肌梗死（AMI）大鼠胃排空变化与C-型利钠多肽（CNP）的关系。方法对12只AMI大鼠模型（AMI组）和9只假手术大鼠（假手术组）用99^m-Tc-DTPA标记的面粉糊灌胃后，分别在单光子发射计算机断层照相仪下进行胃排空功能检查；50min后处死AMI组大鼠，氯化-2，3，5-三苯基四氮唑染色法计算心肌梗死面积；同时取AMI组和假手术组大鼠各9只测定血浆CNP浓度，免疫组织化学法测定胃窦平滑肌CNP免疫阳性细胞的分布和含量变化。结果AMI组胃半排空时间为（23．1±4．7）min，50min胃内核素残留率为（27．6±4．5）％，假手术组胃半排空时间为（16．0±4．0）min，50min胃内核素残留率为（18．1±3．3）％，AMI组胃半排空时间较假手术组明显延长（P〈0．05），50min胃内核素残留率明显增多（P〈0．05）。AMI组心肌梗死面积为（52．1±4．1）％，与50min胃内核素残留率呈正相关（r=0．620，P=0．031）。AMI组、假手术组血浆CNP浓度分别为（70．6±0．4）、（65．2±9．3）ng／L，两组比较差异无统计学意义。结论AMI大鼠胃排空明显减慢，与血浆和胃窦平滑肌中的CNP无明确关系。

Objective To investigate the changes of gastric emptying in rats after acute myocar dial infarction, and to study its relationship with C-type natriuretic peptide （CNP）. Methods The male Wistar rats were submitted to thoracotomy followed or not by occlusion of the left coronary artery. After 24 h, acute myocardial infarction（AMI, n=12） and sham group（n=9） were gavage fed （1 mL） with 99m-Tc-DTPA labeled test meal. Half gastric emptying time and 50 min residual rates were measured by single photon emission computed tomography. The rats of AMI group were sacrificed after 50 min. Plasma level of CNP was measured by radioimmunoassay respectively in AMI and sham group. Results Half gastric emptying time significantly increased from （16.0±4.0） min in sham group to （23.1±4.7） rain in AMI group （P 〈0.05）, and 50 min residual rate significantly increased from （18.1±3.3）% in sham group to （27.6±4.5）% in AMI group （P 〈0.05）. Infarction area of AMI group was （52.1±4.1）%, and a positive correlation was found between infarction area and 50 min residual rate （r=0.620, P=0.031）. The plasma CNP of AMI group and sham group were （70.6±10.4） ng/L vs （65.2±9.3） ng/L. CNP did not enlarge significantly. Conclusion AMI delays the gastric emptying in rats, and there is positive correlation between infarction area and residual rate.