Effect of enalapril on gp130 gene expression of left ventricule in rats with experimental myocardial infarction

Objective: To study the relationship between left ventricular remodelling (LVRM) and the abnormal expression of gp130 mRNA in non-infarcted zone of left ventricule (LVNIZ) in rats with AMI, also to evluate the effect of enalapril on gp130 expression. Method: The 73 surviving AMI male Wistar rats were randomly divided into 2 groups at 24 hours after MI: AMI group and enalapril group, the former was subdivided into 6 groups according to different interval at 1, 3, 7,14,21,28 days after MI. Enalapril was delivered by direct gastric gavage (10 mg·kg -1·d -1) for 4 weeks beginning at the 2nd day after AMI. Sham-operated and normal rats were selected randomly to serve as non-infarcted controls. LVRM was evaluated by pathologic analysis, AngⅡand hydroproline concentration (HC) in LVNIZ were measured by radioimmunoassay and chloramine T method respectively. The mRNA level of gp130 in LVNIZ were determined by RT-PCR. Complete experimental data were obtained in 76 rats, being 9, 8, 8, 9, 9, 8, 9, 8 and 8 respectively in each group mentioned above. Results: ①Compared with sham-operated rats and control rats, heart weight (HW), left ventricular weight(LVW), left ventricular weight index(LVWI), TDM, HC in the 28th day after MI group were all significantly increased (P 0.05～ 0.01). ②LVNIZ AngⅡwere significantly increased after MI and correlated well with LVRM(P 0.01). ③The mRNA level of gp130 in LVNIZ gradually increased as early as the 1st day after MI, peaked at the 7th day and declined thereafter, but sustained higher than those in sham-operated rats in the 28th day after MI (P 0.05～ 0.01). ④Correlated analysis found that there were significant positive correlation between gp130 mRNA level,myocardial AngⅡas well as LVRM parameters (P 0.05～ 0.01). ⑤Myocardial AngⅡ and gp130 mRNA expression were all decreased in enalapril-treated group with lightened LVRM comparing with the 28th day after MI group(P 0.05～ 0.01). Conclusion: Overexpression of gp130 in LVNIZ may play an important role in LVRM after MI, the mechanisms of enalapril preventing LVRM may be partly through depressing gp130 overexpression, which is worth studying further.