[Effects of overexpression of human tissue inhibitor of metalloproteinase-1 on the inflammatory response in rats with myocardial infarction and related mechanisms].

Objective: To observe the effects of recombinant adenovirus with human tissue inhibitor of metalloproteinase-1(Ad-hTIMP-1) on the inflammatory response in rats with myocardial infarction (MI) and explore the related mechanisms. Methods: The male Wistar rats were randomly divided into sham-operated group, saline group, Ad-Track group and Ad-hTIMP-1 group according to the random number table (n=8 each group). MI was induced by ligation of the left anterior descending coronary artery and MI rats were injected with saline, Ad-Track and Ad-hTIMP-1, respectively. Sham-operated rats received similar surgical procedure without ligation of the left anterior descending coronary artery. After 4 weeks, the cardiac function was measured by echocardiography, then rats were sacrificed and hearts were removed for morphological and biological analysis. The morphology of myocardial tissue in each group was detected by HE staining and Masson staining. The mRNA expressions of tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-10 and C-reactive protein(CRP) were detected by real-time PCR. Immune histochemical staining was performed to observe the protein expression levels of IL-6 and CRP. Results: (1) Left ventricular end systolic dimension derived from echocardiography was increased in saline group ((5.10±0.72) mm) and Ad-Track group ((4.88±0.64) mm) compared to sham-operated group ((4.25±0.46) mm), which was reduced in Ad-hTIMP-1 group ((4.13±0.35) mm, all P<0.05). The left ventricular ejection fraction was (72.46±5.74)%, (64.27±8.52)%, (64.65±3.90)%, and (71.55±6.95)%, the fractional shortening was (36.90±4.97)%, (29.03±3.40)%, (30.95±2.51)%, and (36.31±5.68)% in sham-operated group, saline group, Ad-Track group and Ad-hTIMP-1 group, respectively. The left ventricular ejection fraction and fractional shortening in saline group and Ad-Track group were lower than those in sham-operated group and Ad-hTIMP-1 group (all P<0.05). (2) Necrosis of myocardial cells was not found and a small amount of immune cell infiltration and interstitial fibrosis were observed on HE and Masson stained myocardial sections of Ad-hTIMP-1 group. (3) Real-time PCR showed that mRNA expressions of TNF-α, IL-6, IL-10 and CRP were lower in Ad-hTIMP-1 group than in saline group. mRNA expressions of TNF-α, IL-10 and CRP were lower in Ad-hTIMP-1 group than in Ad-Track group (all P<0.05). (4) Immune histochemical staining showed that protein expressions of IL-6 and CRP were higher in saline group and Ad-Track group than those in Ad-hTIMP-1 group (all P<0.05). Conclusion: Recombinant adenovirus Ad-hTIMP-1 can improve cardiac function in rats with myocardial infarction via inhibiting the inflammatory response and downregulating the expression of TNF-α, IL-6 and CRP.