The dynamic change of TGF-β₁ in the myocardial remodeling of rat after myocardial infarction

Abstract

To observe the dynamic changes of the TGF-β₁ expressed in the infarct and non-infarcted region of rat heart during the ventricular remodeling (day 3, 7, 28, 180), myocardial infarction rat model was made and relationship between the cytokine and indicator of myocardial remodeling was analyzed. After the detection of hemodynamic parameter was performed by the Powerlab devices, the size of myocardial infarction and the morphology change was detected by TTC and HE, respectively. The relative levels of mRNA of TGF-β₁, collagen type I, III, and fetal gene beta-MHC were detected by RT-PCR. The distribution of TGF-β₁ protein in the myocardium was detected by immunohistochemistry. The results showed that the size of infarction was higher than that of the sham operated groups in the infarcted group (44.5±0.5 vs 0). The difference in hemodynamic parameters between the infarcted group and sham operated group was significant (P<0.01). HE staining showed that inflammatory cells were accumulated in the infarcted region at the beginning of the 3^rd day, which lasted 4 weeks. Then, it decreased gradually. β-MHC in the non-infarcted region rose from the 3^rd day, reaching its peak at the 4^th week, and it decreased gradually. The ratio of the collagen type I/III showed similar changes as compared with the sham operated groups (P<0.01). And the relative mRNA levels in the non-infarcted group were significantly higher than that in the infarcted and sham operated group (P<0.01) at day 180. Linear regression analysis indicated that the TGF-β₁ was positively correlated with the ventricular remodeling. It was concluded that the cytokine TGF-β₁ participates in the process of the myocardial remodeling, which could be a strategy in the interference of myocardial remodeling.

Keywords

myocardial remodeling / fetal gene / cytokine

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