The Dynamic Change of TGF-β1 in the Myocardial Remodeling of Rat after Myocardial Infarction

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 de- tected by RT-PCR. The distribution of TGF-β1 protein in the myocardium was detected by immuno- histochemistry. The results showed that the size of infarction was higher than that of the sham oper- ated groups in the infarcted group (44.5±0.5 vs 0). The difference in hemodynamic parameters be- tween 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 3rd day, which lasted 4 weeks. Then, it decreased gradually. β-MHC in the non-infarcted region rose from the 3rd day, reaching its peak at the 4th 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 posi- tively correlated with the ventricular remodeling.It was concluded that the cytokine TGF-β1 par- ticipates in the process of the myocardial remodeling, which could be a strategy in the interference of myocardial remodeling.