The dynamic change of TGF-beta1 in the myocardial remodeling of rat after myocardial infarction.

To observe the dynamic changes of the TGF-beta1 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- beta1, collagen type I, III, and fetal gene beta-MHC were detected by RT-PCR. The distribution of TGF- beta1 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 3rd day, which lasted 4 weeks. Then, it decreased gradually. beta-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-beta1 was positively correlated with the ventricular remodeling. It was concluded that the cytokine TGF-beta1 participates in the process of the myocardial remodeling, which could be a strategy in the interference of myocardial remodeling.