OBJECTIVETo investigate the modulation effects of mesenchymal stem cells (MSCs) implantation on the collagen remodeling in myocardial infarction.

METHODSAcute myocardial infarction (AMI) was induced in SD rats by left anterior descending coronary artery ligation, and the animals were assigned randomly into the Sham group, MI + PBS group and MI + MSCs group. Echocardiography and hemodynamic examinations were performed to evaluate the cardiac function. HE staining and Masson trichrome staining were used to evaluate the myocardial infarction size. Infarcted area and infarcted expansion index were calculated. The expression of collagens in infarcted hearts was evaluated by immunohistochemistry, RT-PCR and Western blot.

RESULTS(1) Infarct area was significantly reduced post MSCs transplantation [MI + MSCs vs. MI + PBS: (38.27 ± 2.70)% vs. (46.20 ± 3.17)%, P < 0.001]. (2) Cardiac function was significantly improved post MSCs transplantation [MI + MSCs vs. MI + PBS: FS(%): 29.98 ± 4.50 vs. 23.43 ± 3.34, P = 0.005; LVSP (mm Hg, 1 mm Hg = 0.133 kPa): 113.63 ± 10.81 vs. 99.25 ± 16.76, P < 0.05; LVEDP (mm Hg): 12.10 ± 4.28 vs. 20.08 ± 4.26, P < 0.05; +dp/dtmax (mm Hg/s): 4616.63 ± 363.34 vs. 3912.75 ± 248.79, P < 0.05; -dp/dtmax (mm Hg/s): 4254.63 ± 324.34 vs. 3530.88 ± 309.71, P < 0.05]. (3) Collagen synthesis was enhanced in infarcted area and decreased in non-infarcted area post MSCs transplantation (P < 0.05).

CONCLUSIONSMSCs transplantation could enhance the collagen synthesis in infarcted area while decrease the deposition of collagen in non-infarcted area in this MI model. This may be one of the mechanisms by which ventricular remodeling is attenuated post MSCs transplantation.