Pioglitazone administration combined with bone marrow mesenchymal stem cells transplantation improved the heart function of rats with myocardial infarction / 中国组织工程研究

ABSTRACT

BACKGROUND:Our previous work has demonstrated that bone marrow mesenchymal stem cels (BMSCs) transplantation can improve the heart function of rats with myocardial infarction. However, the overal efficacy is not satisfactory. OBJECTIVE: To adopt pioglitazone as a peroxisome proliferator-activated receptor gamma (PPAR-γ) agonist combined with BMSCs transplantation therapy, thereby further improving cardiac function of rats with myocardial infarction as wel as investigating the relevant mechanisms. METHODS:Twenty Sprague-Dawley rats with myocardial infarction were induced by the left anterior descending coronary artery ligation. The animals were randomized into two groups BMSCs and BMSCs+pioglitazone. Two weeks later, al the animals received the injection of BMSCs labeled with PKH26 in PBS into the local infarct zone, and then pioglitazone (3 mg/kg/d) was given by the oral gavage for 2 weeks in the BMSCs+pioglitazone group after the cel transplantation. After 2 weeks of cel transplantation, cardiac functions were evaluated by echocardiography. The expressions of PPAR-γ, Connexin 43 and molecules in TGF-β1/SMAD signaling pathway were examined in different areas of the left ventricle from each harvested heart using immunofluorescent staining, western blot assay and qRT-PCR. RESULTS AND CONCLUSION:There were no differences in the baseline parameters of cardiac function between the two groups. At 2 weeks after cel transplantation, the left ventricular internal diameter at end-diastole, left ventricular internal diameter at end-systole and left ventricular ejection fraction were significantly improved in the BMSCs+ pioglitazone group; the expressions of PPAR-γ and Connexin 43 were distinctly increased in different zones of the left ventricle; the levels of TGF-β1, SMAD2 and SMAD3 were obviously attenuated in the infarct zone and border zone. The above-mentioned findings suggest that pioglitazone, a PPAR-γ agonist, can enhance BMSCs potential in improvingthe heart function after myocardial infarction, and PPAR-γ may elevate the expression of Connexin 43via the blockade of the TGF-β1/SMAD signaling pathway in the procedure.