Activation of peroxisome proliferator-activated receptor γ ameliorates monocrotaline-induced pulmonary arterial hypertension in rats

Activation of peroxisome proliferator-activated receptor γ (PPARγ) suppresses the proliferation of pulmonary artery smooth muscle cells (PASMCs) and vascular remodeling in rats and humans, and therefore improves the development of pulmonary arterial hypertension (PAH). However, molecular mechanisms underlying these effects have not been completely understood. In the present study, the effects of PPARγ activation in monocrotaline (MCT)-induced pulmonary artery remodeling in rats were investigated. Eighteen Sprague-Dawley (SD) rats were randomly assigned into three groups (n=6): Control (Con), PAH and PAH treated with rosiglitazone (MCT + Rosi). The right ventricular systolic pressure (RVSP), the ratio of the right to left ventricle plus septum weight [RV/(LV + S)], the percentage of medial wall thickness (%MT) and wall area (%WA) were used to evaluate the development of PAH. Tissue morphology was measured using hematoxylin and eosin staining. The protein levels of the phosphatase and tensin homologue deleted on chromosome ten (PTEN), Akt (ser473) phosphorylation (p-Akt) and total Akt in intrapulmonary arteries were determined by western blot analysis. MCT treatment significantly increased the RVSP, which was reduced by rosiglitazone treatment. The ratio of RV/(LV + S), %MT and %WA induced by MCT were similarly inhibited, which was associated with the increase of PTEN expression and the inhibition of Akt phosphorylation levels by rosiglitazone. In conclusion, activation of PPARγ ameliorates the proliferation of PASMCs and vascular remodeling by regulating the PTEN/PI3K/Akt pathway, suggesting that the activation of PPARγ has potential benefits for PAH.