Background: Hepatocyte growth factor (HGF) inhibits the development of pulmonary artery hypertension (PAH) by reducing pulmonary artery pressure and right ventricle (RV) hypertrophy. However, whether HGF can prevent RV remodeling via inhibiting apoptosis in RV cardiomyocytes and decreasing neurohormonal activation remains unknown.
Methods: The PAH and subsequent RV remodeling in rats were induced by subcutaneous injection of monocrotaline (MCT). The PAH rats were transfected with adenovirus carrying HGF (Ad-HGF) via intratracheal instillation. Three weeks after transfection, the hemodynamics indexes were measured, serum levels for angiotonin II (ANG II) and brain natriuretic peptide (BNP) were determined by ELISA. Histological analysis was used to assess the RV hypertrophy and fibrosis. The cardiomyocyte apoptosis in RV was assayed by TUNEL staining. The mRNA expression of BNP, angiotensin-converting enzyme (ACE), Bax and Bcl-2 in RV was determined by reverse transcriptase polymerase chain reaction (RT-PCR), the protein expression of transforming growth factor (TGF)-β1 and tumor necrosis factor (TNF)-α in RV was determined by Western blotting.
Results: HGF treatment significantly decreased the mean PAH, RV systolic pressure, serum ANG II and BNP levels. HGF treatment also significantly decreased the RV hypertrophy, collagen deposition, and the number of apoptotic cardiomyocytes. Moreover, HGF treatmemt significantly decreased the expression of BNP, ACE, Bax, TGF-β1, and TNF-α, while it significantly increased the expression of Bcl-2.
Conclusions: Gene transfer of HGF decreases MCT-induced PAH and improves RV remodeling. This effect is mediated not only by improving the hemodynamics but also by decreasing neurohormonal activation and inhibiting cardiomyocytes apoptosis. HGF gene treatment may be an effective strategy for improving RV remodeling in MCT-induced PAH.