Growth Factor Expression and Effects of Amrinone in Monocrotaline-Induced Pulmonary Hypertension in Rats

Abstract Platelet-derived growth factor (PDGF) and basic fibroblast growth factor (bFGF) have been implicated in myointimal proliferative arteriopathy, a lesion seen in monocrotaline-induced pulmonary hypertension (MIPH). The purpose of this study was to examine the expression of PDGF and bFGF in the lungs of rats given monocrotaline and to examine the effects of amrinone on the hearts and lungs of these rats. Twenty-four 26-day-old rats were randomized to receive either monocrotaline (≈3.6 mg/kg/d) or no monocrotaline and concomitantly to receive either amrinone (100 mg/kg/d) or no amrinone for 21 days. Lungs were examined for immunohistochemical evidence of PDGF and bFGF, and hearts were examined for effects of pulmonary hypertension and amrinone. Immunohistochemical staining of lungs showed no evidence of PDGF except in bronchioles. bFGF staining was similar between groups (no monocrotaline 25%, monocrotaline 27%, monocrotaline and amrinone 22%), and the staining was confined to the arterial walls. Rats given monocrotaline showed significantly greater right ventricular (RV) weight (0.13 ± 0.02 g versus 0.23 ± 0.04 g [mean ± SD], P P P