This study was designed to test the effectiveness of dietary retinol in pro
tecting the heart and lung parenchyma in a monocrotaline model for lung inj
ury and pulmonary hypertension in rats. Male rats were assigned to three gr
oups. Two groups were injected subcutaneously with monocrotaline (17 mg/kg
body weight) and fed either the control AIN-93G diet (MC) or the control di
et supplemented with retinol (17 mg retinyl palmitate/kg diet)(MR). The thi
rd group was fed the control diet and injected with the vehicle only (VC).
Four weeks after monocrotaline treatment, the MR group had less thickening
of the alveolar septal wall, less myocardial inflammation and degeneration
of the right ventricle, and less vascular inflammation in the lung compared
with the MC group. The supplemented dietary retinol, however, did not prev
ent development of right ventricular hypertrophy and did not affect the syn
thesis and secretion of surfactant phospholipids in type II pneumocytes. Th
e results indicate that dietary retinol suppresses the inflammatory respons
es in the heart and lungs of rats treated with monocrotaline.