Exposure of rats to continuous light attenuates melatonin production and results in hypertension development. This study investigated whether hypertension induced by continuous light (24 hours/day) exposure induces heart and aorta remodelling and if these alterations are prevented by melatonin or angiotensin converting enzyme inhibitor captopril.
Exposure to continuous light led to hypertension, LV hypertrophy and fibrosis, and enhancement of the oxidative load in the LV and aorta. Increase in systolic blood pressure by continuous light exposure was prevented completely by captopril and partially by melatonin.
Both captopril and melatonin reduced the wall thickness and cross-sectional area of the aorta and reduced the level of oxidative stress. However, only captopril reduced LV hypertrophy and only melatonin reduced LV hydroxyproline concentration.