Histological changes of the aging aorta in male albino rat

Introduction Aging represents a major risk for vascular diseases. Diseases of the aorta exert serious effects on the heart. Aim This study aimed to detect the histological changes of the aged aorta, understand their underlying mechanisms, and help in the development of prophylactic and treatment measures. Materials and methods Ten adult and 10 aged male albino rats were used. Specimens from their thoracic aorta were prepared and stained with hematoxylin and eosin, with orcein for elastic laminae, and with antiactin antibody. Morphometric measurements for the thickness of the tunica intima and elastic laminae of the tunica media were taken. Results Aged aorta showed thickening of the tunica intima, thinning and fragmentation of elastic laminae, proliferation of medial smooth muscle, reduction of their actin myofibrils, and fibrosis of the tunica adventitia. Atherosclerosis was also detected with epithelioid changes in the medial smooth muscle and focal thickening of the intima. Conclusion Aging is a risk factor for aortic atherosclerosis. Intimal thickening and proliferation of medial smooth muscle are the earliest signs. Thinning and fragmentation of elastic laminae, decreased contractile myofibrils of the aortic smooth muscle, and fibrosis of the tunica adventitia lead to aortic stiffness, which interferes with its active function and contributes to age-related arterial remodeling.