Changes in the biomechanical properties of skin and aorta induced by corticotrophin treatment

Abstract

The effect of elevated levels of corticosteroids on the biophysical properties of skin, aorta and muscle tendon was investigated. Rats were given ACTH injections for 10, 30 and 60 days to elevate the level of plasma endogenous corticosteroids. The ACTH treatments did not change the H2O or collagen content of specimens from dorsal skin, thoracic aorta and peroneal muscle tendons, tested mechanically. For both skin and aorta, the tensile strength, elastic stiffness and failure energy were increased after 60 days of treatment. The ACTH treatment did not influence the mechanical properties of muscle tendons. Complete reversibility of changes in the mechanical properties induced by 30 days of ACTH treatment was found after an additional period of 30 days of saline injections. An increased level of plasma corticosteroids elicited by ACTH treatment may increase the stiffness of the connective tissue of the organism. In the aorta this results in loss of capacitive function with increased hemodynamic strain on the aortic wall.