Abstract
By a modification of the Byrom's method, forceful repeated injections of physiological saline or 7% gum arabic-added physiological saline (having the same viscosity with blood) was made in rats through the left carotid artery toward the aorta in order to elicit sudden rise of intra-arterial pressure.
As the result, fibrinoid degeneration and medial necrosis were found in arteries of the kidneys, pancreas and mesentery. These lesions were quite different from each other. Namely, the former was stained dark blue with PTAH (phosphotungstic acid hematoxylin), negative in fat stain, and originally developed in the intima, while the latter was unstained with PTAH, positive in fat stain, and derived from degeneration and necrosis of medial smooth muscle cells.
In arteries of animals survived a long period (4-6 weeks), after the injections, fibrocellular intimal thickening was found as a sign of healing of the fibrinoid degeneration.
When unilaterally nephrectomized rats were given 1 % saline solution as drinking water for one year, hypertension was occurred, and fibrocellular intimal thickening and fibrinoid degeneration were seen in arteries of the mesentery and kidneys.
It was concluded that fibrinoid degeneration, medial necrosis and fibrocellular intimal thickening were experimentally produced in arteries by abrupt elevation of intra-arterial pressure.
