Abstract
In hypertensive rats at 615 weeks after bilateral constriction of renal arteries, the mesenteric arteries grossly presented nodose appearance (periarteritis nodosa) and histologically showed fibrinoid degeneration. These animals were intravenously injected with I131-labeled rat plasma protein, I131-labeled rat or bovine fibrinogen, radioacive chromic chloride (Cr5·Cl3 ; for the purpose of labeling plasma protein with Cr51 in vivo), or radioactive colloidal suspention of metallic gold (Au198), and degree of insudation of these proteins or colloidal gold into arterial wall was investigated by measuring radioactivity of the mesenteric arteries in three ways with the following results :
1) Determination with a scintillation counter revealed remarkably higer radioactivity in the mesenteric arteries of hypertensive rats with bilaterally constricted renal arteries than in those of normal controls, indicating that a large amount of I 131-plasma protein, I131-fibrinogen, Cr51-plasma protein, or colloidal Au198 had insudated into arterial wall of the former.
2) Microautoradiographs disclosed high radioactivity restricted to nodose lesions which represent fibrinoid degeneration.
3) Microautoradiographs showed radioactivity in areas of fibrinoid degeneration and edematous lesions in the intima and media, indicating the presence of I131-fibrinogen or I131-Plasma protein in these lesions.
It was concluded that the permeabilily of the blood-arterial wall barrier was markdly increased in rats with bilaterally constricted renal arteries, and that in arterial fibrinoid degeneration there was conspicuous insudation of blood plasma protein and fibrinogen into the arterial wall, and in fibrinoid substanse these proteins were present as its constituents.
