抄録
Influences of ascorbic acid (vitamin C) deficiency on the aorta and serum lipids were studied. Guinea pigs weighing about 300 grams were made ascorbic acid deficiency by scorbutic diet feeding.
1. Alteration of the aortic endothelium by manifest ascorbic acid deficiency, scurvy were investigated with Hautchen preparation, electron microscopy and frozen surface preparation for fibrinolytic activity according Warren. Aortic endothelium displayed reduced silver stainability of the cement line and an increased incidence of nuclear changes as vacuolization, swelling, distortion and pyknosis in Hautchen preparation (Fig. 2). Electron microscopy revealed separation of the endothelial junction and reduction of cytoplasmic organelles, and also a depletion of subendothelial collagen (Fig. 3). These findings indicate that ascorbic acid deficiency induces not only capillary alteration but also injury of the aortic endothelium. Fibrinolytic activity of the endothelium as an index of endothelial function was not changed by ascorbic acid deficiency, but displayed a gradient which increased from the arch to the abdominal segment of the aorta (Table 1).
Regional difference of the endothelial fibrinolytic activity may contribute to local difference on distribution of atherosclerosis.
2. Influcence of ascorbic acid deficiency on serum lipids and the aorta were studied. Male guinea pigs were fed with scorbutic diet with or without 5% coconut oil in weight for two weeks. Content of serum lipids, lipoprotein lipase activity and morphorogical change of the aorta were investigated. Serum triglyceride and cholesterol ester were moderately increased in ascorbic acid deficient guinea pigs, and markedly to twice of the normal control in the ascorbic acid deficiency with coconut oil feeding. Depression of plasma lipoprotein lipase activity was observed by ascorbic acid deficiency of both with and without coconut oil feeding. Histological examination of the aorta revealed edematous swelling of the ground substance in the intima and media in the scorbutic, and early atheromatous lesions of accumulated foam cells in the intima of the ascorbic acid deficiency with high fat diet (Fig. 4).
These findings suggest that ascorbic acid deficiency induces alteration of the aortic endothelium and increase of serum lipids and altered vascular wall connective tissue metabolism and consequently follow atherosclerosis.
