A Histopathological and Histochemical Study of Experimental Atherosclerosis in Rabbit Report II

Abstract

Auther attempted to analyze the relationship between the atherosclerosis and the function of the thyroid glands, and coronary arteries, arteries of choroid plexus and endocrine glands of the rabbits ultilized in previous experiment (Report I) were studied histopathologically.
The following results were obtained:
No atherosclerosis (intimal fatty necrosis) was recognized in the coronary arteries and arteries of choroid plexus of th rabbits which were received lanolin feeding for 12 months, and they showed only the fatty streaks in the intimal tissue. Remarkable atherosclerosis were observed in the intimal tissue of the coronary arteries and arteries of choroid plexus of the rabbits which were received thyroidectomy followed by lanolin feeding for 6 months or 12 months. A small atheromatous lesion were recognized in the coronary artery of the thyroidectomized rabbit which received lanolin feeding and thyroxin injections for 6 mouths, after they had been maintained on a lanolin feeding for 6 months, however, proliferation of intimal spindle shaped cells were seen around and within the atheromatous lesion, and these cells did not show any regressive changes. It will be considered that these intimal spindle shaped cells have a role of reparative adsorbtion of the atheromatous necrotic substance.
These observation indicate that intimate associations between atherosclerosis and the functional state of thyroid glands exist.
Deficieney of thyroid hormone induce athrosclerosis by means of lanolin feeding in the rebbit artery, and the thyroid hormone supplementation caused a disappearance of the atheromatous lesions from rabbit artery, however, did exhibit reparatory changes, characterized by intimal fibrosis.
The observations concerning with endocrine glands were as follows:
In the rabbits received only lanolin feeding, the thyroid glands exhibited findings of hyperfunctional state, a slight proliferation of chromophobe cells and alfa cells were also recognized in hypophysis, hyperplasia of islets cells of Langerhans were seen in pancreas, and the cortex of adrenal glands showed slight atrophy. When the animals were received thyroidectomy and lanolin feeding, remarkable proliferation of chromophobe cells and beta cells were seen in hypophysis. Hyperplasia of islets cells of Langerhans were seen in the pancreas, and atrophy of the cortex of adrenal glands were also found in this group. In the thyroidectomized rabbits received lanolin feeding and thyroxin injection after they had been maintained on a lanolin feeding, chromophobe cells and beta cells of hypophysis, islets cells of Langerhans of pancreas whih had proliferated in the period of lanolin feeding were exhibited observations of gradual atrophy by thyroxin supplementation.