Abstract
The thyroid gland is regarded as one of the most closely related visceral organs to the metabolic activity of the man. The author has investigated the arteriosclerotic process, involving the vessels distributing in the thyroid gland and clarified the fact that the definite differences in extension and severity of the arteriosclerosis between thyroid gland and other visceral organs. The present investigation was dealt with the light and electron microscopic observation of the arteries, distributing in the thyroid gland.
The materials were divided into two groups. The first group consisted of 81 cases, aged of the glands which showed no thyroid disease and were served as control. They w0e. r9e2, varied in ages. The second group consisted of 69 cases which showed clinical evidences for hyperthyroidism.
A experimental study, using rats has been installed. One unit of thyroid stimulating hormone (TSH) had been intramuscularly given to induce the hyperthyroidism, and 0.1mg of methimazole was orally given for two weeks to induce the hypothyroidism. Simultaneously, the rats of various age groups were investigated.
The arteries measuring 10 to 300μ in diameter were mainly investigated.
Interestingly enough, the extent of the arteriosclerosis in the arteries, distributing in the thyroid gland remained to be lesser extent in comparison with general visceral arteries. Ultrastructurally, in the hyperthyroidism the arteries were induced in striking development of the vesicular system as well as swelling and hyperplasia of the endothelial and the medial cells. Inter-cellular matrix revealed increases of elastic fibrils and increase of ruthenium red positive mucopolysaccharide which showed no definite periodicity and polarity.
More impressively, the vesicles in the medial cells contained tannic acid stain positive high density materials which might be liberated into the cellular matrix and might be justifiable as ultrastructural evidence for elastic and collagenous fibril formation.
In the comparative study of arteriosclerosis in aging, the arteries showed decrease of elastic fibrils in the intercellular matrix, while the collagenous fibrils tended to increase as the age proceed.
In this study, it was demonstrated that a lesser extent of arteriosclerosis, increase of elastic observed compared with the other visceral organs. More remarkable changes found in the hyperthyroidism.
These findings might be due to the specificity of the anatomical vascular distributing pattern and the indirect action of thyroid hormone to the intermediated metabolism.
