Effect of alloxan diabetes induced in spontaneously hypertensive rats.

Abstract

Spontaneously hypertensive rats and normotensive Wistar rats were divided into four groups: group I, non-treated normotensive rats; group II, normotensive rats with alloxan diabetes; group III, non-treated spontaneously hypertensive rats; and group IV, spontaneously hypertensive rats with induced alloxan diabetes. Changes in blood pressure and body weight were recorded once a week. Autopsies were performed three, six, nine, 12, and 18 months after the beginning of the experiment in several cases for histological examination of the heart, kidneys, and cardiovascular system and for histometric study of the pituitary, adrenal, and thyroid. 1) The body weight gain of the rats with diabetes mellitus was much less than that of the non-treated group. 2) The blood pressure fell temporarily when alloxan diabetes was induced, but it gradually rose to higher than in each control group: at 12 months, 152±4 mmHg in males and 142 ± 8 mmHg in females in group II; 202±8 mmHg in males and 193±4 mmHg in females in group IV; and 185±5 mmHg in males and 175±5 mmHg in females in group III. 3) (a) No histological abnormalities were noted in the heart, kidney or vascular system in group I. (b) The hearts and kidneys of group II rats were more hypertrophic than those of group I. Slight arteriosclerosis was found in the kidney. Diffuse glomerulosclerosis occurred in one rat at nine months, in two at 12 months and in two at 18 months, exudative lesions were also present in one of the rats at 12 months and in one at 18 months. (c) The hearts and kidneys of group III rats were more hypertrophic than those of group I. Mild arteriolosclerosis was found in the kidney, and cicatrix formation of the myocardium and coronary arterloslcerosis. (d) The hearts and kidneys of group IV rats were very hypertrophic, and cicatrix formation of the myocardium and coronary arteriosclerosis were more severe and frequent than in group II. Sclerosis of the renal arterioles started at nine months; diffuse glomerulosclerosis was noted in two rats at six months, in three at nine months in four at 12 months and in five at 18 months; nodular atypical lesions were also present in one of these rats at nine months, one at 12 months and three at 18 months. 4) The following histometric findings were observed in the pituitary, adrenal and thyroid in group IV: an increase in the number of basophile cells in the anterior lobe of the pituitary, an increase in their area, an increase in the area of the fascicular and reticular zones of the adrenals, and increase of the follicular area, follicular cell area and number of follicular cells in the thyroid. 5) These results indicate that, when alloxan diabetes is induced in spontaneously hypertensive rats, the endocrine abnormalities of both disorders multiply their effects in each other and cause the blood pressure to rise. When this serious situation of coexisting hypertension and the metabolic as well as endocrine disturbances of diabetes mellitus persists for a long time, it often results in severe arteriosclerosis and the diffuse and nodular lesions of diabetic glomerulosclerosis.