Histological changes of the contralateral adrenal cortex following unilateral adrenalectomy in male albino rat

ABSTRACT

Unilateral adrenalectomy [UA] is performed not only to treat adrenal tumors but also as part of radical nephrectomy. The aim of the present study was to detect the effects of UA on the contralateral adrenal cortex, to identify the primary zone that was affected by adrenalectomy and the time at which the gland was histologically stabilized. Forty adult male albino rats with average weight 150-200 gm were used in this study. The animals were divided into 5 groups. Twelve rats were sham-operated and served as control group [group I]. The remaining 28 rats underwent right UA and were sacrificed after 3 days, 1, 2, 3 weeks [groups II, III, IV, and V respectively]. At the planned times, the left adrenal glands were excised and specimens were prepared for light and electron microscopic studies. Morphometric study was done to measure the thickness and the surface area of the cells of the three classical zones of the adrenal cortex. The results showed frequent mitotic figures in the outer zone of zona fasciculata in group II which was not evident in all other groups. In group III, the thickness and the surface area of the cells of zona fasciculata showed highly significant increase. The cells of zona glomerulosa and fasciculata showed marked cytoplasmic vacuolation more in zona fasciculata. Group IV showed gradual decrease in size and vacuolation of the cells which reverted to near normal in group V; three weeks after UA, denoting stabilization of the adrenal cortex. Electron microscopic examination revealed enlarged mitochondria, dilated smooth endoplasmic reticulum and decreased lipid content in group-III, while near normal appearance was achieved in group V. These results suggested that the compensatory growth in the adrenal cortex following UA was due to both hyperplasia and hypertrophy, and that zona fasciculata is the primary zone responsible for this compensatory growth