Role of thyroxin versus Brewer's yeast supplementation in amelioration of pancreatic alterations induced by hypothyroidism in adult male albino rats

Induction of hypothyroidism by carbimazole could affect many glands including the pancreas. Brewer's yeast, a herbal product, is recently under research for its possible uses. The aim of the study was to study the microscopic, morphometric, and biochemical changes in the pancreas of hypothyroid rats and to evaluate the role of thyroxin versus Brewer's yeast in amelioration of these changes. Sixty adult male albino rats were randomly divided into five groups. Group I rats served as a control group. Group II rats received carbimazole. Group III rats received carbimazole followed by thyroxin. Group IV rats received carbimazole followed by Brewer's yeast. Group V rats received only Brewer's yeast. At the end of the experimental period, specimens from the pancreas were processed for light and transmission electron microscopic examinations and immunostaining for Ki-67. Biochemical analysis for T3, T4, and insulin was performed. In addition, body mass gain and pancreatic mass were measured. All parameters were statistically analyzed. Group II specimens revealed congestion of blood vessels and cellular infiltration. Acinar cells showed pyknotic nuclei, hyalinization, and vacuolation of the cytoplasm, with few zymogen granules. beta Cells of the islets of Langerhans revealed depletion of organelles and small granules without their characteristic halo. Immunostaining revealed significant decrease in the percentage of Ki-67-positive nuclei. In group III, the acini revealed numerous secretory granules, few vacuoles, and euchromatic nuclei. beta Cells showed secretory granules with the characteristic halo. Group IV revealed less improvement in the histopathological changes as compared with group III. T3, T4, and insulin levels were significantly lower in hypothyroid rats in comparison with the control group, whereas administration of thyroxin showed restoration of these levels to near control values. Hypothyroidism showed a deleterious effect on the histological structure of rat's pancreas. Administration of thyroxin minimized these effects more than administration of Brewer's yeast

Light and electron microscopic study on the protective role of corneal epithelium against the effect of "UVB" radiation on rabbit cornea

The human eye might be subjected to repeated exposure to ultraviolet radiation [UVR] either during a single day or over a longer period of time. It is known that the cortical epithelium strongly absorbs UVR. The aim of this study was to evaluate the protective role of corneal epithelium against the effect of UVB radiation on corneas of albino rabbits in comparison with that on de-epithelialized corneas. Sixteen adult female New Zealand albino rabbits [3-3.5 Kg] were divided into 4 groups, 4 rabbits each. Group I served as control. Group II served also as control, but their corneas underwent manual de-. In group III, corneas were exposed to UVB irradiation, peaked at 3l2nm as a single dose [3.12J/cm2] for 30 minutes. In group IV corneas underwent manual de-epithelialization. 5 minutes prior to UVB exposure. All animals were sacrificed after 48 hours, and the corneas were removed and processed for histological and transmission electron microscopic study. The histological results of group III revealed that the corneas had slight edema and the keratocytes in the outer stroma appeared to be affected. Ultrastructural evaluation of this group showed affected epithelial cells and the keratocytes revealed early apoptotic changes like chromatin condensation. Results of group IV showed that the stromal damage was deeper and more extensive. The keratocytes had been markedly affected in the entire thickness and there was thinning out of Descemet's membrane. Ultrastructurally, the keratocytes showed chromatin condensation, fragmentation and cell shrinkage. Disorganized collagen lamellae were also seen. It was concluded that the removal of the corneal epithelium makes the underlying ocular structures-more susceptible to damage by UVB in the 312nm range. Further studies are needed to investigate whether the corneal epithelium has protective properties against UVB at other wavelengths