ABSTRACT

This study was undertaken to investigate the protective effects of quercetin (QCT) on the morphology of pancreatic β-cells against diabetes mellitus and oxidative stress experimentally-induced by streptozotocin (STZ) treatment in Wistar rats. Fifty male and female Wistar rats (200-250 g) were randomly divided into three experimental groups (i. e., control, STZ-treated, and STZ + Quercetin-treated groups). Diabetes was induced in the diabetic groups (B and C) of animals, by a single intraperitoneal injection of STZ (75 mg/kg), while each of the rats in the 'control' group received equal volume of citrate buffer (pH 6.3) solution intraperitoneally. In group C rats, quercetin (QCT, 25 mg/kg/day i. p.) was injected daily for 3 days prior to STZ treatment, and QCT administration continued until the end of the study period (30 days). Diabetes mellitus was confirmed by using Bayer's Glucometer Elite ® and compatible blood glucose test strips. The rats were sacrificed serially until the end of the study period (after 30 days). The pancreases of the sacrificed rats were excised and randomly processed for histological staining and biochemical assays for antioxidant enzymes [such as glutathione peroxidase (GSHPx), superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA) and serum nitric oxide (NO)]. In the diabetic state, pancreatic β-cells of STZ-treated group B rats histologically demonstrated an early chromatin aggregation, cytoplasmic vesiculation in the central β-cells, nuclear shrinkage, and lysis of β-cells with distortion of granules. The morphology of QCT-treated rats' pancreases showed viable cellularity with distinct β-cell mass. STZ treatment significantly decreased (p<0.05) GSHPx, SOD, CAT and pancreatic insulin content. However, STZ treatment increased blood glucose concentrations, MDA and serum NO. The QCT-treated group of animals showed a significant decrease (p<0.05) in elevated blood glucose, MDA and NO. Furthermore, QCT treatment significantly increased (p<0.05) antioxidant enzymes' activities, as well as pancreatic insulin contents. Quercetin (QCT) treatment protected and preserved pancreatic β-cell architecture and integrity. In conclusion, the findings of the present experimental animal study indicate that QCT treatment has beneficial effects on pancreatic tissues subjected to STZ-induced oxidative stress by directly quenching lipid peroxides and indirectly enhancing production of endogenous antioxidants.

No abstract

The microarchitecture of the pangolin's stomach favouring the high chitinous diet has been less waived into, despite extensive morphological investigations. Histological analysis of the microanatomy will provide powerful tools for interpretation to yield reliable insights. We investigated this by fixing the tissues in 10% formol saline for histological analysis. Serial sections at 5 µ m thickness were subjected to general staining methods for light microscopic study (Haematoxylin and eosin, Van Gieson's and Verhoeff's). The results revealed basic structural arrangements in their coats, with a modification of the epithelial lining of cardia and fundus into stratified squamous keratinized epithelium. These modifications were also reflected in the distribution of collagen and elastic fibers in the various layers (coats) of the stomach. The present study has shown that there was an adaptation of the stomach of African tree pangolin to its diet as reflected in the microarchitectural configuration.

AKINOLA, O. B.; CAXTON-MARTINS, E. A. & DINI, L.Chronic treatment with ethanolic extract of the leaves of Azadirachta indica ameliorates lesions of pancreatic islets in Streptozotocin diabetes. Int. J. Morphol., 28(1):291-302, 2010. SUMMARY:Botanical drugs are complementary therapies in the management of diabetes mellitus. In this work, we studied the effects of chronic treatment of diabetic rats with A. indica (neem) on blood glucose, pancreatic islet histopathology, and oxidative status of the pancreas. Fifty-four Wistar rats (5-8 weeks old) were randomly assigned to 5 treatment groups. Hyperglycemia was induced in 34 fasted rats with a single i.p. injection of STZ (70 mg/kg bw/d). Ethanolic extract of A. indica leaves (500 mg/kg bw/d) was given orally to diabetic rats (n=12) for 50d. Glibenclamide was given (p.o) at 600 µg/ kg bw/d. In each group, blood glucose, islet histopathology, and pancreatic oxidative status, were assessed. All hyperglycemic rats in the neem-treated group had become normoglycemic at the end of week 2. By 50d, the number of viable b cells was highest in the neem-treated diabetic rats (compared with the diabetic and glibenclamide groups). Similarly, islet histology showed marked improvement in this group, in addition to improved oxidative stress. Our findings confirmed the hypoglycemic effect of neem. Besides, the improved islet morphology and oxidative status in neem-treated diabetic rats suggest the potential of this herb at improving lesions of the pancreatic islet in diabetes mellitus.