Our objective was to study the effects of three (30, 40, and 50 mg/kg) doses of Streptozotocin (STZ) on fasting plasma glucose level (FPG) and observe its effects at the cellular level in rat pancreas by electron microscopy. FPG was measured in rats before induction of diabetes and then on 3, 7, and 14 days after induction of diabetes with STZ. Keto diastix urine strips were used to check urine glucose and ketone bodies. Two weeks after the induction of diabetes, the rat pancreas was removed and fixed for light and electron microscopic studies. Three days after induction, the mean FPG level was 112 mg/dl in Group I (30 mg/kg STZ), 217 mg/dl in Group II (40 mg/kg STZ), and 376 mg/dl in Group III (50 mg/kg STZ). Histology was normal in Group I but revealed altered islet structure in Groups II and III. Ultrastructure revealed intact D cells in all three groups. The focal mitochondria and Golgi complex swelling found in A and B cells was occasional in Group I and frequent in Groups II and III. Swelling of other organelles and reduction in the size and number of granules was further observed in Group III. It is our conclusion that the 30-mg/kg body weight STZ produces mild changes while 50 mg/kg proves to be fatal. STZ at 40 mg/kg has a moderate effect on plasma glucose as well as on the islets of Langerhans at a cellular level.

Background:Diabetes mellitus is a metabolic disorder characterized by chronic hyperglycemia. Plant extracts and their products are being used as an alternative system of medicine for the treatment of diabetes. Aloe vera has been traditionally used to treat several diseases and it exhibits antioxidant, anti-inflammatory, and wound-healing effects. Streptozotocin (STZ)-induced Wistar diabetic rats were used in this study to understand the potential protective effect of A. vera extract on the pancreatic islets.Objective:The aim of the present study was to evaluate the A. vera extract on improvement of insulin secretion and pancreatic β-cell function by morphometric analysis of pancreatic islets in STZ-induced diabetic Wistar rats.Materials and Methods:After acclimatization, male Wistar rats, maintained as per the Committee for the Purpose of Control and Supervision of Experiments on Animals guidelines, were randomly divided into four groups of six rats each. Fasting plasma glucose and insulin levels were assessed. The effect of A. vera extract in STZ-induced diabetic rats on the pancreatic islets by morphometric analysis was evaluated.Results:Oral administration of A. vera extract (300 mg/kg) daily to diabetic rats for 3 weeks showed restoration of blood glucose levels to normal levels with a concomitant increase in insulin levels upon feeding with A. vera extract in STZ-induced diabetic rats. Morphometric analysis of pancreatic sections revealed quantitative and qualitative gain in terms of number, diameter, volume, and area of the pancreatic islets of diabetic rats treated with A. vera extract when compared to the untreated diabetic rats.Conclusion:A. vera extract exerts antidiabetic effects by improving insulin secretion and pancreatic β-cell function by restoring pancreatic islet mass in STZ-induced diabetic Wistar rats.SUMMARY Fasting plasma glucose (FPG) and insulin levels were restored to normal levels in diabetic rats treated with Aloe vera extractIslets of pancreas were qualitatively and quantitatively restored to normalcy leading to restoration of FPG and insulin levels of diabetic rats treated with Aloe vera extractMorphometric analysis of pancreatic sections revealed quantitative and qualitative gain in terms of number, diameter, volume, and area of the pancreatic islets of diabetic rats treated with Aloe vera extract when compared to the untreated diabetic rats. Abbreviations Used: A. vera, FPG: Fasting plasma glucose, STZ: Streptozotocin, BW: Body weight

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The aim of this study was to assess recovery, cell death, and cell composition of post-thaw cultured human islets. Cryopreserved islets were provided by the Clinical Islet Transplant Program, Edmonton, Canada. Islets were processed using media prepared in accordance with Pre-Edmonton and Edmonton protocols. Cryopreserved islets were rapidly thawed and cultured for 24 h, 3 d, 5 d, and 7 d, following which they were processed for histology. Islet quantification, integrity, morphology and tissue turnover were studied via hematoxylin and eosin stained sections. Ultrastructure was studied by electron microscopy and endocrine cell composition by immunohistochemistry. Using the Pre-Edmonton protocol, islet recovery was 50.1% and islet survival was 50% at 24 h while for the Edmonton protocol, the islet recovery was 69.4% (p<0.001) and islet survival, 50% at ≈2.5 d. With an increasing culture duration although the physical integrity was retained there was an increasing loss of cohesivity both at light microscopic and at ultrastructure level regardless of the protocols used. Percentage islet survival and tissue turnover correlated negatively with culture duration in both protocols. The Edmonton protocol appears to preserve the islets better. However, culture duration adversely affects islet survival and quality, indicating the need for more optimal cryopreservation and culture techniques.

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