Effects of Mulberry Juice and Cake powders on Blood Glucose and Lipid Lowering and Erythrocytic Antioxidative Enzyme Activities in Streptozotocin -Induced Diabetic Rats

The aim of this study was to investigate the effects of mulberry juice and cake powder on blood glucose and lipid status along with intestinal disaccharidase and erythrocyte antioxidative enzyme system in streptozotocin (STZ )-induced diabetic rats. Sprague-Dawley male rats weighing 100 +/- 10 g were randomly assigned to one normal group, and eight STZ-induced diabetic groups: control diet group without mulberry juice and cake powders (DM-C ), three mulberry juice powder groups (0.5%:DM-0.5J, 1%:DM-1J, 2%:DM-2J )and four mulberry cake powder groups (0.25%:DM-0.25C, 0.5%:DM-0.5C, 1%:DM-1C, 2%:DM-2C ). After three-week feeding of each experimental diet, diabetes was induced by intravenous injection of 50 mg/kg body weight of STZ in sodium citrate buffer (pH 4.3 )via tail vein of eight DM groups. Rats were sacrificed at the 9th day of diabetic states. Level of blood glucose was 505 mg/dl in DM-C group but it was 28% and 39% lower in mulberry juice and cake powder fed groups, respectively, than the DM-C group. Activities of maltase, sucrase and lactase in proximal part of small intestine were significantly lower in the mulberry juice and cake powder groups by 42~47% than those of DM-C group. Erythrocytic superoxide dismutase, glutathione peroxidase and catalase activities were significantly reduced by STZ but increased close to normal levels along with less accumulation of thiobarbituric acid reactive substances (TBARS ). Serum levels of triglyceride and total cholesterol and HDL-cholesterol by STZ-DM were reduced and increased respectively, to the normal levels by the mulberry juice and cake powder. Except the levels of TBARS, the effects on the other measure-ments by the various dietary levels of mulberry juice and cake powder were almost same and the effect of the cake powder was most significant at the lowest level. These results indicate that mulberry juice and cake powders have considerable hypoglycemic effect and strengthening antioxidant defense systems at the low levels in diabetic state and may be able to reduce diabetic complications.

An Ultrastructural Study on the Early Morphologic Changes of the Retina in Streptozotocin-induced Diabetic Rats

There have been many theories for pathogenesis of diabetic retinopathy. However,no one theory can explain all of the pathogenesis. That means many factors contribute to the pathogenesis of the diabetic retinopathy. Many studies have shown the retinal changes in long-term hyperglycemia, yet relatively few in short-term hyperglycemia. To study the changes of the retinal capillary and retinal pigment epithelium in diabetic retinopathy, we measured the thickness of the basement membrane of the retinal capil-lary endothelial cells in streptozotocin-induced diabetic rats. An morphological alterations of the retinal pigment epithelium were also examined on the 2 month-old diabetic rats. The measurement was made using 0.1 mm calibrated ruler overlaying the electron micrograph with a transparent plastic sheet on which 20 radiating lines were etched exactly 18 .apart. The SPSS and Instat program were used for statistical evaluation of the data. Comparing with the control, the increase of the thickness of the endothelial basement membrane at the 2 month-old diabetic rats was statistically significant (p<0.05). Cytoplasmic alterations such as vacuolization of capillary endothelium, changes in mitochondria and increasement of capillary endothelialcytoplasm were more prominent in diabetic rats than in control rats. Basal infoldings of retinal pigment epithelium appeared to be more frequent and deeper in diabetic rats than in control rats.

Ultrastructural Changes of The Retinal Capillary Basement Membrane in The Streptozotocin-Induced Diabetic Rats

Ultrastructural changes of the retinal capillary basement membrane in the streptozotocin-induced diabetic rats Cho, Hokyun, M.D., Lee, Dohyung, M.D. We studied the changes of the retinal capillary in diabetic retinopathy. We measured the thickness of the basement membrane of the retinal capillary endothelial cells and the capillary pericytes using streptozotocin-induced diabetic rats and the results were compared with that of normal control rats. And also an morphological lterations of the retinal capillary were examed on the prediabetes and 3, 7 month-aged diabetic rats. The basement membrane thickness was measeured with 0.1mm calibrated ruler overlaying the electron micrograph with a transparent plastic sheet on which were etched 20 radiating lines exactly 18degree apart. The SPSS and Instat program were used for statistical evaluation of the data. An age related increase of the basement membrane of the capillary pericyte and endothelial cell was evident in both diabetic and control group. It was more prominent in the pericyte basement membrane of diabetic rats (diabetic rats 112.5%, control 62.5%). Comparing the age related thickening of the pericyte basement membrane and endothelial basement membrane, the increase of the thickness of the pericyte basement membrane at 7 month-aged diabetic rats was statistically significant(p<.0005). Some degenerative changes of the basement membrane itself and cytoplasmic degeneration of the endothelial cell and pericyte were visible, and those were more prominent in diabetic rats. Some capillary endothelial cell shows thinning in 7 month-aged diabetic rats.