• Imaging Science in Dentistry
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• v.33 no.3
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• pp.161-169
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• 2003

Purpose: To observe the histologic changes and clusterin expression in the acinar cells of the submandibular gland in streptozotocin-induced diabetic rat following irradiation. Materials and Methods: Mature Sprague-Dawley rats were divided into three groups: control, diabetic, and diabetic-irradiated groups. Diabetes mellitus was induced in the Sprague-Dawley rats by injecting streptozotocin, while the control rats were injected with citrate buffer only. After 5 days, rats in diabetic-irradiated group were irradiated with single absorbed dose of 10 Gy to the head and neck region. The rats were killed at 1, 3, 7, 14,21, and 28 days after irradiation. The specimen including the submandibular gland were sectioned and observed using histologic and immunohistochemical methods. Results : Morphologic change of acinar cells was remarkable in the diabetic group, but was not observed in the diabetic-irradiated group. Necrotic tissues were observed in the diabetic-irradiated group. Coloring of toluidine blue stain was most increased at 14 days in the diabetic group, however there were no significant change throughout the period of the experiment in the diabetic-irradiated group. Expression of clusterin was most significant at 14 days in the diabetic group, but gradually decreased with time after 7 days in the diabetic-irradiated group. Degeneration of clusterin was observed in the diabetic-irradiated group. Conclusion : This experiment suggests that the acinar cells of submandibular gland in rats are physiologically apoptosed by the induction of diabetes, but that the apoptosis is inhibited and the acinar cells necrotized after irradiation.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.3
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• pp.250-261
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• 2006

Diabetes mellitus, as a major health problem for the elderly, is associated with an extensive list of complications involving nearly every tissue in the body and has been shown to alter the properties of bone and impair fracture healing in both human and animals. The objective of this study was to examine the healing process of a mandibular fracture in the streptozotocin-induced rats histomorphometrically and histologically. A standardized fracture model was chosen and based on blood-glucose value at the time of surgery. A total of 11-weeks old 36 rats were divided into 2 groups; One is a streptozotocin-induced diabetic group and the other is a non-diabetic group. All was fractured experimentally. Three animals from each group were killed 1, 2, 4, 6, 8 and 12 weeks after fracture and specimens were processed undecalcified for quantitative bone histomorphometric and histologic studies. The diabetic group showed a significant decrease of histomorphometry-based parameter including trabecular bone volume, trabecular thickness in comparison to the non-diabetic rat. This was confirmed histologically. In conclusion, this study suggests that in streptozotocin-induced diabetics, the healing process of bone fracture was impaired and delayed about 2-3 weeks comparing to non-diabetics.

• Journal of Nutrition and Health
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• v.34 no.3
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• pp.253-264
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• 2001

This study was carried out to examine a part of the mechanism for the etiology of diabetic complications. Thirty normal and forty streptozotocin(STZ)-induced diabetic rats were used as the animal models. The animals were sacrificed at the time points of 3 days, 1,2,4 and 6 weeks after STZ-injection and a time course changes in the concentrations of thiobarbituric acid-reactive substances(TBARS) in blood, urine, and tissues, along with the levels of conjugated dienes in tissues were measured as indices of in vivo lipid peroxidation. The activities of antioxidant enzymes, catalase, superoxide dismutase, glutathione peroxidase and the levels of blood retinol and alpha-tocopherol were also measured. The diabetic rats maintained a slightly higher plasma TBARS level throughout the experiment. The urinary TBARS level was significantly higher in diabetic group and gradually increased with time. Concentrations of TBARS in liver, heart, and kidney tissues from diabetic animals were higher than those from the normal group. An increase of conjugated dienes was also observed in the all tissues examined. The kidney tissue of diabetic animals revealed more significant lipid peroxidation state than any other organ tissues. The activities of hepatic antioxidant enzymes such as catalase, superoxide dismutase, glutathione peroxidase were higher in diabetic animals compared to the control ones and increased with the duration of diabetes mellitus. The plasma levels of vitamin A and E were loser in diabetic animals than in normal controls throughout the experimental period. The level of vitamin E in diabetic animals was significantly decreased with the duration of the disease. The results of this study suggest that an effective regimen to suppress the adverse changes in lipid peroxidation and antioxidant defense system is required from the early stage of the disease to prevent the development of diabetic complications. (Korean J Nutrition 34(3) : 253∼264, 2001)

• The Korean Journal of Mycology
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• v.44 no.1
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• pp.57-60
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• 2016

Following preparation of water extracts of Pleurotus cornucopiae fruiting body-containing ${\alpha}$-glucosidase inhibitor, their antihyperglycemic effects were examined using streptozotocin-induced diabetic Sprague-Dawley (SD)-rats. The water extracts from Pleurotus cornucopiae showed dosage-dependant antihyperglycemic effects on the streptozotocin-induced diabetic SD-rats after oral administration to 120 min on the short time test and 4 days on the long time test, respectively. The water extracts from Pleurotus cornucopiae fruiting body showed dosage-dependent hypoglycemic action after administration to 120 min and 4 days in the SD-rat and streptozotocin-induced diabetic SD-rat.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.4
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• pp.475-482
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• 2015

This study was conducted to examine whether or not oligonol, a low molecular weight polyphenol derived from lychee fruit, has an ameliorative effect on diabetes-induced oxidative stress-related hepatic damage in streptozotocin (STZ)-induced diabetic rats. Oligonol (10 or 20 mg/kg body weight; O10 or O20, respectively) was orally administered every day for 10 days to STZ-induced diabetic rats, and its effects were compared to vehicle-treated diabetic (Veh) and non-diabetic rats. Administration of 20 mg/kg of oligonol significantly decreased liver weight compared with the Veh group (P<0.05). Elevated levels of hepatic glucose, reactive oxygen species, peroxynitrite, and lipid peroxidation were detected in diabetic vehicle rats, whereas oligonol treatment significantly attenuated these levels (P<0.05). In diabetic vehicle rats, hepatic antioxidant enzyme protein levels decreased, whereas oligonol treatment showed significant elevated results. For inflammation-related protein expression, oligonol-treated groups showed insignificant reduction. Oligonol improved expression of proapoptotic protein caspase-3 in the liver of diabetic rats (P<0.05). In conclusion, these results provide important evidence that oligonol exhibits an inhibitory effect on oxidative stress and apoptosis-related protein expression as well as a hepato-protective effect against the development of diabetic complications in STZ-induced type 1 diabetic rats.

• Journal of the East Asian Society of Dietary Life
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• v.15 no.2
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• pp.158-164
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• 2005

The present study was undertaken to evaluate the effect of Rhodiola sachalinensis root ethanol extract (RS), on the body weight, organ weight, plasma glucose and plasma lipid in diabetic rats caused by streptozotocin (STZ). The body weight decreased more slowly in the RS group than in the diabetic, and the food intake increased significantly in all diabetic groups. The food efficiency was very low in all diabetic groups, but increased significantly in the RS groups than diabetic control (p<0.05). In comparing the weight of organ, the weight of liver and kidney were increased in all diabetic groups than in the control, and decreased slightly in RS groups. The weight of heart and spleen were not different among all test groups. The glucose in serum was decreased significantly in the RS groups fed the RS for 4 weeks, compared to the diabetic control (p<0.05). Total cholesterol, triglyceride and atherogenic index (AI) in serum were significantly higher in diabetic control, compared to the normal (p<0.05), and decreased $16.7\%,\;18.3\%\;and\;45.0\%$, respectively, in the RS fed $300\;\cal{mg/kg}$ of RS. HDL-cholesterol was increased slightly more in the $RS-300\;\cal{mg/kg}$, compared to diabetic control. These findings suggest that RS treatment has protective effect in diabetes.

• Korean Journal of Pharmacognosy
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• v.33 no.1 s.128
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• pp.21-28
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• 2002

Antidiabetic effects of the acid hydrolysate of silk fibroin were investigated by oral administration to animal models for diabetes mellitus, Fibroin protein was extracted from cocoon and digested to peptides of low-molecular weight range (mainly below 3,000) and amino acids by acid hydrolysis, Feeding of the fibroin hydrolysate resulted in a significant recovering effect on reduction of body weight gain and a lowering effect on blood glucose gain in streptozotocin-induced diabetic Sprague Dawley rats (STZ rats) which were used as an insulin-dependent diabetic animal model. But the body weight and blood glucose level in C57BL/KsJ-db/db mice (db/db mice), an non-insulin-dependent diabetic animal model, were not changed significantly by the feeding, On the other hand, plasma leptin levels increased according to increased feeding amount of the hydrolysate in STZ rats and db/db mice in common, It was concluded from the results that the fibroin hydrolysate might stimulate the insulin secretion by recovering or activating pancreatic ${\beta}$ cells and result in the increased plasma leptin level. It was also deduced that the antidiabetic improvements in body weight and blood glucose gain in STZ were thought to be due to the increased insulin secretion, but in db/db mice of which the diabetic symptoms were caused by insulin resistance, the stimulated secretion of insulin was unlikely to be able to change body weight and blood glucose level significantly.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.4
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• pp.375-382
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• 1999

Growing evidence indicates that enhanced generation or actions of nitric oxide (NO) are implicated in the pathogenesis of hypertension in spontaneously hypertensive rats and diabetic nephropathy in streptozotocin (STZ)-induced diabetic rats. We investigated whether inducible nitric oxide synthase (iNOS) expression in STZ-induced diabetic rats is responsible for the alterations of vascular reactivity. Diabetic state was confirmed 28 days after injection of STZ (i.p) in rats by measuring blood glucose. In order to evaluate whether short term (4 weeks) diabetic state is related with altered vascular reactivity caused by iNOS expression, isometric tension experiments were performed. In addition, plasma nitrite/nitrate (NOx) levels and expression of iNOS in the lung and aorta of control and STZ-treated rats were compared by using Griess reagent and Western analysis, respectively. Results indicated that STZ-treated rats increased the maximal contractile response of the aorta to phenylephrine (PE), and high $K^+,$ while the sensitivity remained unaltered. Endothelium-dependent relaxation, but not SNP-mediated relaxation, was reduced in STZ-treated rats. Plasma nitrite/nitrates are significantly increased in STZ-treated rats compared to controls. The malondialdehyde (MDA) contents of liver, serum, and aorta of diabetic rats were also significantly increased. Furthermore, nitrotyrosine, a specific foot print of peroxynitrite, was significantly increased in endothelial cells and smooth muscle layers in STZ-induced diabetic aorta. Taken together, the present findings indicate that enhanced release of NO by iNOS along with increased lipid peroxidation in diabetic conditions may be responsible, at least in part, for the augmented contractility, possibly through the modification of endothelial integrity or ecNOS activity of endothelium in STZ-diabetic rat aorta.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.7
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• pp.3310-3316
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• 2011

Hematoxylin is the main component of Hematoxylon campechianum which has been utilized in the southern provinces of Korea as a folk remedy for diabetic complications. In the present study, to investigate the hypoglycemic mechanism of hematoxylin, the 2-deoxyglucose uptake and phospholipid metabolism were examined in sciatic nerves from three groups of rats : normal control, diabetic control, diabetic hematoxylin-treated group. Hematoxylin significantly reduced blood glucose levels in diabetic control rats. On a wet weight basis, the nerves from diabetic rats showed a 20% decrease in total phospholipid from that of controls and a relative decrease in phosphatidylinositide. Hematoxylin treatment increased the incorporation rate of 2-[3H] myo-inositol into total phosphoinositids in diabetic rat. The effectiveness were more potent in higher dose hematoxylin-treated rats than lower dose hematoxylin-treated rats. These results suggest that hematoxylin increases glucose transport and lipid metabolism by partially normalizing concerned with myo-inositol metabolism in diabetic rat. Therefore we propose that hematoxylin can be a promising candidate for diabetes medication.

• Nutrition Research and Practice
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• v.1 no.4
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• pp.266-272
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• 2007

The present study evaluated the effect of various dosages of soybean isoflavone extract on body weight changes, glucose tolerance and liver function in streptozotocin-induced diabetic rats. One group of normal rats (normal control) was fed an AIN-76-based experimental diet and four groups of diabetic rats were fed the same diet supplemented with four different levels of soybean isoflavone extract for seven weeks. The daily dosages of pure isoflavone for four diabetic groups were set to be 0 mg (diabetic control), 0.5 mg (ISO-I), 3.0 mg (ISO-II) and 30.0 mg (ISO-III) per kilogram of body weight, respectively. The daily consumption of isoflavone at the level of 3.0mg per kilogram of body weight resulted in the suppression of body weight loss and increased the survival rate of diabetic animals one and half times compared to that of the diabetic control group. Blood glucose levels in a fasting state and after the oral administration of glucose were significantly lower in the ISO-II group during the oral glucose tolerance test. The ISO-II group showed a tendency to elongate the gastrointestinal transit time. The activity of serum aminotransferases, indicator of liver function, was not negatively affected by any intake level of isoflavone. The present study demonstrated that the soybean isoflavone extract may be beneficial to diabetic animals by improving their glucose tolerance and suppressing weight loss without incurring hepatotoxicity at the daily dosage of 3.0 mg per kg of body weight.