• Nutrition Research and Practice
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• v.7 no.1
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• pp.34-42
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• 2013

This study investigated the effects of magnetized water supplementation on blood glucose, DNA damage, antioxidant status, and lipid profiles in streptozotocin (STZ)-induced diabetic rats. There were three groups of 4-week-old male Sprague-Dawley rats used in the study: control group (normal control group without diabetes); diabetes group (STZ-induced diabetes control); and magnetized water group (magnetized water supplemented after the induction of diabetes using STZ). Before initiating the study, diabetes was confirmed by measuring fasting blood glucose (FBS > 200 dl), and the magnetized water group received magnetized water for 8 weeks instead of general water. After 8 weeks, rats were sacrificed to measure the fasting blood glucose, insulin concentration, glycated hemoglobin level, degree of DNA damage, antioxidant status, and lipid profiles. From the fourth week of magnetized water supplementation, blood glucose was decreased in the magnetized water group compared to the diabetes group, and such effect continued to the 8th week. The glycated hemoglobin content in the blood was increased in the diabetes group compared to the control group, but decreased significantly in the magnetized water group. However, decreased plasma insulin level due to induced diabetes was not increased by magnetized water supplementation. Increased blood and liver DNA damages in diabetes rats did significantly decrease after the administration of magnetized water. In addition, antioxidant enzyme activities and plasma lipid profiles were not different among the three groups. In conclusion, the supplementation of magnetized water not only decreased the blood glucose and glycated hemoglobin levels but also reduced blood and liver DNA damages in STZ-induced diabetic rats. From the above results, it is suggested that the long-term intake of the magnetized water over 8 weeks may be beneficial in both prevention and treatment of complications in diabetic patients.

• Journal of Periodontal and Implant Science
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• v.47 no.5
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• pp.339-350
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• 2017

Purpose: The purpose of this study was to determine the critical diabetes duration in a streptozotocin (STZ)-induced diabetic rat calvarial defect model for experimentation regarding bone regeneration by evaluating the association between diabetes duration and bone healing capacity through histological and radiographic analyses. Methods: Experimental diabetes was induced in 50 of 60 rats by an STZ injection. The rats were divided into 5 groups, including a control group (group 1), according to diabetes durations of 0, 2, 4, 6, and 8 weeks, respectively. Eighteen rats survived: 4 in group 1, 4 in group 2, 4 in group 3, 5 in group 4, and 1 in group 5. Calvarial defects were created at 0, 2, 4, 6, and 8 weeks after STZ injection in groups 1-5. Cone-beam computed tomography scanning was performed at baseline and at 5 and 7 weeks after surgery. The rats were sacrificed 7 weeks after surgery, followed by histological evaluation. Results: The voxel gray values (VGVs) of group 1 and group 2 increased, whereas the VGVs of group 3 and group 4 decreased starting 5 weeks after surgery, although this trend did not reach statistical significance between groups. On the reconstructed 3-dimensional images and based on an analysis of histological features, groups 1 and 2 showed apparent bone regeneration, while groups 3-5 showed very limited bone regeneration. Conclusions: The critical diabetes duration in an STZ-induced diabetic rat calvarial defect model for experimentation regarding bone regeneration was between 2 and 4 weeks. It is suggested that researchers who use STZ-induced diabetic rats wait for more than 2 weeks following diabetes induction before placing implants or conducting bone regeneration studies to allow definite disturbances in bone healing to emerge.

• Journal of Life Science
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• v.21 no.3
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• pp.435-443
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• 2011

The purpose of this study is to identify the effects of exercise training [ET, 10~18 m/min (speed), 20~30 min (exercise duration)/a day for 5 day/wk, 6 wk) on PGC-$1{\alpha}$, GLUT-1, Tfam, Cu,Zn-SOD and Mn-SOD proteins in brain of STZ-induced diabetic rats. The male Sprague-Dawley (SD) rats were single-injected intraperitoneally with 50mg/kg of streptozotocin (STZ) to produce STZ-induced diabetic rats. Rats were divided into 3 experimental groups with 8 rats in each group, as follows: (1) non-STZ group (n=8), (2) STZ-CON group (n=8), (3) STZ-EXE group (n=8). The results of this study suggest that i) serum glucose level was significantly reduced in STZ-EXE group compared with STZ-CON group (p<0.05), ii) PGC-$1{\alpha}$ (p<0.001), mtPGC-$1{\alpha}$ (p<0.001), GLUT-1 (p<0.001), and mtTfam (p<0.001) proteins in brain of STZ-induced diabetic rats were significantly increased in STZ-EXE group compared with STZ-CON group, iii) Cu,Zn-SOD (p<0.001) and Mn-SOD (p<0.01) proteins in the STZ-induced diabetic rats were significantly increased in STZ-EXE group compared with STZ-CON group. In conclusion, the findings of the present study reveal that treadmill exercise training increases brain GLUT-1 protein level possibly through up-regulation of PGC-$1{\alpha}$ and Tfam proteins which represent key regulatory components of stimulation of brain mitochondrial biogenesis. In addition, treadmill exercise training may prevent oxidative stress by up-regulation of Cu,Zn-SOD and Mn-SOD proteins in the STZ-induced diabetic rats.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.1
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• pp.39-45
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• 2003

Reactive oxygen species (ROS) have been suggested to be contributory factors in complications of diabetes mellitus. In the present study, we investigated the generation of superoxide, the lipid peroxide level measured as thiobarbituric acid reactive substances, the vasorelaxation of isolated thoracic aorta and the iNOS expression in kidney of streptozotocin induced diabetic rats. Sprague Dawley rats were divided into four groups: control, ascorbate (400 mg/kg rat weight daily in drinking water), diabetic (single dose of 50 mg of STZ/kg i.p.) and diabetic simultaneously fed with ascorbate for 12 wk. Rats in groups were studied at tri-weekly intervals (0 to 12 wk). Diabetic rats were evaluated periodically with changes of plasma glucose levels and body weight. The ascorbate supplimentation attenuated the development of hyperglycemia and weight loss induced by STZ injection in rats. In the present experimental condition, the ascorbate supplimentation had no significant effect on plasma glucose levels and changes in body weight of normal rate. The superoxide generation, formation of thiobarbituric acid reactive substance and iNOS expression in kidney were significantly increased in STZ-treated rats that were decreased by ascorbate supplimentation. The ascorbate supplimentation had no effect on vasorelaxation of isolated thoracic aorta. These results indicate that ascorbate supplimentation may exert an inhibitory effect on STZ-induced oxidative tissue damage through protection of pancreatic islet cells by scavanging reactive oxygen species. The ascorbate supplimentation may possibly attenuate the renal complication of diabetes mellitus.

• Journal of the Korean Applied Science and Technology
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• v.32 no.2
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• pp.226-231
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• 2015

This study was carried to investigate the antidiabetic effect of ethanol extract in Streptozotocin(STZ)-induced diabetic rats. Diabetes was induced by intravenous injection of STZ at a dose of 45mg/kg dissolved in citrate buffer. The ethanol extract of Forsythia Koreana(F.K) was orally administrated once a day for 7 days at a dose of 1,000mg/kg. The contents of serum glucose, triglyceride(TG), total cholesterol were significantly decreased in F.K treated group compared to the those of STZ-control group. The content of hepatic glycogen and activity of glucokinase(GK) were significantly increased, and activity of glucose-6-phoshatase(G-6-Pase) was significantly decreased in F.K treated group compared to the those of STZ-control group, but activity of glucose-6-phosphate dehydrogenase(G-6-PDH) was not significantly increased, These results indicated that ethanol extract of F.K would have antidiabetic effect in STZ-induced diabetic rats.

• Journal of Life Science
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• v.14 no.2
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• pp.245-251
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• 2004

Exercise is beneficial to the diabetic patients and streptozotocin-induced diabetic rat has been used for the study of exercise effect. The purpose of this study was to establish the optimal condition of induction of hyperglycemic diabetic rat using streptozotocin and to examine the preventive effect of treadmill exercise on the diabetic rat before and after streptozotocin injection. Intraperitoneal injection of increasing amount of streptozotocin up to 40 mg/kg dose-responsively induce hyperglycemic diabetic rat and inversely reduced the blood insulin level. Body weight was also gradually reduced with the increasing amount of streptozotocin. Control and diabetic rats exercised for 4 weeks before streptozotocin injection. The exercise was performed in the treadmill for 25 minutes a day and 5 times a week with low intensity (0 degree tilt, 15 m/min velocity). Following streptozotocin injection, the blood glucose level was measured every week and the rat was sacrificed after 4 weeks to measure the concentration of insulin and blood lipids. The blood levels of glucose and insulin was significantly reduced with exercise before streptozotocin injection, while those were not changed after streptozotocin injection. The levels of blood lipids such as total cholesterol, HDL-cholesterol, LDL-cholesterol and triglyceride were close to normal control rats. From this study, researchers found the optimal condition of preparation of streptozotocin-induced hyperglycemic diabetic rat, and the mild treadmill exercise has beneficial effect on preventing hyperglycemia and hyperlipidemia. Thus, even low intensive running prevent not only diabetes but also diabetic vascular complications.

• Nutritional Sciences
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• v.9 no.2
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• pp.97-105
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• 2006

Beans are well known to be high-protein diets. Bean seeds contain arginine, lysine, or glycine-rich proteins which are effective to maintain lower glucose levels. In this study, the synergistic effect of fermented small soybean (Chounggukjang) and mulberry leaf on metabolism and hexokinase activity was investigated in streptozotocin (STZ)-induced diabetic rats. We divided 8 groups as follows: non-diabetic rat group fed with only water diet (NC: control), and STZ-induced diabetic rat groups fed with water (DC), fermented Rhynchosia Nulubilis (Bbc), fermented Glycine max Merr (Ybc), Bbc and YBc (BYbc), mulberry leaf and Bbc (MBbc), mulberry leaf and Ybc (MYbc), or the mulberry leaf, Bbc, and Ybc (MBYbc). Diabetes mellitus was induced in rats by subcutaneous STZ administration (70 mg/kg of body weight). All diet groups were fed with Chounggukjang in a powder form. Three ml of Chounggukjang solution (0.75 mg per gram of body weight) dissolved in distilled water was orally administered to all rat groups after STZ administration except for NC rat group. In groups fed with fermented soybeans, the body weight (increased), food efficiency ratio (FER) (increased), glucose level (decreased) and hexokinase (HK) activity (increased) significantly differed to NC. Among them, particularly in the groups fed with both fermented soybeans and mulberry leaf, kidney weight significantly decreased, whereas HK activity significantly increased compared to DC. These results suggest that Chounggukjang of both fermented soybeans and mulberry leaf is potentially used as an effective functional food to prevent diabetes complications.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.3
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• pp.663-669
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• 1999

The purpose of this study was to investigate the effects of vitamin E on the histochemical change of kidney tissue in diabetic rats. Sprague Dawley male rats weighing 100$\pm$10g were randomly assigned to one normal and three STZ induced diabetic groups, which were subdivided into vitamin E free diet(DM 0E group), 40mg vitamin E per kg diet(DM 40E group) and 400mg vitamin E per kg diet(DM 400E group). Vitamin E level of normal group was 40mg per kg diet. Diabetes was exper imentally induced by intravenous injection of 55mg/kg of body weight of streptozotocin(STZ) in citrate buffer(pH 4.3) after 4 weeks feeding of experimental diets. Animals were sacrificed at the 6th day of diabetic states. The contents of thiobarbituric acid(TBARS) in kidney were increased 119%, 84% and 33% in DM 0E, DM 40E and DM 400E groups, respectively, compared to normal group. That of DM 400E group was decreased 39% compared to DM 0E group. Content of 2 microglobulin in urine in DM 0E, DM 40E, and DM 400E groups were increased by 248%, 181%, and 164%, respectively, compared to normal group. The diabetic groups showed the regressive lesion such as renal tubule, intumescence of epithelial cell, vacuolization. The results of the observation through electronic microscope showed the mitochondria shape of proximal tubule epithelial cell, irregular array, increase of ribosome, and irregular arrangement of small villosity, etc. These types of changes appeared severer in DM 0E group than in DM 400E group. These results indicate that the TBARS productions on kdney in STZ induced diabetic rats were increased, consequently those leaded to damage of renal tubule and minuteness structure. But a large quantity vitimin E supplementation was suppressed in TBARS production and improved in peroxidative damage of renal tissue so that relieved degenerative changes of renal tubule epithelial cell.

• Journal of Life Science
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• v.12 no.1
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• pp.1-7
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• 2002

The purpose of this study was designed to observe the effects of the feeding Zizyphus jujuba seed extract on the improvement of the blood glucose, lipids in the serum of streptozotocin (STZ)-induced diabetic rats fed the experimental diets for 4 weeks. Concentrations of blood glucose, total cholesterol, atherosclerotic index, LDL, LDL-cholesterol, free-cholesterol, cholesteryl ester, triglyceride (TG) and phospholipid (PL) in serum were significantly higher in the STZ (55mg/kg B.W.)-induced diabetic group (group 2) and STZ (I.P.)+ Zizyphus jujuba seed extract group (group 3) than those in the control group (group 1, basal diet + water). But the concentrations of blood glucose, total cholesterol, atherosclerotic index, LDL, LDL-cholesterol, free-cholesterol, cholesteryl ester, TG and PL in serum were remakably lower in the group 3 than those in the group 2. In the ratio of HDL-cholesterol concentration to total cholesterol and HDL-cholesterol concentration, Zizyphus jujuba seed extract administration group (group 3) were higher percentage than in the group 2. The activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) in serum were rather lower in the Zizyphus jujuba seed extract administration group (group 3) than in the STZ- induced diabetic group (group 2). From the above results, it was suggested that the Zizyphus jujuba seed were effective on the improvement of the blood glucose, lipid compositions in serum of STZ-induced diabetic rats. Moreover, in Zizyphus jujuba seed was effective therapeutic regimen for the control of metabolic derangements in adult disease.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.1
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• pp.45-53
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• 1997

In humans and many animal models with chronic progressive renal diseases, angiotensin-converting enzyme (ACE) inhibitor markedly attenuates the progression of nephropathy. Several studies have reported augmented gene expression and redistribution of renal renin in partial nephrectomized rats. Although precise mechanism(s) is not known, the renin-angiotensin system (RAS) may play an important role in the progression of renal diseases. Thus, this study was undertaken to examine the gene expression of renal renin, angiotensinogen, and $AT_1$ subtypes ($AT_{1A}$ and $AT_{1B}$) in rats with diabetic nephropathy, and the influences of lipopolysaccharide (LPS)-induced septicemia on the gene expression. Four weeks after streptozotocin (STZ) treatment (55 mg/kg, i.p.), rats were randomly divided into LPS-treated (1.6 mg/kg, i.p.) and control rats. At 6 hours after LPS treatment, the rats were killed and the kidney was removed from each rat. Northern blot and reverse transcription-polymerase chain reaction (RT-PCR)techniques were used to detect mRNA expression. STZ treatment markedly attenuated body weight gain and significantly increased blood glucose level. Renal renin content (RRC) was significantly decreased in the STZ-treated rats compared to that in control rats. The renal ACE activity between STZ-treated and control rats was not significantly different. Renal renin mRNA level was prominently increased, while angiotensinogen and $AT_{1A}$ mRNA levels were slightly decreased in STZ-treated rats compared to those in controls. $AT_1$B mRNA level did not differ in both groups. Acute LPS treatment did not show any significant changes of mRNA levels of intrarenal RAS components in both groups. These results suggest that intrarenal RAS components were differentially regulated in STZ-treated diabetic rats. Further studies are required to evaluate the relationship between intrarenal RAS and other vasomodulatory systems.