• Biomedical Science Letters
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• v.14 no.1
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• pp.19-26
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• 2008

This study investigated the effect of Rehmanniae Radix preparata extract on the antioxidant enzymes of kidney and renal function in streptozotocin-induced diabetic rats. Male Sprague-Dawley rats were divided into three groups including normal control (NC), diabetic control (DC), and diabetic treatment with Rehmanniae Radix preparata (DRR). Over a 4-week study period, Rehmanniae Radix preparata aqueous extract was administered orally at 1124 mg/kg BW/day. The serum glucose level in the DRR group was significantly lower (P<0.05) than the DC group. The serum blood urea nitrogen in diabetic groups was significantly higher (P<0.001) than the NC group. The urinary total protein level in the DRR group was significantly lower (P<0.05) than the DC group. The renal xanthine oxidase activity in the DRR group was significantly lower (P<0.01) than the DC group. The renal catalase activity in the DC group was significantly lower (P<0.05) compared to the NC group and that was significantly higher (P<0.05) in the DRR group than the DC group. In conclusion, these results indicated that Rehmanniae Radix preparata can prevent or retard the development of diabetic nephropathy via its beneficial effects for correcting the hyperglycemia and favorable effects on antioxidant enzyme system.

• 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 Acupuncture Research
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• v.26 no.6
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• pp.1-9
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• 2009

Objectives : For evaluation of preventive and anti-diabetic activities of Cinnamomi ramulus(CR) herbal acupuncture on pancreatic islet damage in streptozotocin(STZ)-induced diabetic rat. Methods : CR herbal acupuncture was performed at Bisu($BL_{20}$) for 3 weeks subcutaneously starting1 week before STZ i.p. injection. SD rats were divided into four groups(n=10 for each group); 1) NC group, non-treated normal control group, 2) STZ group, STZ administered control group, 3) CR125 group, CR(125mg/kg) + STZ administered group, and 4) CR250 group, CR(250mg/kg) + STZ administered group. Results : Both of CR250 and CR125 groups showed increase in insulin secretion and decrease in the level of serum triglyceride and non-esterified fatty acid in a dose-dependent manner compared to the STZ group. Only CR250 group showed decrease in the levels of glucose and total cholesterol compared to the STZ group. CR herbal acupuncture prevents $\beta$-cell damage of pancreatic islet, showing round figure on the sections of the pancreas. In the pancreatic cells, expressions of iNOS, JNK-2, P-JNK-1/2 and ERK-1/2 were decreased compared to the STZ group. CR herbal acupuncture solution did not show any cytotoxicity by MTS assay and inhibited expressions of iNOS and COX-2 in the STZ-induced diabetic rats. Conclusions : Therefore, we suggest that CR herbal acupuncture may act as a prophylactic as well as a therapeutic modality for diabetes mellitus.

• The Korea Journal of Herbology
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• v.23 no.2
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• pp.203-212
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• 2008

Objectives : This study was performed to prove the anti-hypertensive and anti-diabetic effect of Mori Ramulus(MR). Methods : The examination was done on the femoral artery occlusion of the rat, and check the blood pressure. In addition, we observed therapueutic effects on diabetes rats induced by streptozotocin. Results : MR MeOH Ex, showed few effect on descending blood pressure in SD rat model. MR CHC13 layer (MRC) showed significant effect on descending blood pressure. MR was effective on the streptozotocin-induced diabetes SD rats. Especially MRC reduced the amount of serum glucose, BUN, triglyceride and insulin level. Conclusions : MRC could induce descending blood pressure in the rat model. Also, it is expected to be effective in diabetes treatment.

• The Korean Journal of Physiology and Pharmacology
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• v.18 no.6
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• pp.461-467
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• 2014

The hypothesis of this study was that diabetes-induced desensitization of rat soleus (SOL) and extensor digitorum longus (EDL) to non-depolarizing muscle relaxants (NDMRs) depends on the stage of diabetes and on the kind of NDMRs. We tested the different magnitude of resistance to vecuronium, cisatracurium, and rocuronium at different stages of streptozotocin (STZ)-induced diabetes by the EDL sciatic nerve-muscle preparations, and the SOL sciatic nerve-muscle preparations from rats after 4 and 16 weeks of STZ treatment. The concentration-twitch tension curves were significantly shifted from those of the control group to the right in the diabetic groups. Concentration giving 50% of maximal inhibition ($IC_{50}$) was larger in the diabetic groups for all the NDMRs. For rocuronium and cisatracurium in both SOL and EDL, $IC_{50}$ was significantly larger in diabetic 16 weeks group than those in the diabetic 4 weeks group. For SOL/EDL, the $IC_{50}$ ratios were significantly largest in the diabetic 16 weeks group, second largest in the diabetic 4 weeks group, and smallest for the control group. Diabetes-induced desensitization to NDMRs depended on the stage of diabetes and on the different kind of muscles observed while was independent on different kind of NDMRs. The resistance to NDMRs was stronger in the later stage of diabetes (16 versus 4 weeks after STZ treatment). Additionally, when monitoring in SOL, diabetes attenuated the actions of neuromuscular blockade more intensely than that in EDL. Nonetheless, the hyposensitivity to NDMRs in diabetes was not relevant for the kind of NDMRs.

• 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.27 no.4
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• pp.311-322
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• 1994

This study was conducted to compare the effects of four types of dietary fiber supplementations (cellulose, pectin, guar gum, and polydextrose) on gastrointestinal function, diabetic symptom amelioration and lipid & glucose metabolism in streptozotocin-induced diabetic rats. Six groups of male rats were fed ad libitum dietary fiber-free control diet or one of experimental diets containing 5% dietary fiber for four weeks. All types of dietary fiber supplementation seemed to protect the diabetic animals from the loss of body weight. The primary diabetic symptoms such as polydipsia, polyphasia, polyuria and urinary glucose excretion were ameliorated by cellulose, pectin, and guar gum, but not by polydextrose. Gastrointestinal transit time was significantly shortened and fecal dry weight was significantly increased in all the dietary fiber-supplemented groups except the polydextrose group. Large intestine was significantly lengthened by dietary fiber feeding. The serum triglyceride and total cholesterol levels were effectively lowered by pectin, guar gum and polydextrose. Regardless of their types, the fiber supplementation had no effect on serum HDL-cholesterol. Whereas fasting blood glucose level was significantly lowered by all types of fiber supplementations, glucose tolerance was more effectively improved by pectin and guar gum.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.6
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• pp.1267-1272
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• 1998

In order to investigate the preventive and therapeutic of royal jelly on diabetes, the levels of blood glucose and serum lipids as well as the number of blood cells were determined in streptozotocin(STZ) diabetic rats. Rats were divided into seven groups. The RJ group was administered royal jelly and the STZ group was treated with streptozotocin to induce diabetes. To determine the preventive effect, diabetes was induced after administration of royal jelly for 2 weeks in group RS1/RS2. In group SR1/SR2 diabetic rats were administered royal jelly for 2 weeks to investigate the therapeutic effect. After 3 weeks, the body weight was reduced in STZ and SR1 groups and food intake was increased in the STZ, RS1 and SR1 groups. The blood glucose level was similar to the control group in the RJ, RS1 and RS2 groups and there was no effect in the other groups. The total lipid and triglyceride level were lower in the SR1 group as compared to STZ, and the total cholesterol level was higher in the STZ group. The index of atherogenesis was lower in the RJ and SR1 groups compared to the normal group. The number of red blood cells and hemoglobin was higher in the RJ and SR1 groups and the number of white blood cells was higher in the RJ and SR2 groups.

• Nutritional Sciences
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• v.6 no.4
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• pp.201-208
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• 2003

This research was conducted to study the effects of the supplementation of multi-extracts of mori folium (MF) and of exercise on plasma insulin and glucose levels in streptozotocin (STZ)-induced diabetic rats. Eight male Sprague-Dawley rats, 4 weeks old, were assigned to each experimental group and were raised in the laboratory for 10 weeks. The animal groups consisted of a normal-control group, a STZ-control group, 3 STZ-induced diabetic groups supplemented ad libitum with various amounts of MF extracts (MF-720, MF-360, and MF-180 groups), and a STZ-induced diabetic group supplemented with MF-360 along with exercise. In the normal-control group, glucose tolerance tests resulted in the peak blood glucose level being achieved in 15 minutes and a fasting blood glucose level being achieved in 60 minutes. In the STZ-control group, the peak blood glucose level was reached after 60 minutes and, even after 90 minutes, blood glucose shown at a significantly higher level compared to the fasting levels. In the groups supplemented with MF extracts, the blood glucose level peaked after 30 minutes of glucose challenge, and returned to the fasting level after 90 minutes; the MF-360 and MF-360+exercise groups showed the best levels of glucose tolerance. Blood glucose levels in the STZ-induced diabetic groups were significantly higher compared to the normal-control group. However, after 7 weeks of supplementation with MF extracts, a significant lowering of blood glucose levels was observed in all groups supplemented with the MF extract. The best effect was observed in the group given MF extract combined with exercise. Compared to the normal-control group, blood insulin levels were significantly lower in all STZ-induced diabetic groups; however, a significantly higher level of insulin was observed in the groups given MF extracts compared to the STZ-control group. This study shows that the supplementation of MF extracts in STZ-induced diabetic rats resulted in increased blood insulin levels and lower blood glucose levels.

• 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.