Diabetes & Metabolism Journal

Original Articles

Protective Effects of Lithospermic Acid B on Diabetic Nephropathy in OLETF Rats Comparing with Amlodipine and Losartan.: Eun Seok Kang, Beom Seok Kim, Chul Hoon Kim, Gi Ho Seo, Seung Jin Han, Sung Wan Chun, Kyu Yeon Hur, Chul Woo Ahn, Hunjoo Ha, Mankil Jung, Bong Soo Cha, Hyun Chul Lee; Korean Diabetes J. 2008;32(1):10-20. Published online February 1, 2008; DOI: https://doi.org/10.4093/kdj.2008.32.1.10

2,729 View
21 Download
1 Crossref

BACKGROUND
Lithospermic acid B (LAB), an active component isolated from Salvia miltiorrhizae, has been reported to have renoprotective effects in type 1 and type 2 diabetic animal models. We examined the effects of LAB on the prevention of diabetic nephropathy compared with amlodipine, a calcium channel blocker, and losartan, an angiotensin receptor blocker, in Otsuka Long-Evans-Tokushima Fatty (OLETF) rats, an animal model of type 2 diabetes. METHODS: LAB (20 mg/kg), amlodipine (10 mg/kg), or losartan (10 mg/kg) was given orally once daily to 10-week-old male OLETF rats for 28 weeks. RESULTS: None of LAB, losartan, and amlodipine exhibited effects on blood glucose levels. Treatment with amlodipine or losartan resulted in similar reductions in blood pressure; however, LAB was less effective in lowering blood pressure. Albuminuria was markedly suppressed by losartan and LAB, but not by amlodipine. LAB treatment decreased levels of renal lipid peroxidation, monocyte chemoattractant protein-1 (MCP-1), and transforming growth factor-beta1 (TGF-beta1). CONCLUSION: These results suggest that LAB has beneficial effects on the diabetic nephropathy in OLETF rats by decreasing oxidative stress and inflammation as potent as losartan.

Citations

Citations to this article as recorded by

An Overview on Naturally Occurring Phytoconstituent: Lithospermic Acid
Bhupesh Chander Semwal, Amjad Hussain, Sonia Singh
The Natural Products Journal.2024;[Epub] CrossRef

Thiazolidinediones on Insulin Resistance and Insulin Secretion in Obese Diabetic OLETF Rats.: Jung hyun Noh, Seung hyun Hong, Kyoung hee Lee, Kyoung Min Min, Tae young Yang, Myung shik Lee, Kwang won Kim, Moon kyu Lee; Korean Diabetes J. 2007;31(1):33-43. Published online January 1, 2007; DOI: https://doi.org/10.4093/jkda.2007.31.1.33

2,247 View
21 Download

Abstract PDF: BACKGROUND
Thiazolidinediones are synthetic peroxisome proliferator-activated receptor-gamma agonists that decrease insulin resistance but, as in vitro and in vivo studies suggest, may have direct beneficial effects on pancreatic beta cells. Here, we investigated the effects of thiazolidinediones (TZDs) on the insulin resistance, beta-cell mass and insulin secretion in obese diabetic OLETF rats. METHODS: We studied insulin resistance (by hyperinsulinemic euglycemic clamp) and insulin secretion (by hyperglycemic clamp) in TZDs administered OLETF and LETO rats. Histologic alterations of the islets were observed and beta-cell mass was also measured by point counting method. RESULTS: Chronic administration of troglitazone (TGZ, 0.15%) or pioglitazone (PGZ, 0.02%) prevented the development of glucose intolerance in OLETF rats, as assessed by oral glucose tolerance test. There was significant difference in submaximal glucose infusion rate between TGZ-treated and untreated OLETF rats during euglycemic clamp studies at 24 weeks of age. At 16 and 24 weeks of ages, beta-cell mass significantly increased in TGZ-treated OLETF rats compared to untreated animals. At 19 weeks and 30 weeks of age, first-phase insulin secretion was not different in PGZ-treated OLETF rats from untreated OLETF rats during hyperglycemic clamp study. At 30 weeks of age, late-phase insulin secretion was decreased in PGZ-treated OLETF rats compared to untreated OLETF rats. The expression of alpha-smooth muscle actin, a marker of activated pancreatic stellate cells that are involved in the fibrosis of the pancreas, in the islets was suppressed by TGZ treatment at 24 weeks of age. CONCLUSION: The treatment of TGZ prevented the development of diabetes, and increased insulin sensitivity and pancreatic beta-cell mass in OLETF rats. These results might be related with the suppression of pancreatic stellate cells. Insulin secretion was not affected by PGZ treatment.

Effects of Caloric Restriction on the Expression of PGC-1 and PPARs mRNA in Liver of Otsuka Long-Evans Tokushima Fatty Rats.: Sang Yong Kim, Jin Hwa Kim, Hak Yeon Bae, Byoung Rai Lee; Korean Diabetes J. 2006;30(3):161-169. Published online May 1, 2006; DOI: https://doi.org/10.4093/jkda.2006.30.3.161

2,024 View
26 Download

Abstract PDF: BACKGROUND
Gluconeogenesis is strongly stimulated during fasting and is aberrantly activated in diabetes mellitus. PPARgamma-coactivator 1 (PGC-1) and Peroxisome proliferator -activated receptors (PPARs) costimulate the expression of key enzymes of gluconeogenetic pathway. This study was performed to evaluate the response to dietary caloric restriction (CR) on the PPARs and PGC-1 expression in liver of diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats. METHODS: Diabetic OLETF rats (male, 24 weeks) and Long-Evans Tokushima Otsuka (LETO) rats (male, 24 weeks) were used in this study. Liver PPARs and PGC-1 mRNA, and blood glucose levels were investigated at 1, 2, and 3 weeks after the beginning of 30% CR. PPARs and PGC-1 mRNA were determined by RT-PCR and blood glucose levels were measured by spectrophotometric assay. RESULTS: The liver PGC-1 mRNA expressions were increased to 19% in non-diabetic LETO rats but significant change was not observed in diabetic OLETF rats by 30% CR. The liver PPARgamma mRNA expressions were not changed in non-diabetic LETO rats but increased to 23% in diabetic OLETF rats by 30% CR. The difference of PPARalpha and PPARbeta mRNA expressions in liver of OLETF and LETO rats were not observed. CONCLUSION: The liver PPARgamma and PGC-1 expression response to CR are altered in OLETF rats compared to in LETO rats. These findings suggested that PPARgamma and PGC-1 expression control system altered in diabetic OLETF rat liver and altered PPARgamma and PCG-1 expression may some roles on the aberrantly activated gluconeogenesis in diabetes mellitus.

Protective Effects of Lithospermate B on Diabetic Nephropathy in OLETF Rat.: Hyun Joo Lee, Geun Taek Lee, Eun Seok Kang, Kyu Yeon Hur, Zheng Shan Zhao, Chul Woo Ahn, Hun Joo Ha, Man Kil Jung, Bong Soo Cha, Hyun Chul Lee; Korean Diabetes J. 2005;29(4):322-332. Published online July 1, 2005

1,171 View
19 Download

Abstract PDF: BACKGROUND
Magnesium lithospermate B(LAB), an active component isolated from Salvia milltiorrhizae, has been reported to have renoprotective effects in type 1 diabetic animal model. The purpose of this study was to examine the effects of LAB on the prevention of diabetic nephropathy in Otsuka Long-Evans Tokushima Fatty(OLETF) rat which is regarded as an animal model of type 2 diabetes. METHODS: Ten microgram of LAB/kg or Vehicle(PBS) was given orally once daily to 10-week-old male OLETF rats and LETO rats for 40 weeks. Intra-peritoneal glucose tolerance test was performed at 50 weeks. 24 hr urinary protein excretion amounts were measured. Lipid peroxidation, TGF-beta1 and ED-1 of renal cortex were measured. RESULTS: The mean body weight of LAB+OLETF was not significantly different from that of OLETF rats. LAB treatment decreased proteinuria, lipid peroxidation, and free fatty acid in OLETF rats without decrease in the plasma glucose concentration. Also, LAB inhibited the progression of glomerular hypertrophy and mesangial expansion. LAB effectively decreased ED-1 positive cells, ECM expansion, and TGF-beta1 level in the renal cortex of OLETF rats. CONCLUSIONS: These results suggest that the beneficial effects of LAB on the diabetic renal damage in the OLETF rats may depend on a mechanism of decreasing oxidative stress. LAB might be a new therapeutic agent for the prevention of nephropathy in type 2 diabetes as well as type 1 diabetes.

High Carbohydrate Diet Effects on the Development of Diabetes Mellitus and Modification of Pancreatic Islets in OLETF Rats.: Sung Ki Kim, Seong Bin Hong, Hwi Ra Park, Eun A Kim, Kyung Wook Lee, Moon Suk Nam, Yong Seong Kim; Korean Diabetes J. 2004;28(3):187-198. Published online June 1, 2004

1,122 View
20 Download

Abstract PDF: BACKGROUND
Diet has long been believed to be an important risk factor for type 2 diabetes. The composition of carbohydrates in the diet was higher in the past, where as now it is considerably reduced in the diet of Korean peoples, which is probably associated with the risk of developing type 2 diabetes. The aim of the present study was to investigate the long-term effect of high carbohydrate/low protein diets on the glucose and lipid metabolism and the pancreatic islet in OLETF(Otsuka Long-Evans Tokushima Fatty) rats, the animal model of type 2 diabetes. METHODS: Seven week old male OLETF rat were fed a high carbohydrate/low protein diet(carbohydrate 71.0%, fat 14.5%, protein 14.5%) as the experimental group, with an ordinary chow diet(carbohydrate 63.5%, fat 14.5%, protein 22%) fed to the controls. The plasma insulin, lipid profiles, free fatty acid and oral glucose tolerance were analyzed at 16 and 32 weeks. After the glucose tolerance test, the pancreas was excised, and immunohistochemical staining was conducted for the islet morphology and insulin mRNA to quantify the insulin secretory capacity. RESULTS: The basal glucose levels tended to be higher in the control group, but with no significant statistical difference. There were no differences in the serum insulin, total cholesterol, triglyceride, HDL-cholesterol and plasma free fatty acid levels between the two groups. The pancreatic islets of the control group showed multilobulation, with fibrotic changes; where as those of the experimental group were maintained normal profiles. A higher expression of insulin mRNA was observed in the experimental than in the control group. CONCLUSION: A high carbohydrate diet induced lower body weight increases, and protected against beta cell injury and decreased the development of abnormal glucose tolerance in OLETF rats. This may explain the growing incidence of diabetes with respect to the change in carbohydrate composition in the diet of Korean peoples. However, whether the protective effect of a high carbohydrate diet, against the development of diabetes in OLETF rats, can be attributed to small weight increases or if the change in food composition itself, or both needs to be determined.

Effect of Glycosaminoglycan on Proteinuria and Urinary N-acetyl- -D-Glucosaminidase Excretion in Otsuka Long-Evans Tokushima Fatty (OLETF) Rats.: Kyung Mook Choi, Dae Ryong Cha, Sang Youb Han, Dong Rim Kim, Nan Hee Kim, Sei Hyun Baik, Dong Seop Choi; Korean Diabetes J. 2000;24(5):533-540. Published online January 1, 2001

1,025 View
16 Download

Abstract: BACKGROUND
Increased loss of proteoglycan (PG) characterized by an increased loss of anionic charges in the basement membrane has been considered as one of main factors causing urinary loss of albumin. The glycosaminoglycans (GAGs) are linear polymers of repeated disaccharides and the GAG chains are covalently bound to core proteins, forming proteoglycans. It is known that urinary N-acetyl- -D-glucosaminidase (NAG) excretion is a sensitive marker of renal damage and is increased before other renal functional parameters. The aim of this study was to investigate whether GAG treatment is capable of influencing urinary protein and NAG excretion in Otsuka Long-Evans Tokushima Fatty (OLETF) rats which are known as type 2 diabetic animal model. METHODS: Fifteen male OLETF rats and twenty male Long-Evans Tokushima Otsuka (LETO) rats were used for this study. LETO rats are non-diabetic control rats. All OLETF rats were randomly assigned to 2 groups: control group (n=10) given only tap water and GAG group (n=5) feeding with GAG 10 mg/kg from 7 weeks to 55 weeks of age. Measurement of body weight, blood glucose, serum BUN and creatinine was performed periodically. 24-hour urine collection for measurement of urinary protein and NAG excretion was done at 17, 25, 37, 46, 55 weeks of age. RESULTS: 1) OLETF rats showed higher body weight, blood glucose, 24-hour urinary protein and NAG excretion compared with LETO rats. But serum concentration of BUN and creatinine were not different between OLETF and LETO rats. 2) GAG-treated OLETF rats exhibited lower urinary protein/creatinine excretion (17.48+/-0.50 vs 22.49+/-0.11 mg/mg Cr, p< 0.05) and NAG (17.40+/-5.94 vs 43.73+/- 7.44 nmol/h/mg Cr, p< 0.05) excretion compared with non-treated OLETF rats. But body weights, blood glucose, serum concentration of BUN and creatinine were not different between GAG-treated OLETF rats and non-treated OLETF rats. CONCLUSION: 1) The urinary excretion of NAG may be a possible early marker of diabetic nephropathy in OLETF rats. 2) Urinary protein and NAG excretion were decreased in the GAG-treated OLETF rats. GAG seems to have a protective effect against development of diabetic nephropathy.

First
Prev
Page of 1
Next
Last

Search