Diabetic Goto-Kakizaki Rats Research Articles

Restoration of Proresolution Pathway with Exogenous Resolvin D1 Prevents Sevoflurane-Induced Cognitive Decline by Attenuating Neuroinflammation in the Hippocampus in Rats with Type 2 Diabetes Mellitus.

Sevoflurane (SEV), a commonly used volatile anesthetic, has been shown to cause cognitive decline in diabetic rats by aggregating neuroinflammation in the hippocampus, but the underlying mechanisms are unknown. Recent evidence suggests that neuroinflammation could be a consequence of failure to resolve inflammation by specialized pro-resolving lipid mediators including resolvin D1 (RvD1). Here we first examined whether type 2 diabetes mellitus (DM) alters RvD1 proresolution pathway. Diabetic Goto-Kakizaki (GK) rats and non-diabetic Wistar rats received control or 2.6% SEV exposure for 4 h. Seven days after exposure, GK control rats, compared with Wistar control rats, had significantly lower RvD1 levels in plasma and CSF and decreased RvD1 receptor FPR2 expression in the hippocampus. SEV increased RvD1 levels in plasma and CSF and FPR2 expression in the hippocampus in Wistar rats but not in GK rats. We next examined whether RvD1 treatment of GK rats can prevent SEV-induced neuroinflammation and cognitive decline. GK rats received control, SEV or SEV and once-daily treatment with exogenous RvD1 (0.2 ug/kg, ip) for 7 days. RvD1 administration markedly increased RvD1 levels in plasma and CSF and FPR2 expression in the hippocampus in GK rats received SEV. Compared with GK control rats, GK rats received SEV exhibited shorter freezing times in trace fear conditioning task, which was accompanied by increased microglia activity and pro-inflammatory cytokine expression in the hippocampus. RvD1 administration attenuated SEV-induced increases in microglia activity and pro-inflammatory cytokine expression in the hippocampus, preventing cognitive decline in GK rats. Notably, neither SEV nor RvD1 altered metabolic parameters in GK rats. The results suggest that RvD1 proresolution pathway is impaired in the brain of diabetic GK rats. which may enhance the susceptibility to SEV, contributing to neuroinflammation and cognitive decline. Restoration of RvD1 proresolution pathway in diabetic GK rats with exogenous RvD1 can prevent SEV-induced cognitive decline by attenuating neuroinflammation in the hippocampus.

Impairment of the angiogenic process may contribute to lower success rate of root canal treatments in diabetes mellitus.

To investigate the association between root canal treatment outcome, diabetes mellitus, and alterations of the angiogenic process. A retrospective observational study was conducted in healthy (control group, CG) and diabetic (type II diabetes mellitus group, DG) patients after root canal treatment. The follow-up appointments were performed to clinically and radiographically observe symptoms, the healing of periapical lesions and the quality of root fillings. In the animal model study, diabetic Goto-Kakizaki (GK) rats and control Wistar rats were used. After 21days of pulp exposure and the development of apical periodontitis (AP), the mandibles were removed for scintigraphic, radiographic, histopathological and molecular analyses. Chi-square tests were performed to examine the variables related to endodontic outcome and differences between animal groups were assessed using the Student's t-test. The group of patients with diabetes had a significantly lower rate of success following root canal treatment than the CG (p<.001). Logistic regression suggested that diabetes is a risk factor for success of root canal treatment. In the animal study, GK rats had significantly higher fasting glycaemia at t0 and t21 (p<.001) and triglycerides levels (p<.05) and area under the curve (AUC) during the insulin tolerance test at t21 (p<.001). AP area was significantly greater in GK rats (p<.05). Histologically, diabetic rats had increased signs of periodontal ligament inflammation 21days after the induction of apical periodontitis, with fibro-hyaline matrix filling and vessel with undefined walls. Wistar rats had significantly increased vascular endothelial growth factor (VEGF) levels and VEGF/Ang-2 ratio 21days after AP induction (p<.08; p<.07). GK rats had intrinsically lower levels of VEGF than control rats (p<.05), which did not change after AP. Diabetes mellitus should be considered as an important factor in the prognosis of root canal treatment and its outcomes over time. Future strategies to improve angiogenesis and tissue repair should be pursued to achieve better root canal treatment outcomes in diabetic patients.

The Goto Kakizaki rat: Impact of age upon changes in cardiac and renal structure, function.

Patients with diabetes are at a high risk for developing cardiac dysfunction in the absence of coronary artery disease or hypertension, a condition known as diabetic cardiomyopathy. Contributing to heart failure is the presence of diabetic kidney disease. The Goto-Kakizaki (GK) rat is a non-obese, non-hypertensive model of type 2 diabetes that, like humans, shares a susceptibility locus on chromosome 10. Herein, we perform a detailed analysis of cardio-renal remodeling and response to renin angiotensin system blockade in GK rats to ascertain the validity of this model for further insights into disease pathogenesis. Study 1: Male GK rats along with age matched Wistar control animals underwent longitudinal assessment of cardiac and renal function for 32 weeks (total age 48 weeks). Animals underwent regular echocardiography every 4 weeks and at sacrifice, early (~24 weeks) and late (~48 weeks) timepoints, along with pressure volume loop analysis. Histological and molecular characteristics were determined using standard techniques. Study 2: the effect of renin angiotensin system (RAS) blockade upon cardiac and renal function was assessed in GK rats. Finally, proteomic studies were conducted in vivo and in vitro to identify novel pathways involved in remodeling responses. GK rats developed hyperglycaemia by 12 weeks of age (p<0.01 c/w Wistar controls). Echocardiographic assessment of cardiac function demonstrated preserved systolic function by 48 weeks of age. Invasive studies demonstrated left ventricular hypertrophy, pulmonary congestion and impaired diastolic function. Renal function was preserved with evidence of hyperfiltration. Cardiac histological analysis demonstrated myocyte hypertrophy (p<0.05) with evidence of significant interstitial fibrosis (p<0.05). RT qPCR demonstrated activation of the fetal gene program, consistent with cellular hypertrophy. RAS blockade resulted in a reduction blood pressure(P<0.05) cardiac interstitial fibrosis (p<0.05) and activation of fetal gene program. No significant change on either systolic or diastolic function was observed, along with minimal impact upon renal structure or function. Proteomic studies demonstrated significant changes in proteins involved in oxidative phosp4horylation, mitochondrial dysfunction, beta-oxidation, and PI3K/Akt signalling (all p<0.05). Further, similar changes were observed in both LV samples from GK rats and H9C2 cells incubated in high glucose media. By 48 weeks of age, the diabetic GK rat demonstrates evidence of preserved systolic function and impaired relaxation, along with cardiac hypertrophy, in the presence of hyperfiltration and elevated protein excretion. These findings suggest the GK rat demonstrates some, but not all features of diabetes induced "cardiorenal" syndrome. This has implications for the use of this model to assess preclinical strategies to treat cardiorenal disease.

Dose-Effect of a 6-week treatment with PEP2DIA®, a Patented Milk Protein Hydrolysate on Sucrose Tolerance in Goto-Kakizaki (GK) Rats

Abstract Objectives The study was designed to evaluate the dose-effect of PEP2DIA(r)(PEP), a milk protein hydrolysate on glycemic control of type 2 diabetic Goto-Kakizaki (GK) rats treated for 6 weeks. Methods Rats (n = 10) were treated with PEP solubilized in spring water by oral gavage once a day for 6 weeks. The effects of a 6-week-administration of PEP (63 mg/kg, 88.6 mg/kg and 126 mg/kg per os) were evaluated on sucrose tolerance and insulin response to sucrose in type 2 diabetic GK rats from weaning (3 weeks) to adult age (9 weeks). Circulating GLP-1 concentration and DDP-4 activity, α-glucosidase activity in duodenum and jejunum, Fatty Acid Synthase (FAS) and Sterol regulatory element-binding protein 1 (SREBP-1c) gene expressions in liver and retroperitoneal adipose tissue were also measured. PEP is a patented milk protein hydrolysate containing AP dipeptides which inhibit alpha glucosidase. The alpha-glucosidase inhibitor Acarbose (40 mg/kg) was used as reference. Results The 6 week-treatment with PEP at 3 doses improved sucrose tolerance with the best effect at the dose of 63 mg/kg. Insulin response to sucrose was lower than control after PEP treatment at all the doses tested with the strongest decrease with 63 mg/kg of PEP. This decrease in insulin response seems to be at least in part the consequence of an improvement of the insulin resistance of the GK rats. At the lowest dose tested (63 mg/kg), FAS and SREBP-1c gene expressions were significantly decreased in retroperitoneal adipose tissue of GK rats, suggesting that PEP inhibited lipogenesis. PEP treatment induced strong increases in GLP-1 plasma level at all the doses tested but the difference reached significance only with 63 and 126 mg/kg of PEP. An inhibition of alpha-glucosidase in duodenum but not in jejunum was observed after the 6-week-treatment with PEP. Moreover, in retroperitoneal adipose tissue, PEP at the lowest dose tested (63 mg/kg), significantly decreased gene expression of both SREBP-1c and FAS, suggesting a beneficial effect on triglyceride accumulation in adipose tissue Conclusions These results showed that PEP2DIA(r) could have a beneficial effect on glycemic control of type 2 diabetic GK rats and suggest that this milk protein hydrolysate should be beneficial Impaired Fasting Glucose or Impaired Glucose Tolerance subjects for delaying the progression to overt type 2 diabetes. Funding Sources INGREDIA S.A.

Trans-resveratrol imparts disparate effects on transcription of DNA damage sensing/repair pathway genes in euglycemic and hyperglycemic rat testis

Prevention or repair of DNA damage is critical to inhibit carcinogenesis in living organisms. Using quantitative RT2 Profiler™ PCR array, we investigated if trans-resveratrol could modulate the transcription of DNA damage sensing/repair pathway genes in euglycemic and non-obese type 2 diabetic Goto-Kakizaki rat testis. Trans-resveratrol imparted disparate effects on gene expressions. In euglycemic rats, it downregulated 79% and upregulated 2% of genes. However, in diabetic rats, it upregulated only 2% and downregulated 4% of genes. As such, diabetes upregulated 16% and downregulated 4% of genes. Trans-resveratrol normalized the expression of 9 (60%) out of 15 upregulated genes in diabetic rats. In euglycemic rats, trans-resveratrol inhibited ATM/ATR, DNA damage repair, pro-cell cycle progression, and apoptosis signaling genes. However, it increased Cdkn1a and Sumo1, indicating cell cycle arrest, apoptosis, and cytostasis in conjunction with increased DNA double-strand breaks and apoptosis. Diabetes increased DNA damage and apoptosis but did not affect ATM/ATR and double-strand break repair genes, although it increased few single-strand repair genes. Diabetes increased Abl1 and Sirt1, which may be related to apoptosis, but their increase may well suggest the enhanced cell cycle progression and putative carcinogenicity. The transcription of Rad17 and Smc1a increased in diabetic rats indicating G2 phase arrest and increases in a few DNA single-strand breaks repair genes suggesting DNA damage repair. Trans-resveratrol inhibits the cell cycle and causes cell death in euglycemic rat testis but normalizes diabetes-induced genes related to DNA damage and cell cycle control, suggesting its usefulness in maintaining DNA integrity in diabetes.

Multiparticulate Systems of Ezetimibe Micellar System and Atorvastatin Solid Dispersion Efficacy of Low-Dose Ezetimibe/Atorvastatin on High-Fat Diet-Induced Hyperlipidemia and Hepatic Steatosis in Diabetic Rats.

The aim of this study was to develop multiparticulate systems with a combination of ezetimibe micellar systems and atorvastatin solid dispersions using croscarmellose as a hydrophilic vehicle and Kolliphor RH40 as a surfactant. The presence of a surfactant with low hydrophilic polymer ratios produces the rapid dissolution of ezetimibe through a drug–polymer interaction that reduces its crystallinity. The solid dispersion of atorvastatin with low proportions of croscarmellose showed drug–polymer interactions sufficient to produce the fast dissolution of atorvastatin. Efficacy studies were performed in diabetic Goto-Kakizaki rats with induced hyperlipidemia. The administration of multiparticulate systems of ezetimibe and atorvastatin at low (2 and 6.7 mg/kg) and high (3 and 10 mg/kg) doses showed similar improvements in levels of cholesterol, triglycerides, lipoproteins, alanine transaminase, and aspartate transaminase compared to the high-fat diet group. Multiparticulate systems at low doses (2 and 6.7 mg/kg of ezetimibe and atorvastatin) had a similar improvement in hepatic steatosis compared to the administration of ezetimibe and atorvastatin raw materials at high doses (3 and 10 mg/kg). These results confirm the effectiveness of solid dispersions with low doses of ezetimibe and atorvastatin to reduce high lipid levels and hepatic steatosis in diabetic rats fed a high-fat diet.

Effect of berberine on hyperglycaemia and gut microbiota composition in type 2 diabetic Goto-Kakizaki rats.

BACKGROUNDA recent investigation showed that the prevalence of type 2 diabetes mellitus (T2DM) is 12.8% among individuals of Han ethnicity. Gut microbiota has been reported to play a central role in T2DM. Goto-Kakizaki (GK) rats show differences in gut microbiota compared to non-diabetic rats. Previous studies have indicated that berberine could be successfully used to manage T2DM. We sought to understand its hypoglycaemic effect and role in the regulation of the gut microbiota.AIMTo determine whether berberine can regulate glucose metabolism in GK rats via the gut microbiota.METHODSGK rats were acclimatized for 1 wk. The GK rats were randomly divided into three groups and administered saline (Mo), metformin (Me), or berberine (Be). The observation time was 8 wk, and weight, fasting blood glucose (FBG), insulin, and glucagon-like peptide-1 (GLP-1) were measured. Pancreatic tissue was observed for pathological changes. Additionally, we sequenced the 16S rRNA V3-V4 region of the gut microbiota and analysed the structure.RESULTSCompared with the Mo group, the Me and Be groups displayed significant differences in FBG (P < 0.01) and GLP-1 (P < 0.05). A significant decrease in weight and homeostatic model assessment-insulin resistance was noted in the Be group compared with those in the Me group (P < 0.01). The pancreatic islets of the Me- and Be-treated rats showed improvement in number, shape, and necrosis compared with those of Mo-treated rats. A total of 580 operational taxonomic units were obtained in the three groups. Compared to the Mo group, the Me and Be groups showed a shift in the structure of the gut microbiota. Correlation analysis indicated that FBG was strongly positively correlated with Clostridia_UCG-014 (P < 0.01) and negatively correlated with Allobaculum (P < 0.01). Body weight showed a positive correlation with Desulfovibrionaceae (P < 0.01) and a negative correlation with Akkermansia (P < 0.01). Importantly, our results demonstrated that Me and Be could significantly decrease Bacteroidetes (P < 0.01) and the Bacteroidetes/Firmicutes ratio (P < 0.01). Furthermore, Muribaculaceae (P < 0.01; P < 0.05) was significantly decreased in the Me and Be groups, and Allobaculum (P < 0.01) was significantly increased.CONCLUSIONBerberine has a substantial effect in improving metabolic parameters and modulating the gut microbiota composition in T2DM rats.

Effect of Shenzhu Tiaopi granule on hepatic insulin resistance in diabetic Goto-Kakizakirats via liver kinase B1/adenosine 5'-monophosphate/mammalian target of rapamycin signaling pathway.

To observe the therapeutic effect of Shenzhu Tiaopi granule (, STG) on insulin resistance (IR) in the liver of diabetic Goto-Kakizaki (GK) rat and investigate underlying mechanisms. Ten 12-week-old male Wistar rats were assigned as normal control (NC) group, while 40 12-week-old male specific-pathogen-free GK rats were randomly divided into four experimental groups, 10 diabetic rats each. Animals were fed with a normal diet. Fasting blood glucose (FBG), water intake, and body weight were recorded during 6 weeks of daily single-dose treatment: STG low-dose group, 4.5 g/kg (STG-L); STG high-dose group,9 g/kg (STG-H); metformin group, 0.1 g/kg (MET); model control (MC) and NC groups, equal volume of 0.9% NaCl solution. The serum fasting insulin (FINS), C-Peptide and IR index (HOMA-IR) were detected every 2 weeks during treatment and glucose tolerance was measured in the 3rd day before the material was taken. After the 6-week STG treatment, Liver tissues were processed for hematoxylin-eosin staining to perform light microscopy analysis and for assessing expression and distribution of insulin receptor substrates (IRS-1) and glucose transporter (GLUT-4) by immunohistochemistry analysis. Expression levels of liver kinase B1 (LKB1) / adenosine 5'-monophosphate-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) pathway proteins, including LKB1, phospho-AMPK (p-AMPK)/AMPK, phospho-mTOR (p-mTOR)/mTOR, and ribosomal protein S6 kinase polypeptide 1 (S6K1),were detected by Western blotting. STG significantly reduced the FBG level and liver fat deposition in diabetic GK rats. After STG treatment completion, FINS, HOMA-IR, C-Peptide and area under blood glucose curve (AUC) were lower in STG groups than in the MC group, indicating that IR was reduced and liver fat lesions were resolved. In liver tissues, STG groups displayed significantly higher IRS-1 and GLUT-4 expression than the MC group, along with increasedLKB1 and p-AMPK/AMPK expression and decreased p-mTOR/mTOR and phospho-S6K1expression, suggesting that STG stimulatedLKB1 activation of AMPK and suppressed them TOR/S6K1 downstream pathway. Growing GK rats developed hepatic IR, but STG treatment significantly improved hyperglycemia and IR and resolved hepatic fatty lesions. Interestingly, STG treatment stimulated the expression of IRS-1 and GLUT-4 in the liver of diabetic GK rats, indicating a potential involvement in the regulation of theLKB1/AMPK/mTOR signaling pathway.

Single-Cell Transcriptomics Reveals That Metabolites Produced by Paenibacillus bovis sp. nov. BD3526 Ameliorate Type 2 Diabetes in GK Rats by Downregulating the Inflammatory Response.

Chronic low-grade inflammation is widely involved in the development and progression of metabolic syndrome, which can lead to type 2 diabetes mellitus (T2DM). Dysregulation of proinflammatory and anti-inflammatory cytokines not only impairs insulin secretion by pancreatic β-cells but also results in systemic complications in late diabetes. In our previous work, metabolites produced by Paenibacillus bovis sp. nov. BD3526, which were isolated from Tibetan yak milk, demonstrated antidiabetic effects in Goto–Kakizaki (GK) rats. In this work, we used single-cell RNA sequencing (scRNA-seq) to further explore the impact of BD3526 metabolites on the intestinal cell composition of GK rats. Oral administration of the metabolites significantly reduced the number of adipocytes in the colon tissue of GK rats. In addition, cluster analysis of immune cells confirmed that the metabolites reduced the expression of interleukin (IL)-1β in macrophages in the colon and increased the numbers of dendritic cells (DCs) and regulatory T (Treg) cells. Further mechanistic studies of DCs confirmed that activation of the WNT/β-catenin pathway in DCs promoted the expression of IL-10 and transforming growth factor (TGF)-β, thereby increasing the number of Treg cells.

Soy isoflavones ameliorate the cognitive dysfunction of Goto-Kakizaki rats by activating the Nrf2-HO-1 signalling pathway.

Soy isoflavones (SIF) are soybean phytochemicals that are considered to be biologically active components that protect from neurodegenerative diseases. In this study, the therapeutic effect of SIF was evaluated in a diabetic Goto-Kakizaki (GK) rat model. Twenty male GK rats were randomly divided into diabetes mellitus (DM) model group and SIF+DM group (n=10 in each group). Twenty age-matched male Wistar rats were randomly divided into control group (CON group) and CON+SIF group, with 10 rats in each group. The learning and memory functions of the animals were determined by the Morris water maze (MWM) test. Hematoxylin-eosin staining (HE) was performed to examine pyramidal neuron loss in the CA1 area of the hippocampus. Markers of oxidative stress (OS) were measured to evaluate oxidative stress-mediated injury. RT-PCR and western blotting were used to analyze the expression of nuclear factorerythroid2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1) and NAD(P)H dehydrogenase quinone1 (NQO1). Treatment with SIF for 4 weeks alleviated the cognitive dysfunction of the GK rats as determined by the MWM test. Moreover, SIF treatment also reduced diabetes-related oxidative reactions. In addition, SIF enhanced the expression of Nrf2, HO-1 and NQO1, suggesting a potential antioxidation mechanism for the effect of SIF. These findings suggest that SIF can be considered candidates for inhibiting the progression of diabetes-induced cognitive dysfunction, provide novel insights into the antioxidant effect of SIF and further strengthen the link between oxidative stress and diabetes.

Diet-induced obesity enhances postprandial glucagon-like peptide-1 secretion in Wistar rats, but not in diabetic Goto-Kakizaki rats.

Glucagon-like peptide-1 (GLP-1) is postprandially secreted from enteroendocrine L-cells and enhances insulin secretion. Currently, it is still controversial whether postprandial GLP-1 responses are altered in obesity and diabetes. To address the issue and to find out possible factors related, we compared postprandial GLP-1 responses in normal rats and in diabetic rats chronically fed an obesogenic diet. Male Wistar rats and diabetic Goto-Kakizaki (GK) rats were fed either a control diet or a high-fat/high-sucrose (HFS, 30 % fat and 40 % sucrose) diet for 26 weeks. Meal tolerance tests were performed for monitoring postprandial responses after a liquid diet administration (62·76 kJ/kg body weight) every 4 or 8 weeks. Postprandial glucose, GLP-1 and insulin responses in Wistar rats fed the HFS diet (WH) were higher than Wistar rats fed the control diet (WC). Although GK rats fed the HFS diet (GH) had higher glycaemic responses than GK rats fed the control diet (GC), these groups had similar postprandial GLP-1 and insulin responses throughout the study. Jejunal and ileal GLP-1 contents were increased by the HFS diet only in Wistar rats. Furthermore, mRNA expression levels of fatty acid receptors (Ffar1) in the jejunum were mildly (P = 0·053) increased by the HFS diet in Wistar rats, but not in GK rats. These results demonstrate that postprandial GLP-1 responses are enhanced under an obesogenic status in normal rats, but not in diabetic rats. Failure of adaptive enhancement of GLP-1 response in GK rats could be partly responsible for the development of glucose intolerance.

Greater impairment of energy metabolism and coronary flow in type 2 diabetic female rats than in male during myocardial ischemia-reperfusion injury

Type 2 diabetic women are at greater risk of cardiovascular (CV) diseases than men, but the mechanisms involved are still poorly understood. The objective of this study was to investigate the effect of sex on the myocardial tolerance to ischemia-reperfusion (IR) injury in type 2 diabetic Goto-Kakizaki (GK) rats. We performed ex vivo experiments on isolated perfused hearts to evaluate tolerance to IR injury of male and female GK and Wistar rats. We simultaneously measured energy metabolism by 31P magnetic resonance spectroscopy, myocardial function and coronary flow. At the end of the experiments, biochemical analyses were performed on plasma and hearts. GK rats had cardiac hypertrophy and higher glycemia than control rats, without effect of sex. Basal oxidative stress was significantly higher only in female GK rats in comparison to other groups, with higher plasmatic level of 8-iso-PGF2α. Male and female GK rats had impaired cardiac function before and after IR injury in comparison to respective controls. Interestingly, female GK rats had greater impairment of cardiac function than male GK during reperfusion, associated with decreased ATP and PCr level, and higher impairment of coronary flow. Biochemical analyses in hearts showed downward trend in SIRT1 expression in GK rats versus control groups, without sex-effect. Citrate synthase activity and SIRT3 protein expression were similar between groups. These results indicate that sex influences the myocardial tolerance to IR injury in type 2 diabetes. Mitochondrial and endothelial dysfunction might explain why female GK have lower myocardial function during reperfusion. These results may be related to the higher risk of cardiovascular complications among type 2 diabetic women.

Enterococcus Faecium Strain R30 Attenuates Capillary Regression In Type 2 Diabetic Muscle

It is widely accepted that diabetes affects the peripheral vascular bed. We found that Enterococcus faecium strain R30 (R30) supplementation caused increased velocity of red blood cells in capillaries of skeletal muscle. PURPOSE: We determined the effects of R30 supplementation on the three-dimensional capillary structure in the soleus muscle of Goto-Kakizaki (GK) diabetic rats. R30 supplementation was chosen, because it may be beneficial in management of skeletal muscle and to be safe for individuals with cardiovascular complications such as those associated with diabetes. METHODS: Thirty-six male (Wistar or GK) rats were assigned randomly either to a control (Con), control with R30 supplementation (Con+R30), diabetes (GK) or diabetes with R30 supplementation (GK+R30) group for 8 weeks. The capillaries of soleus muscle were stained with alkaline phosphatase. In addition, the three-dimensional capillary network of soleus muscle was visualized using a confocal laser scanning technique, and the capillary volume and diameter were measured. RESULTS: The blood glucose levels were higher in the GK and GK+R30 groups than in the Con and Con+R30 groups. There were no significant differences in the capillary-to-fiber ratio between the Con and GK+R30 although the ratio was lower in the GK group than in the Con group. The capillary volume and diameter in the muscle of GK group were lower than those in Con group. Meanwhile, R30 supplementation attenuated the decrease of capillary volume and diameter in diabetic muscle. CONCLUSION: These data suggest that R30 supplementation may be an effective treatment to counter the detrimental effects of type 2 diabetic complications in skeletal muscle.

Danggui Buxue decoction ameliorates lipid metabolic defects involved in the initiation of diabetic atherosclerosis; identification of active compounds.

To determine the constituent compounds of Danggui buxue decoction (DBD) involved and the potential mechanisms mediating its effects, with specific reference to lipids playing a role in the initiation of diabetic atherosclerosis. Liquid chromatography-tandem mass spectrometry was used to identify and quantify the absorbed bioactive compounds (ABCs) present in DBD. Goto-Kakizaki (GK) rats were randomly allocated to a diabetes atherosclerosis (DA) group, a DBD group, and an ABC group (10 per group), which were all high-fat diet-fed. The treated rats were administered DBD (4 g/kg) or ABCs (in amounts equal to those present in DBD) once daily for 28 d, and a control group of Wistar rats were administered vehicle. Body mass gain, fasting blood glucose, and homeostasis assessment of insulin resistance (HOMA- IR) were measured. Serum triglyceride (TG), cholesterol (CHOL), high density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL- C) and tumor necrosis factor-α (TNF-α) concentrations were determined. Hematoxylin and eosin staining and microscopy were used to characterize the abdominal aorta and the expression of lipogenic genes was quantified in this vessel. Seven ABCs were identified in rat serum: ferulic acid, formononetin, calycosin, astragaloside, caffeic acid, ligustilide, and butyphthalide. DBD significantly reduced HOMA-IR, the serum concentrations of TG, CHOL, and LDL-C, and the expression of the lipogenic genes monocyte chemotactic protein 1, Fas, intercellular adhesion molecule 1, and Cd36 in aorta; and significantly increased the mRNA expression of Scd1 in aorta. DBD affects lipid metabolism in the early stage of atherosclerosis in diabetic GK rats, with the mechanism likely involving the regulation of lipid metabolic genes in vessels. The contribution of ABCs to the effect of DBD on lipid metabolism was 24%-101%.

SAT-LB108 Brown Adipose Tissue Activity in Different Insulin Resistance Models in Rats: Lean Goto-Kakizaki and Diet-Induced Obese Wistar Rats

Obesity is growing worldwide and one of the main causes of death. It is highly associated with the development of type 2 diabetes mellitus, insulin resistance, cardiovascular disease, metabolic syndrome, and certain forms of cancer. The presence of two types of adipose tissue, which have the opposing function, has been known for a long time. White adipose tissue (WAT) is the tissue of energy expenditure storage, while Brown adipose tissue (BAT) is characterized to dissipates energy as heat and is required for non-shivering thermoregulation, presents a high thermogenesis capacity, regulating systemic metabolism and participating of the glycemic homeostasis, and displayed a high metabolic activity, which is due the presence of UCP1 (uncoupling protein-1) and through this the ability to dissipate energy, to burn away (extra) food, and it had been a proposal as a potential target to obesity treatment. Was identification a novel type of adipocytes, brite/beige adipocytes, localized within the WAT depots and possess the ability to increase energy expenditure. The BAT activity is regulated by the adrenergic receptor and Sympathetic Nervous System; however, its regulation by the insulin resistance state is not completely elucidated yet. In this study, we evaluated the BAT activity and response different animal models of insulin resistance: lean type 2 diabetic Goto-Kakizaki rats and high-fat diet-induced obese Wistar rats. Animals at eight weeks-old were fed ad libitum with a control diet (Wistar-Control and GK-CD), high-fat diet (Wistar-HFD) and/ or plus condensed milk (wistar-HFD+CM) for eight weeks. To evaluate the BAT activity, 18F-FDG small-animal PET/CT was performed at 30 min after CL316,243 or saline injection. The activity of brown adipose tissue by 18F-FDG uptake sob basal conditions, when injecting saline, not shown a significant difference between the groups, however, shown lower 18F-FDG uptake in animals GK than compared with other groups. After CL 316,243 stimuli a highly specific beta 3- adrenoceptor agonist, the animals GK showed decreased 18F-FDG uptake in brown adipose tissue than the control group (by 56%). The analyze between to the groups sob saline or CL 316, 243 conditions by two-way ANOVA test, showed after stimuli that control group showed increased 18F-FDG uptake when compared to the HFD +CM and GK (by 68,9%) and (by 71%), respectively. The GK animals showed lower 18F-FDG uptake when compared with HFD and HFD+CM groups (by 62,3%) and (by 51%). The 18F-FGD showed decreased BAT activity after CL316,243 stimuli in GK animals. The encephalon18F-FDG uptake, under saline, showed higher uptake the animals HFD when compared with the GK group (by 171,3%). After stimuli CL 316, 243, the HFD group displayed higher 18F-FDG uptake than CM+HFD group and control group (by 35,3%) and (by 56,2%), respectively. The analyze between groups, baseline or CL 316, 243, showed that the baseline the HFD group displayed higher 18F-FDG uptake when compared with GK and CM+HFD group (by 63,1%) and (by 73,4%), respectively. These data showed decreased 18F-FDG uptake in response the stimuli CL 316, 243 in all groups, except GK group. These findings suggest a transition from brown to white adipose tissue in GK rats, a process known as “whitening”.

KGF-2 and FGF-21 poloxamer 407 hydrogel coordinates inflammation and proliferation homeostasis to enhance wound repair of scalded skin in diabetic rats.

ObjectiveThe present study focused on the development of a poloxamer 407 thermosensitive hydrogel loaded with keratinocyte growth factor-2 (KGF-2) and fibroblast growth factor-21 (FGF-21) as a therapeutic biomaterial in a scald-wound model of type-2 diabetes in Goto-Kakizaki (GK) rats.Research design and methodsIn this study, a poloxamer 407 thermosensitive hydrogel loaded with KGF-2 and/or FGF-21 was prepared and its physical and biological properties were characterized. The repairing effects of this hydrogel were investigated in a scald-wound model of type-2 diabetes in GK rats. The wound healing rate, epithelialization, and formation of granulation tissue were examined, and biomarkers reflecting regulation of proliferation and inflammation were quantified by immunostaining and Western blotting. T tests and analyses of variance were used for statistical analysis via Graphpad Prism V.6.0.ResultsA 17.0% (w/w) poloxamer 407 combined with 1.0% (w/w) glycerol exhibited controlled release characteristics and a three-dimensional structure. A KGF-2/FGF-21 poloxamer hydrogel promoted cellular migration without apoptosis. This KGF-2/FGF-21 poloxamer hydrogel also accelerated wound healing of scalded skin in GK rats better than that of a KGF-2 or FGF-21 hydrogel alone due to accelerated epithelialization, formation of granulation tissue, collagen synthesis, and angiogenesis via inhibition of inflammatory responses and increased expression of alpha-smooth muscle actin (α-SMA), collagen III, pan-keratin, transforming growth factor-β (TGF-β), vascular endothelial growth factor (VEGF), and CD31.ConclusionsA KGF-2/FGF-21 poloxamer hydrogel accelerated wound healing of scalded skin in GK rats, which was attributed to a synergistic effect of KGF-2-mediated cellular proliferation and FGF-21-mediated inhibition of inflammatory responses. Taken together, our findings provide a novel and potentially important insight into improving wound healing in patients with diabetic ulcers.

Beneficial effects of combination therapy of canagliflozin and teneligliptin on diabetic polyneuropathy and β-cell volume density in spontaneously type 2 diabetic Goto-Kakizaki rats

AimsParasympathetic nerve (PN) signaling plays a crucial role in the maintenance of pancreatic β-cell volume density (Vβ). PN may be pathologically affected in diabetic polyneuropathy (DPN). However, the association between the reduction of PNs in islets and Vβ and the therapeutic effects of a DPP4 inhibitor (DPP4i) and an SGLT2 inhibitor (SGLT2i) in nonobese type 2 diabetes mellitus (T2DM) Goto-Kakizaki rats (GK) have not been investigated. Materials and methodsWe divided 5-week old male GK and Wistar rats (W) into a DPP4i-treated group (GKTe), SGLT2i-treated group (GKCa), and combination-treated group (GKCaTe). After 25 weeks, the pancreata was pathologically evaluated. ResultsVβ in GK was significantly decreased (p < 0.01 vs. W), whereas Vβ was the most well preserved in GKCaTe (p < 0.05 vs. GKTe), followed by GKTe (p < 0.05 vs. GK). The decreased amount of PNs in the islets and intraepidermal nerve fiber density (IENFD) in GK was significantly improved in the treated groups compared with GK (p < 0.05 vs. GKCa and GKTe and p < 0.01 vs. GKCaTe). PN density and IENFD were significantly correlated with Vβ (r = 0.55, p < 0.01 and r = 0.54, p < 0.01, respectively). IENFD was identified as a surrogate marker for the prediction of Vβ (cutoff value, 16.39). ConclusionsThe combination therapy of DPP4i and SGLT2i improved Vβ accompanied by PNs density and IENFD. IENFD was proportionally correlated with Vβ. Therefore, the prevention of DPN development may be concurrently beneficial for the preservation of Vβ in nonobese T2DM.

Resveratrol ameliorates inflammatory and oxidative stress in type 2 diabetic Goto-Kakizaki rats

Type 2 diabetes is associated with inflammatory and oxidative stress. Resveratrol, a naturally occurring diphenolic compound, was shown to improve glycemic control and alleviate metabolic disturbances in Goto-Kakizaki (GK) rats, a non-obese model of type 2 diabetes. However, in GK rats effects of resveratrol addressing inflammatory and oxidative stress were not explored. The present study aimed to determine anti-inflammatory and anti-oxidative properties of resveratrol in these rats. GK and Sprague-Dawley (SD) rats were divided into 4 groups: GK control, GK treated with resveratrol, SD control and SD treated with resveratrol. Resveratrol (20 mg/kg b.w.) was given once a day for 10 weeks. It was shown that contents of inflammatory markers, interleukin 6 (IL-6), interleukin 1 β (IL-1β), tumor necrosis factor α (TNF-α) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), were increased in the skeletal muscle of diabetic rats, but these effects were prevented by resveratrol therapy. Similarly, amounts of IL-1β and TNF-α were elevated in livers of GK rats; however, this rise was alleviated in resveratrol-treated animals. Moreover, the contents of inflammation-related factors (IL-6, IL-1β, TNF-α and NF-κB) were augmented in adipose tissue of GK rats; nevertheless, in this tissue resveratrol was ineffective. Resveratrol reduced also lipid peroxidation in the skeletal muscle, reduced activities of glutathione peroxidase in blood serum and catalase in the livers of GK rats. Our new findings show that resveratrol therapy results in relieving inflammatory and oxidative stress in GK rats, which may be largely associated with the alleviation of metabolic disturbances in this model of diabetes. Nevertheless, it was demonstrated that the efficacy of resveratrol action is tissue-specific.

Comprehensive analysis of long non-coding RNAs and mRNAs in skeletal muscle of diabetic Goto-Kakizaki rats during the early stage of type 2 diabetes.

Skeletal muscle long non-coding RNAs (lncRNAs) were reported to be involved in the development of type 2 diabetes (T2D). However, little is known about the mechanism of skeletal muscle lncRNAs on hyperglycemia of diabetic Goto-Kakizaki (GK) rats at the age of 3 and 4 weeks. To elucidate this, we used RNA-sequencing to profile the skeletal muscle transcriptomes including lncRNAs and mRNAs, in diabetic GK and control Wistar rats at the age of 3 and 4 weeks. In total, there were 438 differentially expressed mRNAs (DEGs) and 401 differentially expressed lncRNAs (DELs) in skeletal muscle of 3-week-old GK rats compared with age-matched Wistar rats, and 1000 DEGs and 726 DELs between GK rats and Wistar rats at 4 weeks of age. The protein–protein interaction analysis of overlapping DEGs between 3 and 4 weeks, the correlation analysis of DELs and DEGs, as well as the prediction of target DEGs of DELs showed that these DEGs (Pdk4, Stc2, Il15, Fbxw7 and Ucp3) might play key roles in hyperglycemia, glucose intolerance, and increased fatty acid oxidation. Considering the corresponding co-expressed DELs with high correlation coefficients or targeted DELs of these DEGs, our study indicated that these dysregulated lncRNA-mRNA pairs (NONRATG017315.2-Pdk4, NONRATG003318.2-Stc2, NONRATG011882.2-Il15, NONRATG013497.2-Fbxw7, MSTRG.1662-Ucp3) might be related to above biological processes in GK rats at the age of 3 and 4 weeks. Our study could provide more comprehensive knowledge of mRNAs and lncRNAs in skeletal muscle of GK rats at 3 and 4 weeks of age. And our study may provide deeper understanding of the underlying mechanism in T2D of GK rats at the age of 3 and 4 weeks.

GSTO1 regulates insulin biosynthesis in pancreatic β cells

Insulin biosynthesis and secretion by pancreatic β cells are critical for the maintenance of blood glucose homeostasis. Here, we show that the expression of glutathione S-transferase omega-1 (GSTO1) is upregulated in the primary islet cells of diabetic Goto-Kakizaki (GK) rats. Knocking out GSTO1 upregulated insulin transcripts and increased the insulin content in both INS-1 cells and primary islet cells. In contrast, overexpression of GSTO1 reduced the insulin content. Furthermore, knocking out GSTO1 increased the expression of pancreatic duodenal homeobox-1 (PDX1) at both the transcription and protein levels. These results indicate that GSTO1 may be involved in the regulation of insulin biosynthesis by modulating the transcriptional expression of PDX1.