Low-dose STZ Research Articles

Tofogliflozin and Pemafibrate Combination Therapy Prevents Nonalcoholic Steatohepatitis (NASH) Development of Novel Metabolic Syndrome–Related NASH Model Mice

Nonalcoholic steatohepatitis (NASH) is closely associated with metabolic syndrome and widely defined by the presence of steatosis with inflammation and progressive fibrosis that causes to the liver transplantation and hepatocellular carcinoma (HCC). Here, we developed a novel NASH/HCC model represented metabolic syndrome like phenotypes (obesity, hyperglycemia, and glucose intolerance), and evaluated the therapeutic potential of Tofogliflozin and Pemafibrate combination therapy on NASH development. Male C57BL/6J mice were injected multiple low dose STZ (40 mg/kg) for 5 days and fed high-fat diet (HFD). These mice revealed hyperglycemia and higher body weight gain, and glucose intolerance compared with wild type mice. In addition, novel NASH/HCC model shows sequential histological changes from fatty liver to NASH (20 weeks), and all mice developed hepatocellular carcinoma after 52-week HFD feeding. Using our NASH/HCC model, we conducted the prevention study of Tofogliflozin and Pemafibrate (mono-therapy or combination therapy) against NASH development. The combination therapy has significantly prevented body weight gain from 3 weeks after treatment and this effect was persisted throughout study. While Tofogliflozin or Pemafibrate treatment markedly decreased blood glucose and triglyceride levels, the combination therapy showed the synergistic effect compared to mono-therapy groups. Histological analysis revealed Tofogliflozin or combination therapy group markedly suppressed ER-TR7 (fibroblast) and ballooning degeneration. Furthermore, these treatment groups significantly improved NAS score (NAFLD activity score). These results suggested that Tofogliflozin/Pemafibrate combination therapy would be a beneficial for NASH/NAFLD treatment. Disclosure Y. Sasaki: Employee; Self; Kowa Company, Ltd. M. Asahiyama: Employee; Self; Kowa Company, Ltd.. Employee; Spouse/Partner; Kowa Company, Ltd.. W. Kamiya: None. J. Sakai: None. T. Kodama: Consultant; Self; Kowa Company, Ltd. T. Tanaka: Research Support; Self; Kowa Company, Ltd..

Hypolipidemic effect of Coptis chinensis and C. deltoidea on type 2 diabetes rats through SCAP/SREBP-1c signal pathway

The type 2 diabetes rat model was induced with high-sugar and high-fat diet combined with low-dose STZ. This study investigated the hypolipidemic mechanism of Coptis chinensis and C. deltoidea. After 30 days of administration, HOMA-IR and the content of TG in serum were detected, and the expressions of SCAP, SREBP-1c were tested by the method of Western blot and Real-time PCR analysis. The test results showed that both components can significantly alleviate insulin resistance and down-regulate the expressions of SREBP-1c and SCAP in liver tissue of type two diabetes mellitus. Compared with the control group, there were significant differences in relevant protein expression (P<0.05, P<0.01). This indicates that the inhibition of SREBP-1c and SCAP expressions may be the hypolipidemic mechanism of Coptidis Rhizoma on type 2 diabetes mellitus. The results also showed that C. deltoidea has a better efficacy in lipid elimination, but a weaker hypoglycemic effect against C. chinensis.

Antidiabetic Effects of the Auricularia auricular Polysaccharides Simulated Hydrolysates in Experimental Type-2 Diabetic Rats

A model of type-2 diabetes mellitus (T2DM) using high-fat diet and low-dose STZ was established to assess the antidiabetic effects of Auricularia auricular polysaccharides simulated hydrolysates (AAPHs) obtained from the dried fruiting body of A. auricular. AAPHs were administered intragastrically (i.g.) at the dose of 0.15 g/kg b. W. to diabetic Wistar rats for 4 weeks. Results show that AAPHs was demonstrated to exhibit significant diminution in T-CHO and LDL-C levels (P &lt; 0.05 or P &lt; 0.01) compared to the diabetic control group. In addition, the secretion level of GLP-1 were different with the diabetes model group from 0 to 30 min, and had a tendency to alleviate weight loss. The current study suggests that AAPHs might be incorporated as a supplement in diabetic agents or combined with other health-care foods.

Abstract WP421: Remote Ischemic Injury Mediates Hippocampal Astrocytic Endfeet Remodeling, Increases Vascular Injury and Worsens Cognitive Deficits in Diabetes

Diabetes increases the risk and severity of cognitive impairment, especially after ischemic stroke. We showed pathological rearrangement of cerebrovascular networks in the cortex and striatum is associated with poor neuronal restoration leading to worsened cognitive deficits in diabetes. However, little is known about the effect of diabetes on vascular architecture of hippocampus, a domain critical to memory and learning. We hypothesized that diabetes would mediate vasoneuronal remodeling and exacerbate post-stroke deficits in hippocampal tasks. Diabetes was induced by a high fat diet and low dose STZ in male Wistar rats. Cognition was assessed for 2 weeks after stroke (90-min middle cerebral artery occlusion MCAO) by Novel Object Recognition (NOR) and Placement (NPR), Y-Maze and Social Recognition tests. Vasoneuronal architecture and integrity were assessed by measurement of surface area, branch density, IgG extravasation, neuron counts and aquaporin4 (AQP4) polarity for astrocytic endfeet remodeling in dentate gyrus. Diabetes alone increased BBB permeability and unpolarized AQP4, which were exacerbated after MCAO. Post-stroke branch density was higher in control but lower in diabetic rats. While lower baseline hippocampal neuron counts in diabetes was not further reduced after MCAO, poor baseline cognitive and social performance deteriorated. These results suggest that remote ischemic injury can induce profound vasoglial remodeling in the hippocampus and worsens functional outcomes without reducing neurons. Understanding how diabetes impacts post-stroke neurovascular recovery in hippocampus may provide critical insight to worsened cognitive outcomes in this population.

Effect Artificial Rice Diet Administration to Coronary Artery Histopathology of Rat Model Type 2 DM

The most common macrovascular complication of type 2 DM’s patiens is coronary artery disease caused by coronary artery stricture or spasm or both of them. The atherosclerosis process in coronary artery can be seen through coronary artery histopathology of rat. DM can be controlled so that the complication can be prevented, for example by controlling diet. Artificial rice with high fiber is one of breakthrough for DM patients diet. The purpose of this research is to know about the effects of artificial rice diet administration to coronary artery histopathology of rat model type 2 DM. Rats are divided to four groups consist of control normal group given standart feeding, PBA1;PBA2;PBB group are inducted by high fat diet and low dose STZ so that they become rat model type 2 DM. Since PBA1 is feeded by formula 1 artificial rice, PBA1 is feeded by formula 2 artificial rice and PBB is feeded by common rice. Rats are terminated and their hearts are taken away to make histopathology object and their coronary artery are seen under light microscope. Histopathology images are based on foam cell formed. Kruskal-Wallis’s result shows that p= 0,046 (p&lt;0,05), so that there is a significant difference between groups.Keywords : DM, atherosclerosis, foam cell, coronary artery histopathology

Therapeutic potential of genistein in ovariectomy-induced pancreatic injury in diabetic rats: The regulation of MAPK pathway and apoptosis.

Objective(s):Genistein, as a phytoestrogen found in legumes, has several biological activities in general and anti-diabetic activity particularly. In this study, we investigated the effect of genistein on proteins involved in β-cell proliferation, survival and apoptosis to further reveal its anti-diabetic potential in the ovariectomized diabetic rat.Materials and Methods:We used three-month-old female Wistar rats that either underwent ovariectomy (OVX) or received a sham surgery (Sham). In a subsequent series of experiments, OVX rats received high-fat diet and low dose STZ to induce diabetes (OVX.D) and genistein treatment (OVX.D.G). Western blot analysis was used for the assessment of phosphorylation of ERK1/2 and AKT and expression of Bcl-2 and caspase-3 in pancreas tissue. Hematoxylin-Eosin (H&E) staining was used for histopathological assessment.Results:Genistein induced AKT and ERK1/2 phosphorylation protein expression of Bcl-2 in the pancreas. In addition, genistein suppressed protein level of caspase-3. Administration of genistein significantly improved hyperglycemia in ovariectomized diabetic rat, concomitant with improved islet β-cell morphology and mass.Conclusion:These findings suggest that the beneficial antidiabetic effect of genistein partially mediated by directly modulating pancreatic β-cell function via activation of the AKT, ERK1/2, and Bcl-2, as cell survival and anti-apoptotic factors, and decreasing of proapoptotic caspase-3.

Analysis of serum undercarboxylated osteocalcin level in rats with type 2 diabetes mellitus and the correlation with cognitive impairment.

The aim of the study was to investigate the correlation between the serum undercarboxylated osteocalcin (ucOC) level and the blood biochemistry and cognitive impairment in rats with type 2 diabetes mellitus (T2DM). Sprague-Dawley (SD) rats were randomly divided into the normal control group (NC) and type 2 DM group. DM group received the high-fat and high-sugar diet combined with the intraperitoneal injection of low-dose STZ to establish the type 2 DM rat model. After 12 weeks of feeding, a Morris water maze was used to observe the rats' cognitive ability, and the levels of blood lipid, ucOC, insulin and adiponectin in the two groups were measured. The results showed that blood glucose of rats in DM group was increased significantly at 2–12 weeks (p<0.01) and the body weight was significantly increased at 4–12 weeks (p<0.01). The levels of serum triglyceride (TG), total cholesterol, low-density lipoprotein and insulin in rats in DM group were significantly increased compared with those in NC group (p<0.01) and the levels of high-density lipoprotein, adiponectin and ucOC were significantly decreased compared with those in the NC group (p<0.01). The place navigation and spatial exploration capacities of rats in DM group were significantly decreased compared with those in NC group (p<0.01). In the DM group, the place navigation and spatial exploration capacities of rats in the low ucOC group were significantly decreased compared with those in the high ucOC group (p<0.01). Additionally, single-factor correlation analysis revealed that ucOC was negatively correlated with blood glucose, TG and escape latency (p<0.01), but was positively correlated with adiponectin, residence time in target quadrant and traversing times (p<0.05 or p<0.01). In conclusion, the decreased serum ucOC level in rats with type 2 diabetes mellitus has a certain correlation with cognitive impairment.

Cichoric acid improved hyperglycaemia and restored muscle injury via activating antioxidant response in MLD-STZ-induced diabetic mice

Cichoric acid (CA), extracted from edible plants and vegetables, is a potential natural nutraceutical, with antioxidant and hypoglycaemic biological functions. The objective of this study was to explore the potential underlying molecular mechanisms involved in normalizing diabetes-related changes in hyperglycaemia via pancreas apoptosis and muscle injury induced by multiple low-dose STZ (MLD-STZ) injection in response to dietary supplementation with CA. To induce the MLD-STZ diabetic mice, the C57BL/6J mice were intraperitoneally injected with STZ (50 mg/kg body weight) for consecutive five days. CA (60 mg/kg/d) was supplemented in drinking water for 4 weeks. Compared with control, CA inhibited pancreas apoptosis and adjusted islet function in diabetic mice, leading to an increase in insulin generation and secretion. Moreover, CA regulated mitochondrial biogenesis, glycogen synthesis, and inhibited inflammation via activating antioxidant responses, which contributes to the improvement in athletic ability and diabetic myopathy. In general, CA is a natural food-derived compound with the potential application for regulating glucose homeostasis and improving diabetes and its complications.

A new method to evaluate the dose-effect relationship of a TCM formula Gegen Qinlian Decoction: "Focus" mode of integrated biomarkers.

It is difficult to accurately evaluate the efficacy of traditional Chinese medicine (TCM), which leads to the uncertainty and complexity of dose-effect analysis. In this study we established the "Focus" mode of biomarkers to characterize the dose-effect relationship of Gegen Qinlian Decoction (GQD), a TCM formula for treating type 2 diabetes mellitus (2-DM). A rat model of 2-DM was established through high fat diet feeding combined with low-dose STZ injection. Rats with 2-DM were administered high, middle or low doses (6.785, 4.071, 1.357 mg·kg-1·d-1, respectively) of GQD extract for 60 d. Metformin (300 mg·kg-1·d-1) was taken as the positive control. Blood samples were collected to assess serum biochemical indexes and metabolic profiling. After "Focus" analysis, the biochemical index triglycerides (TG) and insulin sensitivity (ISI) were identified as focused integrated biomarkers (FIBs), while arachidonic acid and docosatetraenoic acid were the metabolic FIBs. Dose-effect relationship curves of GQD were built based on these types of FIBs. Furthermore, the two dose-effect relationship curves showed similar trends with the middle dosage displaying the greatest efficacy, suggesting that insulin function and arachidonic acid metabolism played important roles in 2-DM and the responses to GQD. The metabolic FIB docosatetraenoic should be further explored for understanding its involvement in the process of 2-DM occurrence and the treatment. This "Focus" mode provides a novel strategy to evaluate the dose-effect relationship of a TCM. The system and concepts established here may also be applicable for assessing the dose-effect relationships of Western medicines.

Aldose Reductase Inhibitiory Effect of Gymnemic Acid, Trigonelline and Ferulic Acid- An In Silico Approach

Diabetic retinopathy (DR) is one of the earliest complications of chronic hyperglycemia and is a major cause of vision loss. Nearly all patients with type 1 diabetes mellitus and more than 60 % with chronic type 2 diabetes develop some degree of retinopathy after 10 years. Aldose reductase, the first enzyme in polyol pathway chiefly contributes to the development of diabetic retinopathy and other secondary complications. None of the currently available drugs used to inhibit the activity of aldose reductase is found to be ideal due to their adverse effects. Hence, the screening and identification of more effective and safer aldose reductase inhibitors from natural products have been critical requirement in the management and treatment of T2DM. Recently, we have reported the antidiabetic properties of phytochemicals such as Gymnemic acid, Trigonelline and Ferulic acid in high fat diet fed- low dose STZ induced experimental type 2 diabetes in rats. In the present study, the structure based computational method was employed to identify the in silico inhibitory effect of the above phytoingredients on aldose reductase activity. Auto Dock 4.2 is used to study the molecular interactions between the ligands and the receptor. The data obtained evidenced that the docking efficacy of the antidiabetic ligands which are comparable with fidarestat, the standard used in the present study. Thus, the antidiabetic properties of the above lead molecules may attribute to its aldose reductase inhibitory effect.

Antidiabetic Effect of Fresh Nopal (Opuntia ficus-indica) in Low-Dose Streptozotocin-Induced Diabetic Rats Fed a High-Fat Diet.

The objective of the present study was to evaluate α-glucosidase inhibitory and antidiabetic effects of Nopal water extract (NPWE) and Nopal dry power (NADP) in low-dose streptozotocin- (STZ-) induced diabetic rats fed a high-fat diet (HFD). The type 2 diabetic rat model was induced by HFD and low-dose STZ. The rats were divided into four groups as follows: (1) nondiabetic rats fed a regular diet (RD-Control); (2) low-dose STZ-induced diabetic rats fed HFD (HF-STZ-Control); (3) low-dose STZ-induced diabetic rats fed HFD and supplemented with NPWE (100 mg/kg body weight, HF-STZ-NPWE); and (4) low-dose STZ-induced diabetic rats fed HFD and supplemented with comparison medication (rosiglitazone, 10 mg/kg, body weight, HF-STZ-Rosiglitazone). In results, NPWE and NADP had IC50 values of 67.33 and 86.68 μg/mL, both of which exhibit inhibitory activities but lower than that of acarbose (38.05 μg/mL) while NPWE group significantly decreased blood glucose levels compared to control and NPDP group on glucose tolerance in the high-fat diet fed rats model (P < 0.05). Also, the blood glucose levels of HR-STZ-NPWE group were significantly lower (P < 0.05) than HR-STZ-Control group on low-dose STZ-induced diabetic rats fed HFD. Based on these findings, we suggested that NPWE could be considered for the prevention and/or treatment of blood glucose and a potential use as a dietary supplement.

Comparison of the response using ICR mice derived from three different sources to multiple low-dose streptozotocin-induced diabetes mellitus

This study was conducted to compare the multiple low-dose streptozotocin (MLDS)-induced diabetic patterns of Korl:ICR, A:ICR, and B:ICR mice obtained from three different sources. Six-week-old male ICR mice were obtained from three difference sources. Korl:ICR mice were kindly provided by the National Institute of Food and Drug Safety Evaluation (NIFDS). The other two groups of ICR mice were purchased from different vendors located in the United States (A:ICR) and Japan (B:ICR). All ICR mice that received MLDS exhibited overt diabetic symptoms throughout the study, and the incidence and development of diabetes mellitus were similar among the three ICR groups. The diabetic mice exhibited hyperglycemia, loss of body weight gain, decreased plasma insulin levels, impaired glucose tolerance, decreased number of insulin-positive cells, and decreased size of β-cells in the pancreas. The diabetes symptoms increased as the blood glucose level increased in the three ICR groups. In particular, the level of blood glucose in the STZ-treated group was higher in Korl:ICR and A:ICR mice than in B:ICR mice. The plasma insulin levels, glucose tolerance, blood chemistry, and morphological appearance of the pancreas were very similar in the ICR groups obtained from the three different sources. In conclusion, our results suggest that Korl:ICR, A:ICR, and B:ICR mice from different sources had similar overall responses to multiple low-dose STZ to induce diabetes mellitus.

Effect of protein intervention on amino acid metabolism spectrum of Qi and Yin deficiency type 2 diabetic rats

To study the effect of plant protein and animal protein on amino acid metabolism spectrum of Qi and Yin deficiency type 2 diabetic rats. 110 male SD rats were randomly divided into blank group (n=10), diabetic model group (n=20), disease-symptoms group (n=80). The rats of blank group received ordinary feeding, while other groups were fed with high sugar and fat diets. During the whole process of feeding, rats of disease-symptoms group were given with Qingpi-Fuzi (15.75 g•kg⁻¹) once a day through oral administration. Five weeks later, the rats were given with a low dose of STZ (40 mg•kg⁻¹) by intraperitoneal injection to establish experimental diabetic models. Then the models were randomly divided into disease-symptoms group 1 (Qi and Yin deficiency diabetic group, 15.75 g•kg⁻¹), disease-symptoms group 2 (plant protein group, 0.5 g•kg⁻¹), disease-symptoms group 3 (animal protein group, 0.5 g•kg⁻¹), disease-symptoms group 4 (berberine group, 0.1 g•kg⁻¹). The drugs were given for 4 weeks by gavage administration. After 4 weeks of protein intervention, the abdominal aortic blood was collected and serum was isolated to analyze its free amino acid by using AQC pre-column derivatization HPLC and fluorescence detector. Four weeks after the protein intervention, plant protein, animal protein and berberine had no obvious effect on body weight and blood sugar in type 2 diabetic rats. As compared with animal protein group, histidine and proline（P<0.01）, serine, glycine, threonine, alanine, tyrosine, valine, methionine, bright+isoleucine, phenylalanine and lysine（P<0.05）changed a lot in rats serum of plant protein group.The results showed that gavage administration of protein would produce effects on amino acid metabolism of Qi and Yin deficiency type 2 diabetic SD rats. Symbolic differential compounds could be found through metabonomics technology, providing experimental basis for early warning of type 2 diabetes and diagnosis of Qi and Yin deficiency syndrome.

Abstract 279: Stromal Cell-derived Factor-1 Prevents From Diabetic Cardiomyopathy via Cxcr7/ampk-mediated Nrf2 Activation in Type 2 Diabetic Mice

We have demonstrated that stromal cell-derived factor 1(SDF-1) protects against palmitate-induced cardiac cell death via CXCR7-mediated activation of AMPK signaling (Diabetes 62:2545-2558, 2013). Whether SDF-1 prevents diabetic cardiomyopathy (DCM) and what the underlying mechanism has not been addressed. Here we evaluated the prevention of SDF-1 from DCM in a high fat diet plus streptozotocin (HFD/STZ)-induced type 2 diabetic model in C57BL/6J mice. After 1 month on HFD, the HFD-fed mice were injected with one low dose STZ (100mg/kg body weight, ip). Five days after STZ injection, mice with blood glucose levels ≥250 mg/dl were defined as diabetic. In parallel, the age-matched normal diet-fed mice injected with a same volume of vehicle were used as control. After onset of diabetes, the mice were maintained on HFD or normal diet for another 4 months with or without SDF-1 treatment. Then cardiac function was assayed again, and the mice were sacrificed and cardiac tissue collected for cardiomyopathic index assay. We found that 1 month HFD feeding induced a significant insulin resistance without effect on cardiac function, but continued HFD feeding after STZ injection significantly increased insulin resistance and blood glucose, as well as blood insulin, triglyceride and cholesterol levels. Furthermore, HFD/STZT significantly impaired cardiac function, which were accompanied by increased cardiac inflammation, oxidative stress and fibrotic remodeling. Treatment with SDF-1 dose-dependently prevented diabetes-induced cardiac dysfunction, inflammation and remodeling, but without significant effects on the above mentioned other pathophysiological changes. Mechanistic study demonstrated that diabetes significantly inhibited the function of AMPK and Nrf2, and the expression of CXCR7, but not CXCR4; while treatment with SDF-1 significantly preserved AMPK and Nrf2 function and CXCR7 expression. Knockout CXCR4 did not affect SDF-1 preservation of AMPK and Nrf2 function, but SiRNA knockdown of AMPK resulted in blockade of SDF-1 preservation of Nrf2 function. These results indicate that SDF-1 prevents from DCM via CXCR7/AMPK-mediated Nrf2 activation in type 2 diabetic mice.

Left ventricular deformation associated with cardiomyocyte Ca(2+) transients delay in early stage of low-dose of STZ and high-fat diet induced type 2 diabetic rats.

BackgroundIn the early stage of diabetes, the cardiac ejection fraction is preserved, despite the existence of the subclinical cardiac dysfunction to some extent. However, the detailed phenotype of this dysfunction and the underlying mechanism remain unclear. To improve our understanding of this issue, we used low-dose STZ and high-fat diet to induce type 2 diabetic models in rats. The effects and the mechanism associated with the early stages of the disease were analyzed.MethodsThe type 2 diabetic mellitus (T2DM) in SD rats were induced through 30 mg/kg STZ and high-fat diet. Two-dimensional spackle-tracking echocardiography (STE) and the dobutamine test were performed to examine the cardiac function. Calcium transients of left ventricular myocytes were detected and the related intracellular signalling factors were analyzed by western blotting.ResultsAfter 6-weeks, T2DM rats in left ventricular (LV) diastole showed decreased global and segment strain(S) levels (P < 0.05), both in the radial and circumferential directions. Strain rate (Sr) abatement occurred in three segments in the radial and circumferential directions (P < 0.05), and the radial global Sr also decreased (P < 0.05). In the systolic LV, radial Sr was reduced, except the segment of the anterior septum, and the Sr of the lateral wall and post septum decreased in the circumferential direction (P < 0.05). Conventional M-mode echocardiography failed to detect significant alterations of cardiac performance between the two groups even after 12 weeks, and the decreased ejection fraction (EF%), fractional shortening (FS%) and end-systolic diameters (ESD) could be detected only under stress conditions induced by dobutamine (P < 0.05). In terms of calcium transients in cardiac myocytes, the Tpeak in model rats at 6 weeks was not affected, while the Tdecay1/2 was higher than that of the controls (P < 0.05), and both showed a dose-dependent delay after isoproterenol treatment (P < 0.05). Western blot analysis showed that in 6-week T2DM rats, myocardial p-PLB expression was elevated, whereas p-CaMKII, p-AMPK and Sirt1 were significantly down-regulated (P < 0.05).ConclusionA rat model of T2DM was established by low dose STZ and a high-fat diet. LV deformation was observed in the early stages of T2DM in association with the delay of Ca2+ transients in cardiomyocytes due to the decreased phosphorylation of CaMKII. Myocardial metabolism remodeling might contribute to the early LV function and calcium transportation abnormalities.

Effect and mechanism of polydatin on diabetic myocardial hypertrophy in mice

To observe the preventive effect of polydatin on diabetic myocardial hypertrophy in mice and discuss its and mechanism. The diabetic model was induced with low dose STZ (40 mg x kg(-1) x d(-1) x 5 d, ip) for five days in mice. The myocardial hypertrophy was determined by hypertrophy indexes (LVHI, left ventricular/right ventricle and septum), left ventricular/body weight (LV/BW), the histological examination and the mRNA expression of atrial natriuretic factor(ANF). The fast blood glucose(FBG), serum insulin and plasma hemoglobin A1c ( HbA1c) levels were detected, and then HOMA insulin resistance index ( HOMA. IR) was calculated. The mRNA and protein expressions were measured by qRT-PCR and western blotting, respectively. According to the results, the FBG of the model group exceeded 11.1 mmol x L(-1), with notable decrease in BW and significant increase in insulin, HbA1c and HOME. IR, suggesting the successful establishment and stability of the diabetic model. The increases in LVHI, LV/BW, cell surface and ANF mRNA indicated a myocardial hypertrophy in diabetic mice. Meanwhile, the model group showed decrease in mRNA and protein expressions of PPARβ and significant increase in NF-κB p65, COX-2 and iNOS expressions. After the preventation with PD (50, 100 mg x kg(-1) x d(-1)), diabetic mice showed increase in BW, reduction in the levels of FBG, insulin and HbA1 c, relief in insulin resistance and significant recovery in hypertrophy indexes, indicating PD has the protective effect in diabetic myocardial hypertrophy. Meanwhile, PD up-regulated the expression of PPARβ, inhibited the expressions of NF-κB p65, COX-2 and iNOS, demonstrating that PD's protective effect may be related to the activation of PPARβ and the inhibition of NF-κB, COX-2 and iNOS signaling pathways.

Abstract 315: Stromal Cell-derived Factor 1 Protects From Diabetic Cardiomyopathy

We have demonstrated that stromal cell-derived factor 1(SDF-1) protects against palmitate-induced cardiac apoptosis, which is mediated by NOX-activated nitrosative damage and endoplasmic reticulum stress, via CXCR7, to activate AMPK/p38 MAPK-mediated IL-6 generation (Diabetes 62:2545-2558, 2013). Whether SDF-1 prevents diabetic cardiomyopathy has not been addressed. Here we evaluated the preventive effects of SDF-1 from diabetic cardiomyopathy in a high fat diet plus streptozotocin (HFD/STZ)-induced type 2 diabetic model in C57BL/6J mice. After 1 month on HFD, cardiac function was assayed by echocardiography, and then HFD-fed mice were injected with one low dose STZ (100mg/kg body weight, ip). Five days after STZ injection, mice with blood glucose levels ≥250 mg/dl were defined as diabetic. In parallel, the age-matched normal diet-fed mice injected with a same volume of citrate buffer (pH4.5) were used as control. After onset of diabetes, the mice were maintained on HFD or normal diet for another 4 months with or without SDF-1 treatment. Then cardiac function was assayed again, and the mice were sacrificed and cardiac tissue collected for cardiomyopathic index assay. We found that 1 month HFD feeding induced a significant insulin resistance without effect on cardiac function, but continued HFD feeding after STZ injection significantly impaired cardiac function, which were accompanied by increased insulin resistance and blood glucose, as well as blood insulin, triglyceride and cholesterol levels. Treatment with SDF-1 dose-dependently prevented diabetes-induced cardiac dysfunction but without significant effects on the above mentioned other pathophysiological parameters. These results indicate that SDF-1 possibly prevents diabetic cardiomyopathy via a direct cardiomyocyte action, which needs to be further defined in future study.

Antioxidant Effect of Aqueous Extract of Triticum aestivum Grass on Insulin Resistance models in Wistar Albino Rats

Context: Prolonged use of hypoglycaemic drugs is problematic due to their toxic side effects and diminution of response. Oral antihyperglycaemic agents from plant sources are therefore being explored for use in traditional medicine. Aims: To study antihyperglycaemic, hypolipidemic and antioxidant effect of aqueous extract of Triticum aestivum grass (TAGE) in two different models of T2DM in wistar albino rats such as High Fat Diet with Low dose STZ and High Fructose Diet models. Settings and Design: Two models of insulin resistance were used (single i.p injection of STZ (45 mg/kg) with high fat diet and fructose 10% w/v, p.o, ad libitum). Methods and Material: STZ with high fat diet and fructose 10% w/v, p.o, in rats was administered for a period of 21 days. Three doses of TAGE (40, 60 and 80 mg/kg, p.o) were used. Pioglitazone (PG) 20 mg/kg was used as the reference standard. At the end of the experimental period, serum biochemical parameters like fasting blood sugar, plasma insulin, lipid profile and MDA and SOD activity were studied in both the models. Statistical analysis used: one way ANOVA followed by Turkey’s multiple comparison test. p&lt;0.05 was considered as significant. Results: In both the models, TAGE significantly lowered plasma glucose, lipid, MDA level and increased SOD activity. It also improved insulin resistance which is comparable to that of normal and standard group. Conclusion: TAGE may be a potent drug, for treatment and prevention of complications of T2DM used alone or in combination with other oral hypoglycaemic agents.

High-fat diet combined with low-dose streptozotocin injections induces metabolic syndrome in Macaca mulatta.

Metabolic syndrome (MetS) is associated with abdominal obesity, hyperlipidemia, insulin resistance, and type 2 diabetes mellitus, and increases the risk of cardiovascular disease. Given the complex multifactorial pathogenesis of MetS, qualified animal models are currently seriously limited for researchers. The aim of our study was to develop a MetS model in juvenile rhesus monkeys (Macaca mulatta). Rhesus monkeys (1-year-old) fed a high-fat diet (15 % fat, 2 % cholesterol) were used as the HF group (n = 6), and those on a normal diet (5 % fat) were used as the control group (n = 4). After being fed a high-fat diet for approximately 12 months, 2 monkeys (HF + STZ group) were injected with low-dose streptozotocin (STZ, 25 mg/kg) twice, with a 7 days interval, and were then fed the same diet continuously for another 24 months. After 36 months of treatment, the high-fat diet monkeys, including the HF and HF + STZ groups, had acquired increased body weights, abnormal serum lipids, and impaired glucose tolerance compared to the control group. In addition, much more marked metabolic changes were observed in the two monkeys of the HF + STZ group, particularly in terms of high-blood glucose level and insulin resistance. Morphological observation of biopsies of liver and pancreatic tissues showed decreased islet number and mass and decreased insulin staining in the monkeys of the HF + STZ group. In addition, Oil red O staining suggested remarkable accumulation of lipid droplets in the hepatocytes. Our study suggested that a long-term high-fat diet followed with a low-dose STZ was able to induce MetS in juvenile rhesus monkeys with faster pathophysiological progress compared with high-fat diet induction alone. Our primary data showed that this method may have potentials to develop MetS animal model in non-human primates.

Peribiliary glands as a niche of extra-pancreatic insulin- producing cells during experimental diabetes

Glands of biliary tree (Peribiliary Glands: PBGs) contain a niche of heterogeneous endodermal-like stem/progenitors cells (Biliary Tree Stem/progenitor Cells: BTSCs) that can be easily induced to differentiate, in vitro and in vivo, towards pancreatic islets (1,2). Whether these cells may play a role in insulin production in diabetes is unknown. The aim of this study was to evaluate, in experimental diabetes, proliferation of PBGs and differentiation of BTSCs towards insulin-producing cells. Diabetes was generated in mice by intraperitoneal injection of a single dose of 200 mg/kg (High-Dose STZ group; N=12) or 120 mg/kg of STZ (Low-Dose STZ group; N=12). Control mice (N=17) were injected with citrate buffer (i.e. the STZ carrier). Glucose levels in blood and urine and HbA1c blood levels were measured. Liver, pancreas and extrahepatic biliary trees (EHBT) were en bloc microdissected and processed for histology, immunohistochemistry, immunofluorescence, and RT-PCR. Our results showed that PBGs proliferated in an experimental model of type-1 diabe- tes. Their proliferation was greatest at the hepato-pancreatic ampulla and correlated with a decreased pancreatic islets’ mass. The PBG proliferation was characterized by the expansion of the compartment of Sox9+ stem/progenitor cells that gave rise to insulin-producing cells. Insulin-producing cells were mostly located in the portion of EHBT closest to the duodenum, and their appearance was associated with the upregulation of MafA and Gli1 gene expression. PBG proliferation and the expansion of Sox-9+, insulin-producing cells were more evident after 90 than after 30 days STZ treatment. In conclusion, PBGs and associated BTSCs respond to diabetes with proliferation and differentiation towards insulin-producing cells. This indicates that PBG niche may rescue the pancreatic islet impairment in diabetes with important implications for the patho-physiology and complications of this disease.