Type 2 Diabetes Mellitus Rat Model Research Articles

Role of Proximal Intestinal Glucose Sensing and Metabolism in the Blood Glucose Control in Type 2 Diabetic Rats After Duodenal Jejunal Bypass Surgery.

Although gastric surgery can significantly improve blood glucose homeostasis in type 2 diabetes mellitus (T2DM), its mechanism remains unclear. This study evaluated the role of intestinal glucose sensing, glucose transport, and metabolism in the alimentary limb (A limb) of T2DM rats after duodenal jejunal bypass (DJB) surgery. A T2DM rat model was induced via a high-glucose high-fat diet and low-dose streptozotocin injection. The diabetic rats were divided into two groups: the DJB surgery (T2DM-DJB) group and the sham surgery (T2DM-Sham) group. Wistar rats were used as wild-type control (Control). Small animal PET was used to assess the change in glucose metabolic status in the intestine. The intestinal villi height and the number of EECs after DJB were evaluated. The expressions of sweet taste receptors (T1R2/T1R3), glucose transporters (SGLT1/GLUT2), and key enzymes involved in glucose metabolism (HK2, PFK2, PKM2, G6Pase, and PCK1) in the A limb after DJB was detected by Western blot and qRT-PCR. Small animal PET analysis showed the intestinal glucose metabolism increased significantly 6weeks after DJB surgery. The intestinal villi height and the number of EECs in the A limb 6weeks after surgery increased significantly in T2DM-DJB rats comparing to T2DM-Sham rats. The mRNA and protein expression of T1R1/T1R3 and SGLT1/GLUT2 were downregulated in DJB-T2DM rats, while enzymes involved in glucose metabolism was upregulated in the A limb in T2DM-DJB rats. Proximal intestinal glucose sensing and metabolism play an important role in blood glucose homeostasis by DJB.

Rise in Postprandial GLP-1 Levels After Roux-en-Y Gastric Bypass: Involvement of the Vagus Nerve-Spleen Anti-inflammatory Axis in Type 2 Diabetic Rats.

The mechanism underlying postprandial glucagon-like peptide-1 (GLP-1) changes after metabolic surgery remains mostly unclarified. This investigation aimed to address whether the vagus nerve-spleen anti-inflammatory axis is involved in the rise in postprandial GLP-1 levels in type 2 diabetes mellitus (T2DM) rats following metabolic surgery. T2DM rat model was established with a high-fat diet and a low dose of streptozotocin and subjected to Roux-en-Y gastric bypass (RYGB) and splenic denervation. A mixed-meal tolerance test for postprandial GLP-1 response was performed. TNF-α in the plasma, spleen, and ileum was measured by ELISA, and alpha 7 nicotinic acetylcholine receptor (α7nAChR) expression in the spleen was analyzed by Western blot. Postprandial GLP-1 improvement by RYGB was accompanied by the reduction of TNF-α levels in spleen and ileum and up-regulation of splenic α7nAChR in T2DM rats. Splenic denervation abrogates a rise in postprandial GLP-1 levels in response to the mixed-meal challenge, along with higher TNF-α levels in spleen and ileum and down-regulation of splenicα7nAChR, compared with denervated sham rats. Our results reveal that the vagus nerve-spleen anti-inflammatory axis mediates the rise of postprandial GLP-1 response after RYGB through lowering TNF-α contents in the intestinal tissue in T2DM rats.

Comparative Evaluation of the Effect of Metformin and Insulin on Gut Microbiota and Metabolome Profiles of Type 2 Diabetic Rats Induced by the Combination of Streptozotocin and High-Fat Diet.

Lately, an increasing number of studies have investigated the relationship between metformin and gut microbiota, suggesting that metformin exerts part of its hypoglycemic effect through the microbes. However, its underlying mechanism remains largely undetermined. In the present study, we investigated the effects of metformin on gut microbiota and metabolome profiles in serum and compared it with insulin treatment in rats with type 2 diabetes mellitus (T2DM). Diabetic rats (DM group) were induced by a combination of streptozotocin and high-fat diet (HFD). After 7 days, DM rats were treated with metformin (MET group) or insulin (INS group) for 3 weeks. The 16S rRNA sequencing of the gut microbiota and non-targeted metabolomics analysis of serum were conducted. A total of 13 bile acids (BAs) in serum were further determined and compared among different groups. The rat model of T2DM was well established with the typical diabetic symptoms, showing significantly increased blood glucose, AUC of OGTT, HOMA-IR, TC, TG, LDL-C and TBA. Metformin or insulin treatment could ameliorate symptoms of diabetes and partly recover the abnormal biochemical indicators. Compared with DM rats, the relative abundances of 13 genera were significantly changed after metformin treatment, while only three genera were changed after insulin treatment. The metformin and insulin treatments also exhibited different serum metabolome profiles in T2DM rats. Moreover, 64 differential metabolites were identified between MET and DM groups, whereas 206 were identified between INS and DM groups. Insulin treatment showed greater influence on amino acids, glycerophospholipids/glycerolipids, and acylcarnitine compared with the metformin treatment, while metformin had an important impact on BAs. Furthermore, metformin could significantly decrease the serum levels of CA, GCA, UDCA, and GUDCA, but increase the level of TLCA in DM rats. Insulin treatment significantly decreased the levels of CA, UDCA, and CDCA. Besides, several metabolites in serum or microbiota were positively or negatively correlated with some bacteria. Collectively, our findings indicated that metformin had a stronger effect on gut microbiota than insulin, while insulin treatment showed greater influence on serum metabolites, which provided novel insights into the therapeutic effects of metformin on diabetes.

Protective Effect of Cordycepin on Impairment of Endothelial Function in Type 2 Diabetes Mellitus.

Type 2 diabetes mellitus (T2DM) is a major risk factor for cardiovascular diseases. The reduction of mitochondrial protein sirtuin protein 3 (SIRT3) has been reported to contribute to the development of T2DM by impacting mitochondrial respiration. Cordycepin is an adenosine derivative and is isolated from the culture filtrate of Cordyceps militaris. This study explored the protective effect of cordycepin on vascular impairment induced by T2DM and its properties and protective mechanism. In this study, a T2DM rat model was established. The endothelium-dependent relaxation of the thoracic aorta ring decreased in T2DM rats could be reversed by cordycepin. Next, mitochondrial impairment in human umbilical vein endothelial cells was detected by JC-1 staining. In vitro studies revealed that cordycepin plays a beneficial role in advanced glycation end product-induced endothelial mitochondrial impairment. Moreover, according to the cordycepin molecular docking analysis, cordycepin can bind to SIRT3. Cordycepin increased the expression and activation of SIRT3 in a dose-dependent manner. SIRT3 interruption blocked the protective effect of cordycepin on mitochondria in human umbilical vein endothelial cells. Cordycepin can conclusively protect vascular function impaired by T2DM, and the mechanism may potentially be involved in SIRT3 signaling pathways.

In vivo therapeutic exploring for Mori folium extract against type 2 diabetes mellitus in rats.

Background: The study was aimed to investigate the potential therapeutic effect of Mori folium aqueous extracts (MFAE) on type 2 diabetes mellitus (T2DM) in vivo.Methods and results: A rat model of T2DM was established with the combination of high sugar and high-fat diet (HSFD) and streptozotocin (STZ). The T2DM rats were administrated with low (2 g.kg−1) and high (5 g.kg−1) doses of MFAE for 60 consecutive days. The biochemical indices of glucose metabolism disorders, insulin resistance and oxidative stress were observed. The results indicated that MFAE significantly promoted the synthesis of hepatic glycogen, reduced the levels of fasting blood glucose and fasting blood insulin, and improved the insulin sensitivity index (ISI). MFAE administration also remarkably increased the levels of superoxide dismutase (SOD) and reduced the levels of malondialdehyde (MDA).Conclusion: MFAE showed a therapeutic effect on T2DM with the bioative effect of improve glucose metabolism disorders, decrease insulin resistance, and ameliorate the antioxidative ability.

Untargeted metabolomics analysis of the anti-diabetic effect of Red ginseng extract in Type 2 diabetes Mellitus rats based on UHPLC-MS/MS

Red ginseng is a traditional Chinese herbal medicine that has long been used to treat diabetes, and its blood sugar-lowering activity has been confirmed. However, the mechanism of action of red ginseng on type 2 diabetes mellitus (T2DM) at the metabolic level is still unclear. The purpose of this study is to investigate the effect of red ginseng extract in the treatment of T2DM rats based on untargeted metabolomics. The rat model of T2DM was induced by a high-fat diet (HFD) combined with streptozotocin (STZ), and serum samples were collected after four weeks of treatment. The ultra-high-performance liquid chromatography coupled with Q Exactive HF-X Mass Spectrometer was used to analyze the level of metabolites in serum to evaluate the differences in metabolic levels between different groups. The results of biochemical analysis showed that red ginseng extract intervention significantly improved the levels of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), serum glucose (GLU), and fasting insulin (FINS) after four weeks. Orthogonal partial least squares discriminant analysis was used to study the overall changes of rat metabolomics. After the intervention of red ginseng extract, 50 biomarkers showed a callback trend. Metabolic pathway enrichment analysis showed that the regulated pathways were D-arginine and D-ornithine metabolism, D-glutamine and D-glutamate metabolism, taurine and hypotaurine metabolism, arginine biosynthesis, and tryptophan metabolism. Generally, the results demonstrated that red ginseng extract had beneficial effects on T2DM, which could be mediated via ameliorating the metabolic disorders.

Veratrilla baillonii Franch Ameliorates Diabetic Liver Injury by Alleviating Insulin Resistance in Rats.

Type 2 diabetes mellitus (T2DM) is a complex and polygenic disorder with diverse complications. Veratrilla baillonii Franch (V. baillonii) has been applied in the intervention and treatment a diverse range of diseases, including diabetes. In this study, we revealed that water extracts of V. baillonii (WVBF) can ameliorate liver injury and insulin resistance in T2DM rat model. To elucidate the anti-diabetic mechanisms of WVBF, we performed liver transcriptome analysis that displayed WVBF treatment significantly suppressed many gene expressions involved in insulin resistance. Furthermore, functional experiments showed that WVBF treatment reduced the pathological damages of liver and pancreas, which may be regulated by Foxo1, Sirt1, G6pc, c-Met, Irs1, Akt1, Pik3r1. These results indicated that WVBF improves diabetic liver injury and insulin resistance in diabetic rats. Therefore, this study demonstrated WVBF could be used as a promising therapeutic agent for intervention and treatment of diabetes.

Sleeve gastrectomy suppresses hepatic de novo cholesterogenesis and improves hepatic cholesterol accumulation in obese rats with type 2 diabetes mellitus

ObjectivesCholesterol metabolic disturbance increases the risk of various acquired diseases and affects public health. An apparent correlation between hypercholesterolemia and type 2 diabetes mellitus (T2DM) was confirmed recently. Bariatric surgery can induce durable and sufficient loss of body weight and T2DM remission. A previous study illustrated a cholesterol-lowering effect of sleeve gastrectomy (SG), but the intrinsic mechanism is still elusive. The present study aimed to investigate the effects of SG on hypercholesterolemia and hepatic cholesterol accumulation in a T2DM rat model. MethodsObese rats with T2DM were randomly subjected to sham operation, sham operation combined with food restriction, or SG. Body weight, food intake, blood glucose, body composition, and cholesterol level were measured at the indicated time points. Subsequently, hepatic cholesterol content and both protein and transcriptional levels of sterol regulatory element-binding protein 2, 3-hydroxy-3-methylglutaryl-coenzyme A reductase, and low-density lipoprotein receptor were measured at 2 and 4 wk postoperatively. ResultsSG rapidly reduced blood glucose independent of loss of body weight and food restriction. Rats that underwent SG exhibited lower total cholesterol and free cholesterol in both serum and liver. The cholesterol-lowering effect was independent of loss of body weight and food restriction at just 2 wk postoperatively. Protein and mRNA expression of sterol regulatory element-binding protein 2, 3-hydroxy-3-methylglutaryl-coenzyme A reductase, and low-density lipoprotein receptor were inhibited at 2 wk postoperatively and recovered by 4 wk after SG. ConclusionSG alleviated hypercholesterolemia and hepatic cholesterol accumulation partially by inhibiting hepatic de novo cholesterogenesis.

The Effect of Strawberry Juice on Homa-IR Level in Rat Model of Type 2 Diabetes Mellitus

Background: Strawberries contain high level of antioxidants and polyphenols, especially anthocyanins as powerful antioxidants. These ingredients can recover insulin resistance, oxidative stress, and pancreatic beta-cell function, which can affect blood sugar levels. This study aimed to evaluate the effect of strawberry juice in recovering insulin resistance in rat model of type 2 diabetes mellitus (T2DM) by homeostatic model assessment of insulin resistance (HOMA-IR) indicators.Methods: In an experimental study, 21 male rats (Rattus norvegicus) of Wistar strain were enrolled and received streptozotocin and nicotinamide to induce DM. They were divided into groups of P1 as negative control group in absence of any treatment, P2 as positive control group that were given metformin HCl (0.9 mg/Kg BW/day), and P3 as intervention group receiving strawberry juice (3.6 mL/200 g BW/day) for 14 days. The HOMA-IR level was determined for all groups and compared.Results: HOMA-IR level in P1 was 8.32±0.26, in P2 was 4.89±0.29, and in P3 was 5.16±0.20. Among groups, prior to treatment, there were no signifcant differences (p =0.66). A signifcant decrease was noted in HOMA-IR in P2 group (-3.75±0.09; p <0.001) and P3 group (-3.26±0.12; p <0.001), while in P1 group was not signifcant (0.03±0.12; p =0.46).Conclusion: Strawberry fruit like metformin was effective in reducing HOMA-IR in rat model of T2DM, when administered alone.

Effect of Gegen Qinlian Decoction on Hepatic Gluconeogenesis in ZDF Rats with Type 2 Diabetes Mellitus Based on the Farnesol X Receptor/Ceramide Signaling Pathway Regulating Mitochondrial Metabolism and Endoplasmic Reticulum Stress.

Background Type 2 diabetes mellitus (T2DM) is a kind of disorder of glucose and lipid metabolism with the main clinical manifestation of long‐term higher blood glucose level than the normal value. Farnesol X receptor (FXR)/ceramide signaling pathway plays an important role in regulating cholesterol metabolism, lipid homeostasis, and the absorption of fat and vitamins in diet. Gegen Qinlian Decoction (GQD) is a classical herbal formula, which has a good clinical therapeutic effect on diabetes-related metabolic syndrome. Objective To investigate the effect of Gegen Qinlian Decoction (GQD) on hepatic gluconeogenesis in obese T2DM rats based on the FXR/ceramide signaling pathway regulating mitochondrial metabolism and endoplasmic reticulum stress (ERS). Methods ZDF (fa/fa) rats were fed with high-fat diet to establish the T2DM model; GQD was given to T2DM model rats by gavage; changes of the general state and body weight of rats were recorded; fasting blood glucose was detected; blood insulin, blood ceramide, glycosylated hemoglobin in blood, acetyl CoA in liver mitochondria, and bile salt lyase in intestinal tissue were detected by ELISA. The content of T-β-MCA in blood was detected by LC-MS; the content of glycogen in liver tissue was detected by PAS staining; the expression of FXR, Sptlc2, and Smpd3 in ileum tissue, P-PERK, ATF6α, GRP78 BIP, and P-IRE1 in the liver, and CS and PC protein in liver mitochondria was detected by immunohistochemistry and western blot assay. The mRNA expression levels of FXR, Sptlc2, and Smpd3 in the ileum, PERK, ATF6α, GRP78 BIP, and IRE1 in the liver, and CS and PC in liver mitochondria were detected by qRT-PCR. Results GQD can improve the general state of T2DM rats, slow down their weight gain, reduce the levels of fasting blood glucose, fasting insulin, glycosylated hemoglobin, blood ceramide, bile salt hydrolase in intestinal tissue, and acetyl CoA in liver mitochondria of T2DM rats, and increase the contents of liver glycogen and T-β-MCA in blood of T2DM rats. At the molecular level, GQD can inhibit the expression levels of FXR, Sptlc2, and Smpd3 in the ileum of T2DM rats and the protein and mRNA expression levels of oxidative stress-related factors in the liver. At the same time, GQD can increase the expression of CS and reduce the expression of PC in liver mitochondria of T2DM rats. Conclusion GQD can inhibit the FXR/ceramide signaling pathway, regulate endoplasmic reticulum stress, enhance the CS activity of liver mitochondria, reduce the acetyl CoA level and PC activity of liver mitochondria, inhibit hepatic gluconeogenesis, protect islet β-cells, and control blood glucose.

P2. Use of semaphorin 3A for improving osseointegration of titanium implants in type 2 diabetes mellitus rats

<h3>BACKGROUND CONTEXT</h3> Type 2 diabetes mellitus (T2DM) is a systemic disease that can compromise osseointegration of metal implants; thus, technologies that can improve osteogenesis in T2DM patients are needed. Semaphorin 3A (3A) is a novel osteoprotective protein that has been reported to improve bone formation. Our goal was to assess 3A for potential clinical use. However, current T2DM rat models lack translatability to human conditions. It is important to clarify osseointegration in a more translational T2DM. For this study, we used the Zucker diabetic Sprague Dawley rat (ZDSD) as a more clinically relevant T2DM model. It is a polygenic model with an intact leptin pathway as in humans, and exhibits human-like type 2 diabetes progression. <h3>PURPOSE</h3> This study used grit blasted/acid etched (SLA) Ti implants (microrough/hydrophobic) in ZDSD rat femurs to determine if 3A can improve their osseointegration in T2DM. <h3>METHODS</h3> Thirty male, 15-week-old ZDSD rats (D, Charles River) and 24 aged-matched male Sprague Dawley rats (N, Charles River) were used (IACUC approved). Rats were paired fed with a high-fat diet (Purina 5SCA) until 70% of D rats turned diabetic (blood glucose >250mg/dL for a week) and switched to a normal diet (Purina 5008) for the rest of the study. Three weeks after turning diabetic, D rats were randomized to three groups: click hydrogel delivery vehicle (D GEL), hydrogel containing 3A (D 3A+GEL), hydrogel implanted and 3A injected separately (D i3A+GEL) with n=7. N rats were randomized to N GEL, N 3A+GEL, N i3A+GEL with n=8. Holes were created bilaterally in the metaphysis of distal femurs, and hydrogels were inserted in the hole by mixing PEG-N3 and PEG-DBCO crosslinker with either 0.9% sterile saline in GEL and i3A+GEL or with 6ug 3A in 3A+GEL. SLA implants (Institut Straumann AG) were inserted immediately into the holes after GEL. i3A+GEL had bilateral subperiosteal 3A injections (6ug/leg) at implant sites on day 3 and day 10 post-surgery. Rats were euthanized at 4 weeks postop. Bone phenotype and osseointegration of isolated fixed femurs were assessed by micro-computed tomography (microCT). Total bone to implant contact (BIC) was defined as the percentage of the implant surface in contact with newly formed bone. Evaluations of BIC were also performed separately for two subregions, the medullary (bone marrow BIC) and the cortical compartment (cortical BIC). Removal torque testing was performed with fresh, non-fixed femurs. <h3>RESULTS</h3> D GEL had less trabecular bone formation than N GEL. Cortical bones at metaphysis and mid-diaphysis were not affected by T2DM. D GEL had less total BIC and less bone marrow BIC but no difference in cortical BIC than N GEL. D 3A+GEL had less total BIC and cortical BIC than N 3A+GEL but bone marrow BIC in D 3A+GEL was the same as in N 3A+GEL. Similar results were observed between D i3A+GEL and N i3A+GEL. Maximum torque and torsional stiffness were less in D GEL than N GEL but not different between D 3A+GEL and N 3A+GEL or D i3A+GEL and N i3A+GEL. There was no significant difference in torsional energy among all groups. <h3>CONCLUSIONS</h3> T2DM reduced trabecular bone formation but did not affect cortical bone. Osseointegration was impaired in T2DM indicated by having less total BIC. Sema3A improved osseointegration in T2DM indicated by increased bone marrow BIC and increased mechanical properties of integrated bone tissues after sema3A delivered by hydrogel or local injection. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

LC-MS-Based Untargeted Metabolomics Reveals Early Biomarkers in STZ-Induced Diabetic Rats With Cognitive Impairment.

Diabetes in the elderly increases cognitive impairment, but the underlying mechanisms are still far from fully understood. A non-targeted metabolomics approach based on liquid chromatography-mass spectrometry (LC-MS) was performed to screen out the serum biomarkers of diabetic mild cognitive impairment (DMMCI) in rats. Total 48 SD rats were divided into three groups, Normal control (NC) group, high-fat diet (HFD) fed group and type 2 diabetes mellitus (T2DM) group. The T2DM rat model was induced by intraperitoneal administration of streptozotocin (STZ, 35 mg/kg) after 6 weeks of high-fat diet (HFD) feeding. Then each group was further divided into 4-week and 8-week subgroups, which were calculated from the time point of T2DM rat model establishment. The novel object recognition test (NORT) and the Morris water maze (MWM) method were used to evaluate the cognitive deficits in all groups. Compared to the NC-8w and HFD-8w groups, both NOR and MWM tests indicated significant cognitive dysfunction in the T2DM-8w group, which could be used as an animal model of DMMCI. Serum was ultimately collected from the inferior vena cava after laparotomy. Metabolic profiling analysis was conducted using ultra high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) technology. Principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) were used to verify the stability of the model. According to variable importance in the project (VIP > 1) and the p-value of t-test (P < 0.05) obtained by the OPLS-DA model, the metabolites with significant differences were screened out as potential biomarkers. In total, we identified 94 differentially expressed (44 up-regulated and 50 down-regulated) endogenous metabolites. The 10 top up-regulated and 10 top down-regulated potential biomarkers were screened according to the FDR significance. These biomarkers by pathway topology analysis were primarily involved in the metabolism of sphingolipid (SP) metabolism, tryptophan (Trp) metabolism, Glycerophospholipid (GP) metabolism, etc. Besides, SP metabolism, Trp metabolism and GP metabolism mainly belonging to the lipid metabolism showed marked perturbations over DMMCI and may contribute to the development of disease. Taken collectively, our results revealed that T2DM could cause cognitive impairment by affecting a variety of metabolic pathways especially lipid metabolism. Besides, serum PE, PC, L-Trp, and S1P may be used as the most critical biomarkers for the early diagnosis of DMMCI.

The Pattern of Peroxisome Proliferator-activated Receptor Gamma Coactivator 1-alpha Gene Expression in Type-2 Diabetes Mellitus Rat Model Liver: Focus on Exercise

BACKGROUND: Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) has an important role in mitochondria biogenesis which generated cellular metabolism. Carbohydrate metabolism in the liver is crucial to maintain plasma blood glucose. AIM: This research aimed to determine the expression of PGC-1α gene in the liver type-2 diabetes mellitus (T2DM) rat model, after treatment with a focus on exercise. METHODS: We used 25 healthy male Wistar rats as subjects. Rats were modified to T2DM models by feeding a high-fat diet and low-dose streptozotocin injection. We divided the rats into five groups, that is, sedentary group as a control and four others as treatment groups. The exercise was assigned for treatment groups by a run on the treadmill as moderate intensity continuous (MIC), highintensity continuous (HIC), slow interval (SI), and fast interval (FI). The treatment groups were exercise throughout 8 weeks with a frequency of 3 times a week. RESULTS: The results showed that expression of PGC-1α gene was lower in all treatment groups compared to controls (p &lt; 0.05). Expression in HIC was higher than MIC (p &lt; 0.05), so was the expression in FI more than SI (p &lt; 0.05). CONCLUSIONS: Exercise affected PGC-1α gene expression in the liver of the T2DM rat model. The expression of PGC-1α was linear with exercise intensity.

Effect of Agmatine on Non-Alcoholic Fatty Liver Disease Induced by Type 2 Diabetes in Rats

Aim: To determine the potential hepatoprotective effect of Agmatine (AGM) on NAFLD-induced by Type 2 diabetes mellitus (T2DM) in rats.&#x0D; Study design: Forty male Wistar rats weighing from (200 -250 g) were distributed at random into five groups (8 rats per group): group 1 as control; group 2 as untreated-T2DM; groups 3 &amp; 4 as T2DM cotreated with AGM (40 &amp; 80 mg/kg/d), while group 5 T2DM cotreated with Silymarin (100 mg/kg/d).&#x0D; Place and duration of study: Department of Pharmacology, Faculty of Medicine, king Abdul-Aziz University; between October 2020 and January 2021.&#x0D; Methodology: A rat model of T2DM with NAFLD complication was established by feeding rats with 10% fructose in drinking water and intraperitoneally injecting them with a single low dose of streptozotocin (STZ) (45mg/kg). The fasting blood glucose was detected, serum levels of hepatic biomarkers were all assessed. Moreover, histopathological examination was performed by hematoxylin and eosin (H&amp;E) staining.&#x0D; Results: STZ induced T2DM in rats causes a significant (p&lt;0.05, n=8) rise in serum levels of FBG, ALT, AST, TB, TC, TG, and LDL in comparison with the corresponding control group. Co-treatment with AGM (40 &amp; 80 mg/kg) and silymarin significantly alleviated hyperglycemia and amended hepatic biomarkers that was reflected on improved histopathological changes.&#x0D; Conclusion: The current data suggest that oral AGM co-treatment could have a hepatoprotective effect against T2DM associated with NAFLD in rats. Further investigations are recommended to elucidate molecular mechanisms accountable for the useful effects of AGM on hepatocytes.

Cardioprotective effect of icariin against myocardial fibrosis and its molecular mechanism in diabetic cardiomyopathy based on network pharmacology: Role of ICA in DCM

BackgroundDiabetic cardiomyopathy (DCM) is one of the most severe symptoms of diabetes. It continues to be a major clinical problem, but our knowledge of its molecular mechanisms and effective treatments are limited. Traditional Chinese medicine has been shown to be a pool of novel drugs for diabetes. PurposeHerein, we aim to define the molecular mechanism of icariin (ICA), an extract from a traditional Chinese medicine herb, in protecting cardiac structures and restoring cardiac functions of in a rat model of type 2 diabetes mellitus (T2DM). Study design and methodsCandidate genes related to T2DM were identified through bioinformatics screening and their interactions were constructed by molecule docking technique, followed by pathway enrichment analyses of their cellular functions. A T2DM rat model was then established to evaluate the effects of ICA on cardiac structures, myocardial fibrosis, and cellular Ca2+ inflow, as reflected by HE and Masson staining, qRT-PCR and Western blot determination of related genes, and measurement of the L-type Ca2+ current. ResultsFour potential target genes (Jun, p65, NOS3, and PDE5A) were identified. ICA ameliorated the structural damage and myocardial fibrosis in T2DM rats. Intracellular Ca2+ hyperactivities and dysfunction in myocardium of T2DM rats were also repressed by ICA treatment. Furthermore, ICA-induced inhibition of Jun and p65 ameliorated the irregular collagen metabolism and myocardial fibrosis. NOS3, PDE5A and the related sGC-cGMP-PKG signaling pathway mediated the ICA-induced improvement of intracellular Ca2+ inflow. ConclusionIn conclusion, these results demonstrate the regulatory roles of potential target genes in DCM and suggest ICA as an effective treatment of DCM by targeting these genes specifically.

Silencing circANKRD36 inhibits streptozotocin-induced insulin resistance and inflammation in diabetic rats by targeting miR-145 via XBP1.

Diabetes mellitus (DM) is defined as a group of metabolic diseases characterized by hyperglycemia, which results from a deficiency in insulin secretion and/or insulin action. In diabetic patients, type 2 diabetes mellitus (T2DM) is in the majority. We explored the effects of circANKRD36 on streptozotocin (STZ)-induced insulin resistance and inflammation in diabetic rats with the aim of uncovering the underlying mechanism. STZ was used to induce the in vivo T2DM rat model. After circANKRD36 interference, blood glucose, insulin and adiponectin were respectively detected. Hematoxylin and eosin (H&E), enzyme-linked immunosorbent assay (ELISA) and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay (TUNEL) were conducted to examine inflammation and apoptosis in T2DM rats, and western blot was used for detecting apoptosis-related proteins. The binding relationships among circANKRD36, miR-145 and XBP1 were examined by luciferase reporter assay. Results showed that circANKRD36 was expressed at a high level in T2DM rats, while silencing circANKRD36 led to decreased blood glucose and insulin, accompanied by increased adiponectin level, and ameliorating insulin resistance. Silencing circANKRD36 alleviated the inflammation and suppressed cell apoptosis in the pancreatic tissues of T2DM rats, which was abated by miR-145 inhibitor. The binding of miR-145 to XBP1 was then confirmed. Additionally, miR-145 inhibitor increased the level of XBP1 in T2DM rats, which was decreased in the presence of circANKRD36 silencing. This study is the first to prove that silencing circANKRD36 inhibits STZ-induced insulin resistance and inflammation in diabetic rats by targeting miR- 145 via XBP1. The results warrant the importance of circRNAs as drug target and thereby pave way for the development of newer therapeutic measures for T2DM.

Three-dimensional-arterial spin labeling perfusion correlation with diabetes-associated cognitive dysfunction and vascular endothelial growth factor in type 2 diabetes mellitus rat.

BACKGROUNDType 2 diabetes mellitus (T2DM) has been strongly associated with an increased risk of developing cognitive dysfunction and dementia. The mechanisms of diabetes-associated cognitive dysfunction (DACD) have not been fully elucidated to date. Some studies proved lower cerebral blood flow (CBF) in the hippocampus was associated with poor executive function and memory in T2DM. Increasing evidence showed that diabetes leads to abnormal vascular endothelial growth factor (VEGF) expression and CBF changes in humans and animal models. In this study, we hypothesized that DACD was correlated with CBF alteration as measured by three-dimensional (3D) arterial spin labeling (3D-ASL) and VEGF expression in the hippocampus.AIMTo assess the correlation between CBF (measured by 3D-ASL and VEGF expression) and DACD in a rat model of T2DM.METHODSForty Sprague-Dawley male rats were divided into control and T2DM groups. The T2DM group was established by feeding rats a high-fat diet and glucose to induce impaired glucose tolerance and then injecting them with streptozotocin to induce T2DM. Cognitive function was assessed using the Morris water maze experiment. The CBF changes were measured by 3D-ASL magnetic resonance imaging. VEGF expression was determined using immunofluorescence. RESULTSThe escape latency time significantly reduced 15 wk after streptozotocin injection in the T2DM group. The total distance traveled was longer in the T2DM group; also, the platform was crossed fewer times. The percentage of distance in the target zone significantly decreased. CBF decreased in the bilateral hippocampus in the T2DM group. No difference was found between the right CBF value and the left CBF value in the T2DM group. The VEGF expression level in the hippocampus was lower in the T2DM group and correlated with the CBF value. The escape latency negatively correlated with the CBF value. The number of rats crossing the platform positively correlated with the CBF value. CONCLUSIONLow CBF in the hippocampus and decreased VEGF expression might be crucial in DACD. CBF measured by 3D-ASL might serve as a noninvasive imaging biomarker for cognitive impairment associated with T2DM.

Role of TLR4/MyD88/NF-κB signaling in heart and liver-related complications in a rat model of type 2 diabetes mellitus.

AimsTo analyze expression of members of the Toll-like receptor (TLR)4/myeloid differentiation primary response 88 (MyD88)/nuclear factor (NF)-κB signaling pathway in the heart and liver in a rat model of type 2 diabetes mellitus (T2DM). Our overall goal was to understand the underlying pathophysiological mechanisms.MethodsWe measured fasting blood glucose (FBG) and insulin (FINS) in a rat model of T2DM. Expression of members of the TLR4/MyD88/NF-κB signaling pathway as well as downstream cytokines was investigated. Levels of mRNA and protein were assessed using quantitative real-time polymerase chain reaction and western blotting, respectively. Protein content of tissue homogenates was assessed using enzyme-linked immunosorbent assays.ResultsDiabetic rats had lower body weights, higher FBG, higher FINS, and higher intraperitoneal glucose tolerance than normal rats. In addition, biochemical indicators related to heart and liver function were elevated in diabetic rats compared with normal rats. TLR4 and MyD88 were involved in the occurrence of T2DM as well as T2DM-related heart and liver complications. TLR4 caused T2DM-related heart and liver complications through activation of NF-κB.ConclusionsTLR4/MyD88/NF-κB signaling induces production of tumor necrosis factor-α, interleukin-6, and monocyte chemoattractant protein-1, leading to the heart- and liver-related complications of T2DM.

Morus alba leaves ethanol extract protects pancreatic islet cells against dysfunction and death by inducing autophagy in type 2 diabetes

Protection of pancreatic islet cells against dysfunction or death by regulating autophagy is considered to be an effective method for treatment of type 2 diabetes mellitus (T2DM). Morus alba leaves (mulberry leaves), a popular herbal medicine, have been used for prevention of T2DM since ancient times. This study aimed to clarify whether Morus alba leaves ethanol extract (MLE) could protect islet cells in vivo and in vitro by regulating autophagy in T2DM, and explore the possible mechanism of action. The main chemical constituents in MLE were analyzed by HPLC. The T2DM rat model was induced via high-fat diet combined with peritoneal injection of low-dose streptozotocin, and MLE was administered by oral gavage. Fasting blood glucose (FBG) and plasma insulin were measured, and homeostatic model assessment of β cell function (HOMA-β) and insulin resistance (HOMA-IR) were determined. The histomorphology of pancreas islets was evaluated by haematoxylin and eosin staining. In palmitic acid (PA)-stressed INS-1 rat insulinoma cells, cell viability was assayed by an MTT method. Expression of the autophagy-related proteins LC3 I/II, p62, p-AMPK and p-mTOR in islet tissues and INS-1 cells was evaluated by western blotting or immunohistochemistry analysis. The four main chemical constituents in MLE were identified as chlorogenic acid, rutin, isoquercitrin and quercitrin. MLE ameliorated hyperglycemia, insulin resistance and dyslipidemia of T2DM rats with prominent therapeutic effect. Further study indicated that MLE observably improved islet function, alleviated islet injury of T2DM rats, and inhibited PA-induced INS-1 cell death. On the other hand, MLE significantly induced autophagy in islet cells both in vivo and in vitro, and autophagy inhibitors abolished its therapeutic effect on T2DM rats and protective effect on islet cells. Apart from this, MLE markedly activated the AMPK/mTOR pathway in INS-1 cells, and the AMPK inhibitor prevented the autophagy induction ability of MLE. Together, MLE could protect islet cells against dysfunction and death by inducing AMPK/mTOR-mediated autophagy in T2DM, and these findings provide a new perspective for understanding the treatment mechanism of Morus alba leaves against T2DM.

Amelioration of hyperglycaemia and hyperlipidaemia by adjusting the interplay between gut microbiota and bile acid metabolism: Radix Scutellariae as a case

BackgroundOur previous clinical research showed that the interaction between gut microbiota and bile acids (BAs) in patients with type 2 diabetes mellitus (T2DM) changed significantly. We hypothesized that T2DM could be improved by adjusting this interaction mediated by farnesoid X receptor (FXR). T2DM belongs to the category of “xiaoke” in traditional Chinese medicine. Radix scutellariae has the effects of clearing away heat and eliminating dampness, curing jaundice and quenching thirst and is widely used alone or in combination with other medicines for the treatment of T2DM in China and throughout Asia. Additionally, the interaction between Radix scutellariae and gut microbiota may influence its efficacy in the treatment of T2DM. PurposeThis study chose Radix scutellariae to validate that T2DM could improve by adjusting the interaction between gut microbiota and bile acid metabolism. Study design and methodsRadix scutellariae water extract (WESB) was administered to a T2DM rat model established by a high-fat diet combined with streptozotocin. The body weight and blood glucose and insulin levels were measured. The levels of serum lipids, creatinine, uric acid, albumin and total bile acid were also detected. Changes in the pathology and histology of the pancreas, liver and kidney were observed by haematoxylin-eosin staining. The 16S rRNAs of gut microbiota were sequenced, and the faecal and serum BAs were determined by liquid chromatography tandem mass spectrometry. The expression levels of BA metabolism-associated proteins in the liver and intestine were evaluated by immunoblot analysis. ResultsThe results showed that WESB improved hyperglycaemia, hyperlipaemia, and liver and kidney damage in T2DM rats. In addition, the abundances of key gut microbiota and the concentrations of certain secondary BAs in faeces and serum were restored. Moreover, there was a significant correlation between the restored gut microbiota and BAs, which might be related to the activation of liver cholesterol 7α-hydroxylase (CYP7A1) and the inhibition of FXR expression in the intestine rather than the liver. ConclusionsThis study provided new ideas for the prevention or treatment of clinical diabetes and its complications by adjusting the interaction between gut microbiota and bile acid metabolism.