T2DM Rats Research Articles

Candesartan protects against unilateral peripheral limb ischemia in type-2 diabetic rats: Possible contribution of PI3K-Akt-eNOS-VEGF angiogenic signaling pathway

Type-2 diabetes (T2DM) is known to be highly associated with increased risk for vascular complications including peripheral arterial diseases (PAD). Critical limb ischemia (CLI) is the most advanced stage of PAD. Current therapeutic options for diabetic patients experiencing vascular complications are limited to surgical revascularization with no effective pharmacotherapy available for clinical settings. This study is dedicated to evaluate the angiogenic potential of candesartan an angiotensin-II receptor blocker in an experimental model of vascular complications associating T2DM. T2DM was induced in rats through feeding with high fat diet for 6 weeks, followed by injection with streptozotocin (STZ, 30 mg/kg; i.p). After establishment of T2DM, unilateral CLI was induced through the ligation and excision of superficial femoral artery. Candesartan treatment (10 or 30 mg/kg; orally) was initiated one day post CLI and thereafter once daily for up to 14 days. T2DM rats that underwent CLI demonstrated impaired angiogenic signaling, increased inflammation and apoptosis in gastrocnemius muscle (GC). Candesartan reversed ischemic insult in T2DM rats subjected to unilateral CLI and induced reparative angiogenesis that was evident by increase in p-PI3K/PI3K, p-Akt/Akt, p-eNOS/eNOS, p-VEGFR2/VEGFR2 ratios, and VEGF levels. Candesartan treatment also increased levels of HO-1; while decreased caspase-3 apoptotic marker and levels of inflammatory markers; NF-κB and TNF-α, all of which were accompanied by preserved histological manifestations of GC muscles. Candesartan was able to combat limb ischemia under diabetic conditions which could pave the way for its therapeutic utility for diabetic patients experiencing vascular complications in clinical setting.

Metabolic profiling integrated with pharmacokinetics to reveal the material basis of Xiaokeyinshui extract combination in the treatment of type 2 diabetes in rats

Xiaokeyinshui extract combination (XEC), originating from a traditional Chinese formula Xiaokeyinshui (XKYS) recorded in ancient Bencao, has been reported to exert significant hypoglycemic effects. However, the chemical profiles, metabolic transformation and pharmacokinetic behavior of XEC in vivo were unclear. The research was to investigate the chemical constituents, metabolic profiles and pharmacokinetic behavior of XEC. A UPLC-QE-Orbitrap-HRMS qualification method was developed to identify the chemical constituents in XEC and xenobiotics of XEC in plasma, urine, feces and bile of rats after oral administration. A LC-MS quantification method was established and applied for the pharmacokinetic studies of major active compounds of XEC in normal and T2DM rats and Coptidis Rhizoma extracts (CRE) in T2DM rats. Fifty eight compounds in XEC and a total of 152 xenobiotics were identified in T2DM rats, including 28 prototypes and 124 metabolites. The metabolic pathways were demethylation, demethyleneization, reduction, hydroxylation, hydrolysis and subsequent binding reactions, including glucuronidation, sulfation and methylation. According to the results of chemical constituents and metabolites, 7 ingredients, including berberine, palmatine, coptisine, epiberberine, berberrubine, magnoflorine and aurantio-obtusin were suggested for markers to comparative pharmacokinetics study in normal rats and T2DM rats. Compared with normal rats, the Tmax of berberine, palmatine, coptisine, epiberberine, berberrubine and magnoflorine was significantly longer. The value of Cmax for palmatine, coptisine, epiberberine and berberrubine was significantly decreased in XEC T2DM group. The value of AUC for alkaloids was higher in diabetic rats. After oral CRE, alkaloids including berberine, palmatine, coptisine, epiberberine, berberrubine and magnoflorine could be detected in vivo. Compared with T2DM rats after oral administration of CRE, the value of Tmax and Cmax for berberine, palmatine, coptisine, epiberberine, berberrubine and magnoflorine exhibited significant differences in XEC T2DM group. This research provided an overview of the chemical profiles and metabolic profiling of XEC and elucidated the effect of diabetic state and compatibility on pharmacokinetic behaviors of active components in XEC. This research also can provide the material basis of XEC for subsequent quality control research.

Ischemia reperfusion myocardium injuries in type 2 diabetic rats: Effects of ketamine and insulin on LC3-II and mTOR expression.

Objectives: Myocardiopathy occurs in ischemia-induced injury caused by dysregulation of autophagy of cardiac tissues. The present report evaluates the protective effect of ketamine and insulin against myocardial injury in type 2 diabetic rats (T2DM).Methods: The effects of ketamine and its combination with insulin on biochemical parameters and inflammatory cytokines in the serum of I/R-induced myocardial injury in T2DM rats were evaluated. The parameters of reactive oxygen species and the expression of autophagosome signaling pathway proteins were also determined. Using transmission electron microscopy, we investigated autophagosomes. Western blots were used to detect autophagy-associated signaling pathways. Myocardial function was determined by echocardiography and histopathological changes in myocardial tissues were also determined in I/R-induced myocardial injury in type 2 diabetic rats.Results: There was a significant reduction in glucose, AST, LDH, and CK-MB levels and cytokines (IL-1β, IL-6, and TNF-α) in serum of the ketamine (p < .05) and ketamine + insulin (p < .01) groups than in the diabetic + I/R. MDA and ROS levels were reduced with a substantial (p < .05) increase in GSH levels through improved cardiac function in the ketamine (p < .05) and ketamine + insulin (p < .01) groups than the diabetic + I/R group. There was an increase in mature autophagosomes in diabetic+I/R+Kt+In compared to diabetic+I/R+Kt alone in infarction and marginal zones. It should be noted that the significant increase (p < .01) in protein levels of the autophagy-associated intracellular signaling pathways AMPK and mTOR, as well as an increase in LC3-II and BECLIN-1, suggests that ketamine combined with insulin-activated autophagy-associated intracellular signaling AMPK and mTOR.Conclusion: The findings of the study suggest that ketamine combined with insulin administration remarkably protects I/R-induced myocardial injury in rats with T2DM by reducing the dysregulation of autophagy.

Bone marrow-derived mesenchymal stem cell-conditioned medium ameliorates diabetic foot ulcers in rats

ObjectivesThis study aimed to explore the effects of bone marrow-derived Mesenchymal Stem Cell-Conditioned Medium (MSC-CM) treating diabetic foot ulcers in rats. MethodsModels of T2DM rats were induced by a high-fat diet and intraperitoneal injection of STZ in SD rats. Models of Diabetic Foot Ulcers (DFUs) were made by operation on hind limbs in diabetic rats. Rats were divided into four groups (n = 6 for each group), i.e., Normal Control group (NC), Diabetes Control group (DM-C), MSC-CM group and Mesenchymal Stem Cells group (MSCs). MSC-CM group was treated with an injection of conditioned medium derived from preconditioned rats' bone marrow MSCs around ulcers. MSCs group were treated with an injection of rats' bone marrow MSCs. The other two groups were treated with an injection of PBS. After the treatment, wound closure, re-epithelialization (thickness of the stratum granulosums of the skin, by H&E staining), cell proliferation (Ki67, by IHC), angiogenesis (CD31, by IFC), autophagy (LC3B, by IFC and WB; autolysosome, by EM) and pyroptosis (IL-1β, NLRP3, Caspase-1, GSDMD and GSDMD-N, by WB) in ulcers were evaluated. ResultsAfter the treatment wound area rate, IL-1β by ELISA, and IL-1β, Caspase-1, GSDMD and GSDMD-N by WB of MSC-CM group were less than those of DM group. The thickness of the stratum granulosums of the skin, proliferation index of Ki67, mean optic density of CD31 and LC3B by IFC, and LC3B by WB of MSC-CM group were more than those of DM group. The present analysis demonstrated that the injection of MSC-CM into rats with DFUs enhanced the wound-healing process by accelerating wound closure, promoting cell proliferation and angiogenesis, enhancing cell autophagy, and reducing cell pyroptosis in ulcers. ConclusionsStudies conducted indicate that MSC-CM administration could be a novel cell-free therapeutic approach to treat DFUs accelerating the wound healing process and avoiding the risk of living cells therapy.

Mechanism of Baihu Renshen decoction on T2DM rats based on mitochondrial autophagy mediated by PINK1/Parkin

Mechanism of Baihu Renshen decoction on T2DM rats based on mitochondrial autophagy mediated by PINK1/Parkin

Antidiabetic and Antihyperlipidemic Activity of β-carotene on Streptozotocin-induced Diabetic Rats

Objective: A vital anti-oxidant, β-carotene has the capacity to reduce reactive oxidative stress, metabolic syndrome such as Type 2 (T2) Diabetes Mellitus (DM) and prevent inflammation, obesity, alzheimer and cardiovascular diseases in human. In this study, we evaluated the efficacy of β-carotene on streptozotocin (STZ)- induced T2DM rats.&#x0D; Methods: Diabetes was induced in Wister rats through the intraperitoneal administration of STZ (50 mg/kg b.w.). Antihyperlipidemic activities of β-carotene were evaluated by oral dose (10 mg/70 kg b.w.) once daily for 21 days. Metformin (12.1 mg/kg b.w.) was used as a positive control.&#x0D; Results: Blood samples of rats were drawn by tail vein puncture and cardiac puncture to determine the fasting blood glucose (FBG) and serum level of total cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL) and high-density lipoprotein (HDL), respectively. The result of individual treatment of β-carotene and metformin significantly (p&lt;0.001) reversed the diabetes induced increase in FBG, LDL, TC and TG, whereas pointedly increased the STZ-induced decrease in HDL, if compared to the diabetic control.&#x0D; Conclusion: The monotherapy of β-carotene had important antidiabetic and antihyperlipidemic effects and provided a scientific rationale for their use in antidiabetic therapy as a potential antioxidant.

Pumpkin Polysaccharide Extracted by Subcritical Water: Physicochemical Characterization and Anti-Diabetic Effects in T2DM Rats.

This study aims to optimize the extraction of pumpkin polysaccharide by subcritical water, investigates the physicochemical properties and biological activities of pumpkin polysaccharide. Subcritical water is used to extract pumpkin polysaccharide. The structure and composition of pumpkin polysaccharide are analyzed by infrared spectroscopy, gel filtration chromatography, and high-performance liquid chromatography. The hypoglycemic and hypolipidemic potential of pumpkin polysaccharide aere determined by the physicochemical indexes, pathological, and immunohistochemical analysis in T2DM rats induced by STZ + high-fat diet. The optimal conditions for subcritical water are 1:15, 150°C, and 10min. Pumpkin polysaccharide has α-configurations and are mainly composed of seven different monosaccharides, and it exhibits good free-radical scavenging ability and inhibition of α-amylase, α-glucosidase, and pancreatic lipase activities. Pumpkin polysaccharide treatment in T2DM rats significantly decreases the concentrations of blood glucose, insulin, TC, TG, LDL-C, and MDA; increases the levels of HDL-C; and enhances the antioxidant enzymes activities (SOD and CAT). Histopathology and immunohistochemical analyses reveal that pumpkin polysaccharide has protective effects on kidney and pancreatic organs in T2DM rats. Pumpkin polysaccharide extracted by SWE shows great potential as functional food ingredients and candidates for T2DM treatment.

Protective effects of black onion polysaccharide on liver and kidney injury in T2DM rats through the synergistic impact of hypolipidemic and antioxidant abilities

In this study, the synergistic effects of black onion on the hypolipidemic and antioxidant activities in T2DM rats induced by a high-fat-diet and alloxan were investigated. The results showed that the fasting blood glucose of diabetic rats was significantly decreased after treatment with black onion polysaccharide (p < 0.01). Blood lipid analysis indicated that black onion polysaccharide could significantly improve the abnormal metabolism of blood lipids caused by diabetes. In addition, the MDA and ROS of the diabetic rats treated with black onion polysaccharide were significantly reduced; moreover, SOD was increased, indicating the excellent antioxidant activity of black onion polysaccharide. A histological examination clearly showed that black onion polysaccharide could improve the histological morphology of the liver and kidney. Furthermore, the indices of liver and kidney function were restored. These results indicate that black onion polysaccharide can reduce blood glucose and simultaneously show synergistic effects of hypoglycemic and antioxidant activities in diabetic rats. Therefore, black onion polysaccharide may alleviate liver and kidney function injury by improving the “two-hit” mechanism and can thus be used as a potential functional food to prevent diabetes and its complications.

Mesenchymal Stem Cell Transplantation Increases Antioxidant Protein Expression and Ameliorates GP91/ROS/Inflammasome Signals in Diabetic Cardiomyopathy.

Cardiomyopathy is one of the complications associated with diabetes. Due to its high prevalence, diabetic cardiomyopathy has become an urgent issue for diabetic patients. Various pathological signals are related to diabetic cardiomyopathy progress, including inflammasome. Mesenchymal stem cell transplantation is full of potential for the treatment of diabetic cardiomyopathy because of stem cell cardiac regenerative capability. This study investigates whether mesenchymal stem cell transplantation shows therapeutic effects on diabetic cardiomyopathy through inflammasome signaling regulation. Wistar male rats were divided into three groups including Sham, T1DM (rats with type 1 diabetes) and T1DM + WJSC (T1DM rats receiving 1 × 106 stem cells per rat). Compared to the Sham, experimental results indicated that several pathological conditions can be observed in heart tissues with T1DM, including structural change, fibrosis, oxidative stress elevation and inflammasome related protein expression. All of these pathological conditions were significantly improved in T1DM rats receiving mesenchymal stem cell transplantation (T1DM + WJSC). Furthermore, the experimental findings suggest that mesenchymal stem cell transplantation exerted antioxidant protein expression in diabetic heart tissues, resulting in a decrease in oxidative stress and inflammasome signaling blockage. These findings imply that mesenchymal stem cell transplantation shows therapeutic effects on diabetic cardiomyopathy through inflammasome regulation induced by oxidative stress.

Resveratrol improves diabetic cardiomyopathy by preventing asymmetric dimethylarginine-caused peroxisome proliferator-activated receptor-γ coactivator-1α acetylation

ObjectivesCardiac protection of resveratrol is related to the improvement of mitochondrial function through sirtuin1 (SIRT1) activation and peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) deacetylation. Asymmetric dimethylarginine (ADMA) as an endogenous inhibitor of nitric oxide synthases is associated with diabetic cardiovascular complications and has a cross-talk with lysine acetylation. This study was to determine whether resveratrol reverses ADMA's pathogenic role in diabetic cardiomyopathy and elucidate the underlying mechanisms in type 2 diabetic (T2DM) rats and cardiomyocytes. MethodsT2DM Rats were induced by high-fat diet plus small-dose streptozotocin injection (35 mg/kg). Resveratrol was given by gavage (50 mg/kg/d) to some rats for 16w. Cardiac function was measured by echocardiography, and PGC-1α acetylation was detected by immunoprecipitation. Mitochondrial DNA and ATP contents were analyzed to evaluate mitochondrial biogenesis and function. ResultsEndogenous ADMA accumulation and its signal disorders were associated with cardiac and mitochondrial dysfunctions in accompany with increased PGC-1α acetylation and decreased PGC-1α expression in the myocardium of T2DM rats compared with control rats. Resveratrol treatment attenuated ADMA accumulation, cardiac and mitochondrial dysfunctions in parallel with reversing altered PGC-1α expression and acetylation in the myocardium of T2DM rats. Exogenous ADMA not only reproduced mitochondrial dysfunction and cardiac hypertrophy but also reduced PGC-1α expression and enhanced PGC-1α acetylation in accompany of down-regulating SIRT1 and up-regulating acetyltransferase expression, all of which could be prevented by resveratrol pretreatment in cardiomyocytes. ConclusionsThese results indicate that ADMA promotes PGC-1α acetylation as a potential therapeutic target for resveratrol of management diabetic cardiomyopathy in T2DM rats.

Fufang Fanshiliu Decoction Revealed the Antidiabetic Effect through Modulating Inflammatory Response and Gut Microbiota Composition.

Background Diabetes mellitus brings serious threats and financial burdens to human beings worldwide. Fufang Fanshiliu decoction (FFSLD), a traditional Chinese medicine formula showing great antidiabetic effects, has been used in clinics for many years. Objective This study aims to explore the underlying therapeutic mechanisms of FFSLD in Type II diabetes mellitus (T2DM). Methods Sprague–Dawley rats induced by high-fat diet feeding combined with streptozotocin injection were used to establish the T2DM model. All rats were randomly divided into 6 groups: control, model, metformin, high dosage, middle dosage, and low dosage of FFSLD. After 4 weeks of treatment, serum, intestinal mucosa, and fecal samples were collected for further analysis. ELISA was used to detect the diabetic-related serum indicators and proinflammation cytokines. Gene or protein expressions of mitogen-activated protein kinase (MAPK), interleukin 1 beta (IL-1β), transforming growth factor-beta (TGF-β), and tumor necrosis factor-alpha (TNF-α) in intestinal mucosa were analyzed by quantitative real-time polymerase chain reaction (RT-PCR) or western blot. 16s rRNA gene sequencing was used to detect the changes of gut microbiome in these groups. Intestinal gut microbiota (GM) composition was further analyzed according to the sequencing libraries. Results FFSLD effectively recovered the diabetic-related biochemical indexes by reducing fasting blood glucose (FBG), total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), insulin, and increasing high-density lipoprotein cholesterol (HDL-C). Furthermore, FFSLD significantly ameliorated the abnormal levels of proinflammation cytokines including IL-1β, IL-6, TNF-α, and TGF-β. In addition, the GM compositions of rats in control, model, and FFSLD treated groups were different. FFSLD significantly increased the relative abundance of Lactobacillus, Akkermansia, and Proteus, and reduced the relative abundance of Alistipes, Desulfovibrio, and Helicobacter. Moreover, these changed bacteria were closely related to the diabetic-related serum indicators and proinflammatory cytokines. Conclusion These results suggest that FFSLD alleviates diabetic symptoms in T2DM rats through regulating GM composition and inhibiting inflammatory response, which clarify the therapeutic mechanism of FFSLD on T2DM and provide a theoretical basis for its further clinical application.

Therapeutic effect and mechanism of combination therapy with ursolic acid and insulin on diabetic nephropathy in a type I diabetic rat model.

This work aims to investigate the therapeutic effect of ursolic acid (UA) plus insulin (In) on diabetic nephropathy (DN) in streptozotocin (STZ)-induced T1DM rats. The experimental groups and operational details are as follows: A total of thirty-two SD rats were divided into four groups: the DN model group (DN, n = 8), DN + In treatment group (DN + In, n = 8), DN + In + UA administration group (DN + In + UA, n = 8), and negative control group (control, n = 8). After 8 weeks, changes in renal function indices and pathological damage were assessed. Additionally, oxidative stress-, apoptosis-, and fibrosis-related proteins in kidney tissue were measured. Compared with the control group, the vehicle group showed higher levels of creatine, blood urea nitrogen, urinary protein, apoptosis, and lipid peroxidation; lower superoxide dismutase levels; more severe levels of pathological kidney damage and renal fibrosis; and a deepened degree of EMT and EndMT. Better outcomes were achieved with the combined treatment than with insulin-only treatment. The improvement of TGF-β1, phosphorylated p38 MAPK, FGFR1, SIRT3 and DPP-4 expression levels in renal tissues after combination therapy was greater than that after insulin-only treatment. This study shows that the combination of insulin and UA significantly improved the pathological changes in the renal tissue of T1DM rats, and the underlying mechanism may be related to improving apoptosis and oxidative stress by regulating p38 MAPK, SIRT3, DPP-4 and FGFR1 levels, thereby blocking TGF-β signaling pathway activation and inhibiting EMT and EndMT processes.

Dietary fiber konjac glucomannan exerts an antidiabetic effect via inhibiting lipid absorption and regulation of PPAR-γ and gut microbiome

Konjac glucomannan’s influence on the regulation of diabetes mellitus, hyperlipidemia, and gut microbial flora was evaluated in this study. In addition, a high-fat diet and streptozotocin were used to induce type 2 diabetes mellitus in rats. At the end of the study, we analyzed various parameters such as body weight, plasma lipid profile, insulin levels by immunohistochemistry, degree of fibrosis in the liver, protein expression of PPAR-γ and p-SREBP-1C and gut microbial changes using 16S rRNA sequencing. The results of our study suggest that KGM supplementation significantly reduced the plasma lipid profile (TC, TG, VLDL, LDL, etc.). In addition, KGM has improved insulin levels, which were visualized using immunohistochemistry. Furthermore, KGM also regulated the protein expression of key regulatory proteins of lipid metabolism PPAR-γ and p-SREBP-1C (Group 3). Similar results were seen in the groups treated with the standard drug rosiglitazone (group 4). Finally, the 16S rRNA sequencing shows that KGM contributes to gut microbiota composition alterations, and it was observed using the Simpson, Shannon, Chao-1, and actual otus indices (group 3). KGM further alters the production of beneficial SCFAs and helps host good health. Furthermore, several metabolic pathways have been activated in T2DM rats. As a result, it becomes apparent that the digestive system's microbiome will play a role in T2DM. KGM has various health advantages but is particularly useful in treating hyperlipidemia and diabetes.

Sexual dimorphism in response to repetitive bouts of acute aerobic exercise in rodents with type 1 diabetes mellitus.

The purpose of this study was to examine sex-specific differences in the blood glucose (BG) response to recurrent aerobic exercise in type 1 diabetes rats. Specifically, we examined the role of peak estrogen (E2) concentrations during proestrus on BG response to prolonged repetitive aerobic exercise. To do so, nineteen Sprague-Dawley rats were assigned to four exercised groups: control female (CXF; n = 5), control male (CXM; n = 5), diabetic female (DXF, n = 5) and diabetic male (DXM, n = 4). Diabetes was induced in DX groups via subcutaneous multiple injections of low dose streptozotocin (20mg/day for 7 days). After four days of exercise, muscle and liver glycogen content, liver gluconeogenic enzyme content, muscle Beta oxidation activity and BG responses to exercise were compared. The final bout of exercise took place during proestrus when E2 concentrations were at their highest in the female rats. During days 1–3 DXM had significantly lower BG concentrations during exercise than DXF. While both T1DM and non-T1DM females demonstrated higher hepatic G6Pase expression and muscle beta oxidation activity levels on day 4 exercise, no differences in BG response between the male and female T1DM rats were evident. Further, no differences in liver and muscle glycogen content following day 4 of exercise were seen between the sexes. These results would suggest that heightened E2 levels during proestrus may not be an important factor governing glucose counter regulatory response to exercise in female T1DM rats. Rather, the pre-exercise blood glucose levels are likely to be a large determinant of the blood glucose response to exercise in both male and female rats.

Type 2 Diabetes Induces a Pro-Oxidative Environment in Rat Epididymis by Disrupting SIRT1/PGC-1α/SIRT3 Pathway.

Diabetes mellitus type 2 (T2DM) has been associated with alterations in the male reproductive tract, especially in the epididymis. Although it is known that T2DM alters epididymal physiology, disturbing mitochondrial function and favoring oxidative stress, the mechanisms remain unknown. Sirtuin 1 (SIRT1), peroxisome proliferators-activated receptor γ coactivator 1α (PGC-1α), and sirtuin 3 (SIRT3) are key regulators of mitochondrial function and inducers of antioxidant defenses. In this study, we hypothesized that the epididymal SIRT1/PGC-1α/SIRT3 axis mediates T2DM-induced epididymis dysfunction by controlling the oxidative profile. Using 7 Goto-Kakizaki (GK) rats (a non-obese model that spontaneously develops T2DM early in life), and 7 age-matched Wistar control rats, we evaluated the protein levels of SIRT1, PGC-1α, and SIRT3, as well as the expression of mitochondrial respiratory complexes. The activities of epididymal glutathione peroxidase (GPx), glutathione reductase (GR), superoxide dismutase (SOD), and catalase (CAT) were determined, as well as the epididymal antioxidant capacity. We also evaluated protein nitration, carbonylation, and lipid peroxidation in the epididymis. The T2DM rats presented with hyperglycemia and glucose intolerance. Epididymal levels of SIRT1, PGC-1α, and SIRT3 were decreased, as well as the expression of the mitochondrial complexes II, III, and V, in the T2DM rats. We found a significant decrease in the activities of SOD, CAT, and GPx, consistent with the lower antioxidant capacity and higher protein nitration and lipid peroxidation detected in the epididymis of the T2DM rats. In sum, T2DM disrupted the epididymal SIRT1/PGC-1α/SIRT3 pathway, which is associated with a compromised mitochondrial function. This resulted in a decline of the antioxidant defenses and an increased oxidative damage in that tissue, which may be responsible for the impaired male reproductive function observed in diabetic men.

Therapeutic Effects and Mechanism of Liraglutide in Rats with Type 2 Diabetes and Metabolic-associated Fatty Liver Disease.

SREBP-1c/Insig/SCAP acts as a lipid de novo synthesis pathway, and its factors are highly expressed in the endoplasmic reticulum. At present, this pathway has become a research hotspot in the development of metabolic-associated fatty liver disease. However, there are few studies on how various factors in this pathway change after endoplasmic reticulum stress; in particular, the role of the insulin-inducing gene-1 (Insig-1) has not been elucidated in detail. The aim of the study was to investigate whether liraglutide has a therapeutic effect on rats with T2DM and MAFLD, and to further study its possible mechanism. Rats in the control group and modeling group were fed with normal diet and high-sugar and high-fat diet, respectively. After one month, the mice in the modeling group were injected with 35mg/kg STZ intraperitoneally to establish the model of type 2 diabetes mellitus. T2DM and MAFLD rats were randomly divided into three groups: model group, low-dose liraglutide group, and high-dose liraglutide group. Fasting blood glucose, fasting insulin, blood lipid profile, alanine aminotransferase, and aspartate aminotransferase were measured at the end of 8th week. Paraffin sections were obtained from the same part of the liver of rats in each group and observed by electron microscope after HE staining. Western blot was used to detect the expression of endoplasmic reticulum stress index (GRP78) and negative feedback index of lipid synthesis (Insig-1) in each group. Liver tissue from the drug intervention groups demonstrated a decrease in lipid droplet vacuoles, and the hepatocytes were arranged neatly again. While the expression of GRP78 rose, that of Insig-1 declined. There were differences observed with different doses of liraglutide; the higher the dose was, the more obvious the effect. No such changes were observed in T2DM and MAFLD rats after injection of saline. In this study, we show that liraglutide may have a therapeutic effect on rats with T2DM and MAFLD by reducing endoplasmic reticulum stress in the liver and increasing the expression of Insig-1.

Ferulic acid and vinpocetine intake improves memory function by enhancing insulin sensitivity and reducing neuroinflammation and oxidative stress in type 2 diabetic animals with induced Alzheimer's disease

• Vinpocetine and ferulic acid intakes suppressed the memory deficits by hippocampal amyloid-β infusion in diabetic rats. • Vinpocetine and ferulic acid intake lowered systemic insulin resistance than the rats without amyloid-β infusion. • Vinpocetine and ferulic acid intake potentiated hippocampal insulin signaling and reduced neuroinflammation. • Ferulic acid intake additionally decreased oxidative stress in the hippocampus. • Ferulic acid intake improved memory deficit as much as the rats without amyloid-β infusion. We aimed to examine the hypothesis that dietary ferulic acid and vinpocetine intake improve the memory deficits caused by hippocampal amyloid-β accumulation in type 2 diabetic(T2DM) rats with induced Alzheimer’s disease(AD). Their mechanisms were also tested. Partial pancreatectomized animals with hippocampal amyloid-β(25–35) infusion representing Asian T2DM developed AD (AD rats; memory deficit). After the eight-week intervention, memory impairment was impeded in the AD-FRA fed ferulic acid(50 mg/kg BW) and AD-VPC vinpocetine(50 mg/kg BW; AD-VPC) through the inhibition of amyloid-β deposition and neuroinflammation compared to the AD-CON. The AD-FRA showed less amyloid-β deposition than the AD-VPC group. The AD-FRA and AD-VPC groups showed an inhibited attenuation of the hippocampal phosphorylated Akt → glycogen-synthase kinase(GSK)-3β → forkhead box protein O1(FOXO1) pathway, and AD-FRA showed similar protection as CON. No adverse effects in AD-FRA and AD-VPC were detected. In conclusion, vinpocetine and ferulic acid supplementation suppressed the memory deficits in T2DM rats with AD, and ferulic acid showed better improvement than vinpocetine, similar to no AD-induced rats.

Evaluation of Hypoglycemic and Hypolipidemic Activities of Methanolic Leaf Extract of Garcinia gummi-gutta Linn by HFD with Low Dose STZ Induced Type II Diabetes Mellitus on Rats

Objective: The present study aimed to evaluate the hypoglycemic and hypolipidemic activities of methanolic leaf extract of Garcinia gummi-gutta Linn. by HFD with low dose STZ induced T2DM on rats.&#x0D; Materials and Methods: The animals were divided into five groups of six animals, and HFD was induced for 8 weeks. After 4th week of HFD treatment, type-II diabetes was induced by a single dose of 35mg/kg (i.p) STZ, hyperglycemia was confirmed by the elevated levels of blood glucose determined at 72h and the animals with blood glucose concentration (&lt; 250mg/dl) were used for the study. The In vitro anti-diabetic activity was done by the DNS method.&#x0D; Results: The In vitro anti-diabetic activity by α-amylase inhibition activity by DNS method was very mild as compared to Acarbose and the IC50 value of Acarbose was very low (170.84µg/ml) than MEGG (1989.59µg/ml). However, potent In vivo anti-diabetic activity (P&lt;0.001) was observed after induction HFD with low dose STZ induced T2DM rats at the end of the 8th week, blood sugar level for MEGG high dose (173.40 ± 14.9mg/dl) was found to be almost same as that of standard drug Glibenclamide (164.60 ± 3.21mg/dl) as compared to control (287.90 ± 1.52). The lipid profile of the study showed a marked increase in TC, LDL, TG, and reduction in HDL in HFD with low dose STZ diabetic rats, whereas in MEGG and standard drugs treated by Glibenclamide were found to be substantially decreased and a fair amount of improvement in HDL level (P&lt;0.001). Histologically, focal necrosis was observed in the diabetic rat pancreas whereas on standard and test mild and no evidence of necrosis were observed respectively, similar positive results were found in liver and adipocyte histology for standard and test groups against the HFD with STZ-induced group&#x0D; Conclusion: Therefore MEGG possesses potent In vivo anti-diabetic effect as well as hypolipidemic effect and therefore MEGG might be a potent phytochemical alternative to prevent and treat T2DM and atherosclerosis and also to reduce its associated complications.

Combined resveratrol and vitamin D treatment ameliorate inflammation-related liver fibrosis, ER stress, and apoptosis in a high-fructose diet/streptozotocin-induced T2DM model.

A high fructose diet is a major cause of diabetes and various metabolic disorders, including fatty liver. In this study, we investigated the effects of resveratrol and vitamin D (VitD) treatments on endoplasmic reticulum (ER) stress, oxidative stress, inflammation, apoptosis, and liver regeneration in a rat model of type 2 diabetes mellitus, namely, T2DM Sprague-Dawley rats. This T2DM rat model was created through a combination treatment of a 10% fructose diet and 40mg/kg streptozotocin (STZ). Resveratrol (1mg/kg/day) and VitD (170/IU/week) were administered alone and in combination to both the diabetic and control groups. Immunohistochemical staining was performed to evaluate PCNA, NF-κB, TNF-α, IL-6, IL-1β, GRP78, and active caspase-3 in liver tissue. The TUNEL method and Sirius red staining were used to determine apoptosis and fibrosis, respectively. G6PD, 6-PGD, GR, and GST activities were measured to determine oxidative stress status. We found that the expressions of cytokines (TNF-α, IL-6, and IL-1β) correlated with NF-κB activation and were significantly increased in the T2DM rats. Increased GRP78 expression, indicating ER stress, increased in apoptotic cells, enhanced caspase-3 activation, and collagen accumulation surrounding the central vein were observed in the T2DM group compared with the other groups. The combination VitD + resveratrol treatment improved antioxidant defense via increasing G6PD, 6-PGD, GR, and GST activities compared to the diabetic groups. We concluded that the combined administration of resveratrol with VitD ameliorates the adverse effects of T2DM by regulating blood glucose levels, increasing antioxidant defense mechanisms, controlling ER stress, enhancing tissue regeneration, improving inflammation, and reducing apoptosis in liver cells. In conclusion, this study indicates that the combination treatment of resveratrol + VitD can be a beneficial option for preventing liver damage in fructose-induced T2DM.

The Association of lncRNA and mRNA Changes in Adipose Tissue with Improved Insulin Resistance in Type 2 Obese Diabetes Mellitus Rats after Roux-en-Y Gastric Bypass.

Objective Roux-en-Y gastric bypass (RYGB) has shown good effects in improving obesity and type II diabetes mellitus (T2DM), but the underlying mechanisms remain unclear. This study explored the changes of related lncRNAs, mRNAs, and signaling pathways in white adipose tissue of T2DM rats after RYGB based on RNA-Seq sequencing, with the aim to provide a theoretical basis for RYGB treatment. Methods T2DM rat models were established by continuous feeding with a high-fat diet and injection of streptozotocin (STZ), after which they underwent RYGB or sham surgery. After the surgery, their body weight was measured weekly. Their fasting blood glucose (FBG) and fasting serum insulin (FSI) were also measured. A homeostasis model assessment of insulin resistance (HOMA-IR) was calculated at weeks 0, 8, and 12. Besides, white adipose tissue of T2DM rats was collected for RNA-Seq sequencing and validated by qRT-PCR. A series of bioinformatics analyses, such as differential expression genes (DEGs) screening, was performed. GO and KEGG functional enrichment analysis and protein-protein interaction (PPI) network construction were conducted based on the sequencing data. Results RYGB surgery could significantly inhibit the weight growth rate and decrease the FBG, FSI, and HOMA-IR of T2DM rats. Bioinformatics analysis of RNA sequencing (RNA-Seq) results revealed that 87 DE- lncRNAs (49 upregulated and 38 downregulated) and 1,824 DEGs (896 upregulated and 928 downregulated) were present in between the RYGB group and Sham group. GO and KEGG analysis showed that the target genes of DEGs and differentially expressed lncRNAs (DE-lncRNAs) were mainly associated with amino acid metabolism, fatty acid metabolism, channel activity, and other processes. In addition, the PPI network diagram also displayed that genes such as Fasn, Grin3a, and Nog could be key genes playing a role after RYGB. qRT-PCR showed that the expression level of Grin3a in the RYGB group was significantly increased compared with the Sham group, while the expression of Fasn and Nog was significantly decreased, which was consistent with the sequencing results. Conclusion Using RNA-Seq sequencing, this study revealed the changes of related lncRNAs, mRNAs, and signaling pathways in the white adipose tissue of T2DM rats after RYGB and identified Fasn, Grin3a, and Nog as potential key genes to function after RYGB.