Triptolide prolonged allogeneic islet graft survival in chemically induced and spontaneously diabetic mice without impairment of islet function

BACKGROUND: Triptolide (TPT) is a diterpenoid triepoxide extracted from the Chinese herb Tripterygium wilfordii Hook. F. It exhibits potent immunosuppressive and anti-inflammatory properties. This study was undertaken to investigate its effects on prolongation of islet allograft survival in rodents. Additionally, we investigated whether TPT would be toxic to islet function in vivo. METHODS: We transplanted BALB/c islets to either chemically induced diabetic C57BL/6 mice or spontaneously diabetic non-obese diabetic (NOD) mice. TPT was injected within 2 weeks or continuously, until rejection, in the two combinations. Then, we evaluated the toxicity of TPT on islet function by daily injection to naive BALB/c or diabetic BALB/c that was cured by syngeneic islet transplantation under the kidney capsule. Mice injected with cyclosporine A (CsA) or vehicle served as controls. Intraperitoneal glucose tolerance tests (IPGTTs) performed at 4 and 8 weeks in the naive BALB/c group, and at 2, 4, 6, and 8 weeks in the syngeneic transplanted group. RESULTS: The medium survival time of islets allograft from TPT treated C57BL/6 and NOD recipients were 28.5 days (range 24-30 days, n=10) and 33.0 days (range 15-47 days, n=6), respectively, and they were significantly different from those of the vehicle treated controls, which were 14.0 days (range 13-16 days, n=6) and 5.0 days (range 4-10 days, n=6), respectively (all P<0.0001). The IPGTT demonstrated that there was no difference between the TPT treated and vehicle treated groups, either in the normal or syngeneic transplanted islet BALB/c mice. However, CsA injection impaired islet function in both normal and syngeneic transplanted mice as early as 4 weeks. CONCLUSION: TPT prolonged islets allograft survival in a chemically induced diabetic or an autoimmune diabetic murine model without impairment of islet function. (Hepatobiliary Pancreat Dis Int 2010; 9: 312-318)

PDE5 inhibitors promote recovery of peripheral neuropathy in diabetic mice

Diabetes mellitus affects an estimated 422 million people worldwide.Peripheral neuropathy is one of the most common and disabling complications of diabetes.There is currently no effective treatment for diabetic neuropathy,

Transfusion of CXCR4-priming endothelial progenitor cells reduces cerebral ischemic damage and promotes angiogenesis and neurogenesis in db/db diabetic mice

Previous studies suggest that reduction and dysfunction of circulating endothelial progenitor cells(EPCs),and dysregulation in stromal cell derived factor-1/CXC-chemokine receptor 4(SDF-1/ CXCR4) axis in diabetes could be therapeutic targets for diabetic ischemic stroke.This study investigated the efficacy of CXCR4-priming EPCs on cerebral repair following ischemic stroke in db/db diabetic mice.Bone marrow derived EPCs from db/+ control mice were transfected with adenovirus(1×10~7 IU) carrying CXCR4(Ad-CXCR4-EPCs)or null(Ad- null-EPCs).The db/db mice were divided into three groups for EPCs injection(2×10~5 cells/100μl): Ad-CXCR4-EPCs,Ad-null-EPCs or saline(vehicle), via tail vein 2 hrs after middle cerebral artery occlusion (MCAO) surgery.Cerebral blood flow(CBF) was measured with laser Doppler flowmeter.Mice were sacrificed at 2 or 7 days thereafter.Level of circulating EPCs was measured by flow cytometry. Ischemic damage,cerebral microvascular density (MVD),angiogenesis and neurogenesis were determined by histological staining with Fluoro-J,CD31, CD31 +BrdU,NeuN +BrdU,GFAP+BrdU,respectively. Results(table) showed:1) Levels of CXCR4 expression were reduced in the brain and EPCs of db/db mice as measured by real-time RT-PCR and western blot analyses(data not shown);2) The level of circulating EPCs was more in the mice treated with Ad-CXCR4-EPCs;3)EPC transfusion improved CBF,increased MVD,angiogenesis and neurogenesis in peri-infarct area,and decreased ischemic damage.The efficacies were better in Ad-CXCR4 -EPCs group.Data suggest that transfusion of Ad-CXCR4-EPCs could be a therapeutic avenue for ischemia stroke in diabetes.

Study on the effect of Rhizoma Anemarrhenae on glucose and lipid metabolism in diabetic mice

Objective:To investigate the effect of Rhizoma Anemarrhenae extract on glucose and lipid metabolism in diabetic mice,and provide basis for follow-up research.Methods:The method of streptozotocin combined with high-fat diet was used to replicate the diabetes model in this study.After continuous intragastric administration for 6 weeks,the effects of Rhizoma Anemarrhenae extract on body weight,blood sugar,blood lipids,serum insulin and the organ index in diabetic mice were detected.Results:The fasting blood glucose and blood lipids(serum total cholesterol,triglyceride,low density lipoprotein cholesterol levels)of the Rhizoma Anemarrhenae group of mice were significantly decreased,which was statistically significant compared with the model group.The area under the curve of the Rhizoma Anemarrhenae group is significantly smaller than that of the model group,and the result is statistically significant.Rhizoma Anemarrhenae can increase serum insulin levels in diabetic mice,which is statistically significant compared with the model group.Compared with the model group,the liver,spleen,kidney and pancreas indexes of the Rhizoma Anemarrhenae group are significantly reduced.Conclusion:The extract of Rhizoma Anemarrhenae can significantly reduce blood glucose concentration,lower blood lipid levels,promote serum insulin secretion,and protect liver,kidney,spleen,pancreas and other tissues and organs.

Carbon dots-based fluorescence sensor for two-photon imaging of pH in diabetic mice

Herein,a reversible pH fluorescent sensor was developed using caffeic acid as the precursor by one-step solvothermal synthesis method.The carbon dots-based sensor(CA-CDs)exhibited pH-dependent increase in fluorescence intensity and showed linear relationship in the range of pH 6.60 and 8.00.Notably,the fluorescence sensor has a reversible response to pH change.Finally,the CA-CDs has been successfully applied for two-photon imaging of the pH in liver and kidney of diabetic mice.Imaging results showed that the pH value in kidney of diabetic mice was lower than that of the normal mice,while the pH value in liver of diabetic mice was almost the same as that of the normal mice.The present study provides a simple analytical method for pH detection suitable for in vivo.

Integrated metabolomics analysis of the effect of PPARδ agonist GW501516 on catabolism of BCAAs and carboxylic acids in diabetic mice

The peroxisome proliferator-activated receptor(PPARδ)agonists are reported to improve insulin sensitivity,reduce glucose levels,and alleviate dysfunctional lipid metabolism in animal models of type 2 diabetes mellitus.However,the underlying mechanisms remain incompletely understood.Metabolism plays an essential role in the biological system.Monitoring of metabolic changes in response to disease conditions or drug treatment is critical for better understanding of the pathophysiological mechanisms.In this study,metabolic profiling analysis by gas chromatography-mass spectrometry integrated with targeted analysis by liquid chro matography-mass spectrometry was carried out in plasma samples of db/db diabetic mice after six-week treatment of PPARδagonist GW501516.GW501516 treatment significantly altered levels of metabolites,such as branched-chain amino acids(BCAAs),BCAA metabolites(3-hydroxyisobutyric acid and 3-hydroxyisovaleric acid),long-chain fatty acids,uric acid and ketone bodies(3-hydroxybutyric acid and 2-hydroxybutyric acid)which are all associated with the impaired systemic insulin sensitivity.The pre sent results indicate the beneficial effect of PPARδagonist in alleviating insulin resistance of diabetic mice by favorably modulating metabolic profile,thus providing valuable information in understanding the therapeutic potential of PPARδagonists in correcting metabolic dysfunction in diabetes.

Hypolipidemic effect of chromium-modified enzymatic product of sulfated rhamnose polysaccharide from Enteromorpha prolifera in type 2 diabetic mice

Sulfated rhamnose polysaccharide(SRP)derived from Enteromorpha prolifera is a metal-ion chelating agent that could potentially be used to treat diabetes.The aim of our study was to determine the effect of a variant of SRP on DIABETES.First,we synthesized and characterized SRPE-3 chromium(III)[SRPE-3-Cr(III)]complex using an enzymatic method.The maximum chelation rate was 18.2%under optimal chelating conditions of pH 6.0,time 4 h,and temperature 60°C.Fourier transform infrared spectroscopy results showed important sites for Cr(III)-binding were O–H and C=O groups.We then studied the hypolipidemic effects of SRPE-3-Cr(III)on type 2 diabetes mellitus(T2DM)induced by a high-fat,high-sucrose diet(HFSD).Decreased blood glucose content,body fat ratio,serum TG,TC,LDL-C,and increased serum HDL-C were observed after treatment with SRPE-3-Cr(III).In addition,SRPE-3-Cr(III)significantly reduced leptin,resistin,and TNF-αlevels,and increased adiponectin contents relative to T2DM.Histopathology results also showed that SRPE-3-Cr(III)could alleviate the HFSD-lesioned tissues.SRPE-3-Cr(III)also improved lipid metabolism via a reduction in aspartate aminotransferase,alanine aminotransferase,fatty acid synthase,and acetyl-CoA carboxylase activities in the liver.SRPE-3-Cr(III)at low doses exhibited better lipid-lowering activities,hence,could be considered to be a novel compound to treat hyperlipidemia and also act as an anti-diabetic agent.

Protective Effects of Leukemia Inhibitory Factor on Retinal Vasculature and Cells in Streptozotocin-induced Diabetic Mice

Background： Leukemia inhibitory factor （LIF） has been reported to possess various pharmacological effects, including displaying vascular and neuroprotective properties, during retinal disease. The aim of this study was to investigate the vascular and structural changes in the retina of diabetic mice and to explore whether LIF prevents experimental diabetes-induced retinal injury in the early stages. Methods： Diabetes was induced in C57BI/6J mice with streptozotocin （STZ） injections. Successful diabetic animal models were randomly separated into two groups： the diabetic group （n = 15） and the LIF-treated group （n = 15）. Normal C57BL/6 mice served as the normal control group （n = 14）. Recombinant human LIF was intravitreally injected 8 weeks after the diabetic model was successfully established. Retinas were collected and evaluated using histological and immunohistochemical techniques, and flat-mounted retinas and Western blotting were performed at 18 weeks after the induction of diabetes and 2 days after the intravitreal injection of LIF. The analysis of variance test were used. Results： Histological analysis showed that there were fewer retinal ganglion cells （RGCs） and the inner nuclear layer （INL） became thinner in the diabetic model group （RGC 21.8 ± 4.0 and INL 120.2 ± 4.6 μm） compared with the normal control group （RGC 29.0 ± 6.7, t = -3.02, P = 0.007; INL 150.7 ±10.6 lain, t = -8.88, P 〈 0.001, respectively）. After LIF treatment, the number of RGCs （26.9 ± 5.3） was significantly increased （t = 3.39, P = 0.030） and the INL （ 134.5± 14.2 lain） was thicker compared to the diabetic group （t - 2.75, P = 0.013）. In the anti-Brn-3a-labeled retinas, the number of RGCs in the LIF-treated group （3926.0 ± 143.9） was obviously increased compared to the diabetic group （3507.7 ± 286.1, t = 2.38, P = 0.030）, while no significance was found between the LIF-treated group and the control group （4188.3 ± 114.7, t= -2.47, P- 0.069）. Flat-mounted retinas demonstrated that a disorganized, dense distribution of the vessel was prominent in the diabetic model group. Vessel distribution in the LIF-treated mouse group was typical and the thickness was uniform. The levels of phosphosignal transducer and activator of transcription 3 activation were obviously higher in the LIF-injected retinas than those in the diabetic control group （t = 3.85, P = 0.019） and the normal control （t = -3.20, P - 0.019）. Conclusion： The present study provides evidence that LIF treatment protects the integrity of the vasculature and prevents retinal injury in the early stages of diabetic retinopathy in STZ-induced diabetic models.

EFFECTS AND MECHANISM OF SANGGUA DRINK ON BLOOD GLUCOSE IN DIABETIC MICE INDUCED BY STREPTOZOTOCIN

Sanggua Drink(SGD)consists of Momordica charantia,Mulberry leaves,Pueraria lobata and Dioscorea opposzite.It has been extensively prescribed owing to notable medicinal benefits.This article aims to investigate the hypoglycemic mechanism of SGD in diabetic mice.Streptozotocin-induced diabetic mice were divided into five groups:normal control group,model group,SGD water extraction group。

Sialoadenitis progression in nonobese diabetic mice and its correlation with expression of apoptosis-associated proteins in salivary glands and serum IgG levels

Background Sjogren syndrome （SS） is an autoimmune disorder characterized by chronic lymphocytic infiltration and decreased secretion in salivary glands. Apoptosis is one of the possible mechanisms involved in acinar epithelial destruction in SS. The role of apoptosis in the initiation and effect phase of sialoadenitis is still controversial. The aim of this study was to observe the roles of apoptosis-associated proteins and serum IgG levels in sialoadenitis progression in nonobese diabetic （NOD） mice. Methods 2-, 5-, 10-, 15-, 20-week female NOD and matched BALB/c control mice were selected. Saliva and tear flow rate were measured. Serum IgG level was tested by enzyme-linked immunosorbent assay （ELISA）. Number of lymphocyte foci （NLF） in submandibular glands （SMGs） was counted under routine hematoxylin/eosin-stained sections. Expression of Fas, Bcl-2 and procaspase3 proteins as well as apoptotic cells in the SMGs were detected by immunohistochemical staining and by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling （TUNEL） assay respectively. Results Decreased stimulated total flow rate （STFR） and lymphocyte foci in SMGs were first observed in the 10-week NOD group. STFR was negatively correlated with NLF （P〈0.05）. Serum IgG in NOD mice was significantly higher than that of the control group （P〈0.05） and showed a positive correlation with NLF （P〈0.05）. Fas expression in SMGs acinar cells in NOD mice increased with age and was significantly higher compared with that in the control group. Bcl-2 expression and procaspase3 expression in SMG acinar cells in each NOD group were lower compared with those of the age-matched control mice. Conclusion Abnormal expression of Fas and Bcl-2 in the SMGs and higher level of serum IgG may contribute to the initiation of sialoadenitis and cause the glandular destruction in NOD mice.

Expression and role of P-element-induced wimpy testis-interacting RNA in diabetic-retinopathy in mice

BACKGROUND As one of the major microvascular complications of diabetes,diabetic retinopathy(DR)is the leading cause of blindness in the working age population.Because the extremely complex pathogenesis of DR has not been fully clarified,the occurrence and development of DR is closely related to tissue ischemia and hypoxia and neovascularization The formation of retinal neovascularization(RNV)has great harm to the visual acuity of patients.AIM To investigate the expression of P-element-induced wimpy testis-interacting RNA(piRNA)in proliferative DR mice and select piRNA related to RNV.METHODS One hundred healthy C57BL/6J mice were randomly divided into a normal group as control group(CG)and proliferative DR(PDR)group as experimental group(EG),with 50 mice in each group.Samples were collected from both groups at the same time,and the lesions of mice were evaluated by hematoxylin and eosin staining and retinal blood vessel staining.The retinal tissues were collected for second-generation high-throughput sequencing,and the differentially expressed piRNA between the CG and EG was detected,and polymerase chain reaction(PCR)was conducted for verification.The differentially obtained piRNA target genes and expression profiles were enrichment analysis based on gene annotation(Gene Ontology)and Kyoto Encyclopedia of Genes and Genomes.RESULTS In the CG there was no perfusion area,neovascularization and endothelial nucleus broke through the inner boundary membrane of retinap.In the EG,there were a lot of nonperfused areas,new blood vessels and endothelial nuclei breaking through the inner boundary membrane of the retina.There was a statistically significant difference in the number of vascular endothelial nuclei breaking through the inner retinal membrane between the two groups.High-throughput sequencing analysis showed that compared with the CG,a total of 79 piRNAs were differentially expressed in EG,among which 43 piRNAs were up-regulated and 36 piRNAs were down-regulated.Bioinformatics analysis showed that the differentially expressed piRNAs were mainly concentrated in the signaling pathways of angiogenesis and cell proliferation.Ten piRNAs were selected for PCR,and the results showed that the expression of piR-MMU-40373735,piRMMU-61121420,piR-MMU-55687822,piR-MMU-1373887 were high,and the expression of piR-MMU-7401535,piR-MMU-4773779,piR-MMU-1304999,and piR-MMU-5160126 were low,which were consistent with the sequencing results.CONCLUSION In the EG,the abnormal expression of piRNA is involved in the pathway of angiogenesis and cell proliferation,suggesting that piRNAs have some regulatory function in proliferative diabetic-retinopathy.

Metabolite profiling and antidiabetic attributes of ultrasonicated leaf extracts of Conocarpus lancifolius

Objective:To profile the secondary metabolites and to evaluate the antidiabetic potential of hydroethanolic leaf extracts of Conocarpus lancifolius.Methods:The various hydroethanolic extracts of Conocarpus lancifolius leaf were prepared by ultrasonication assisted freezedrying.Total phenolic contents,flavonoid contents,antioxidant activity,α-glucosidase andα-amylase inhibitions of leaf extracts were determined.The metabolite profiling was accomplished by UHPLC-Q-TOF-MS/MS analysis.The antidiabetic assessment of the most potent extract was carried out by measuring the hypoglycemic and hypolipidemic effect in the high fat diet-fed diabetic albino mice.The blood glucose level,haemoglobin,total cholesterol,high-density lipoproteins(HDL)and low-density lipoproteins(LDL)were determined.Results:The 60%ethanolic extract exhibited the highest phenolic and flavonoid contents of(349.39±2.13)mg GAE/g dry extract and(116.95±2.34)mg RE/g dry extracts,respectively,and the highest DPPH scavenging activity with an IC50 value of(32.87±1.11)μg/mL.The IC50 values forα-glucosidase andα-amylase inhibitions were(38.64±0.93)μg/mL and(44.80±1.57)μg/mL,respectively.UHPLC-Q-TOF-MS/MS analysis confirmed the presence of gallic acid,ellagic acid,corilagin,kaempherol-3-O-rutinoside,caffeic acid derivative,isorhamnetin and galloyl derivatives in the 60%ethanolic extract.Plant extract at a dose of 450 mg/kg body weight reduced blood glucose level,total cholesterol,LDL and HDL,and increased haemoglobin in alloxan-induced diabetic mice,Conclusions:Conocarpus lancifolius leaves are proved as a good source of biologically functional metabolites and possess antidiabetic activity which may be further explored to treat diabetes.

Study on the hypolipidemic properties of garlic polysaccharide in vitro and in normal mice as well as its dyslipidemia amelioration in type2 diabetes mice

In the present work,garlic polysaccharide(GP)in lowering lipid based on in vitro and in vivo approaches were investigated.The in vitro studies revealed significant effects of GP on cholesterol,sodium cholate,oil binding,and lipase inhibition.Meanwhile,the liver index in the medium and high dose GP group was significantly lower than the control group in normal mice which relatively corresponded to the modulated effect of intestinal flora.A high dose of GP has markedly reduced the ratio of intestinal Firmicutes to Bacteroidetes and increased the abundance of gut probiotics Akkermansia.Furthermore,the high dose of GP also significantly reduced the levels of triglyceride and low-density lipoprotein cholesterol of diabetic mice indicating that GP could not only prevent hyperlipidemia of metabolic syndrome but also further ameliorate dyslipidemia of diabetes mellitus.This study provides new prospects for garlic polysaccharide as a hypolipidemic nutraceutical for the treatment of metabolic syndrome and type 2 diabetes.

Bulk-like endocytosis plays an important role in the recycling of insulin granules in pancreatic beta cells

Although bulk endocytosis has been found in a number of neuronal and endocrine cells,the molecular mechanism and physiological function of bulk endocytosis remain elusive.In pancreatic beta cells,we have observed bulk-like endocytosis evoked both by flash photolysis and trains of depolarization.Bulk-like endocytosis is a clathrin-independent process that is facilitated by enhanced extracellular Ca^(2+) entry and suppressed by the inhibition of dynamin function.Moreover,defects in bulklike endocytosis are accompanied by hyperinsulinemia in primary beta cells dissociated from diabetic KKAy mice,which suggests that bulk-like endocytosis plays an important role in maintaining the exo-endocytosis balance and beta cell secretory capability.