The Goto-Kakizaki (GK) rat is a spontaneous type 2 diabetic animal model, which is characterized by a progressive loss of beta islet cells with fibrosis. In the present study, the hypoglycemic effect of asiatic acid (AA) in GK rats was examined. GK rats receiving AA at a daily dose of 25 mg·kg(-1) for four weeks showed a significant reduction in blood glucose levels. Age-matched normal Wistar rats were given 0.5% sodium carboxymethyl cellulose (CMC-Na) solution for the same periods and used as control. Compared to the normal Wistar rats, GK rats treated with AA showed improvement in insulin resistance partially through decreasing glucose level (P < 0.01) and insulin level (P < 0.05). Furthermore, the results of immunohistochemistry indicate that AA treatment reduced islet fibrosis in GK rats. Fibronectin, a key protein related to islet fibrosis, was over-expressed in GK rats, which was reversed significantly by AA treatment (P < 0.05). These findings suggest that AA has a beneficial effect on lowering blood glucose levels in GK rats and improves fibrosis of islets in diabetes, which may play a role in the prevention of islets dysfunction.
Animals ; Blood Glucose ; metabolism ; Centella ; chemistry ; Diabetes Mellitus, Type 2 ; drug therapy ; pathology ; Disease Models, Animal ; Fibronectins ; metabolism ; Fibrosis ; Glucose Tolerance Test ; Hyperglycemia ; drug therapy ; pathology ; Insulin ; blood ; Insulin Resistance ; Islets of Langerhans ; drug effects ; pathology ; Male ; Pancreatic Diseases ; metabolism ; pathology ; prevention & control ; Pentacyclic Triterpenes ; pharmacology ; therapeutic use ; Phytotherapy ; Plant Extracts ; pharmacology ; therapeutic use ; Rats, Inbred Strains

OBJECTIVETo study the effect of total saponins from Entada phaseoloides (TSEP) on islet morphology and skeletal muscle PI3K pathway-related protein expression of type 2 diabetic rats.

METHODType 2 diabetic rats were induced by high-fat diet and low-dose streptozotocin and then randomly divided into 5 groups, i.e. the normal control, the model group, the positive control drug (200 mg x kg(-1) metformin), the low-dose TSEP (25 mg x kg(-1)) group and the high-dose TSEP (50 mg x kg(-1)). Three weeks later, the islet morphology of rat pancreas were observed by HE staining, and protein expressions of insulin receptor substrate-1 (IRS-1), phosphatidylinositol 3-kinase (PI3K), protein tyrosine phosphatase-1B (PTP-1 B) and glucose transporter 4 (GLUT4) in rat skeletal muscle were detected by Western blot.

RESULTCompared with the modal group, TSEP administration groups showed relatively normal structures, clear pancreatic cells and intact capsula structures in pancreatic tissue pathological sections, with the number of pancreatic islets close to the normal control group. Meanwhile, above TSEP administration groups showed increased IRS-1, PI3K and GLUT4 protein expressions in their skeletal muscle tissues and decreased PTP-1B protein expression compared with the model group.

CONCLUSIONTSEP has an effect on protecting pancreatic tissues of type 2 diabetic rats and intervening in abnormal expression of proteins in skeletal muscle tissues.

Animals ; Diabetes Mellitus, Type 2 ; drug therapy ; Fabaceae ; chemistry ; Glucose Transporter Type 4 ; analysis ; Islets of Langerhans ; drug effects ; pathology ; Male ; Muscle, Skeletal ; drug effects ; pathology ; Phosphatidylinositol 3-Kinases ; analysis ; Rats ; Rats, Sprague-Dawley ; Saponins ; therapeutic use

This study is to observe anti-lipotoxic effect of sesamin on renovascular hypertensive rats fed with a high-fat, high-sucrose diet. Thirty-four complex model rats were induced by two-kidney, one-clip method and on high-fat and refined-carbohydrate diet for thirteen weeks. From the fifth week, intragastric administration of sesamin (120, 60 and 30 mg x kg(-1) x d(-1)) lasted for eight weeks. Blood pressure (BP), blood fat (BF), blood glucose (BG), free fatty acids (FFA), insulin (Ins), tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 were determined. Pathological changes of pancreas, perirenal fat and liver were semiquantitatively analyzed. In sesamin (120 and 60 mg x kg(-1) x d(-1)) group, it was found that there were decrease of levels of BP, BF, BG, TNF-alpha, IL-6 and FFA, improvement of insulin resistance and glucose tolerance, alleviation of body weight, humid weight of fat, liver and pancreas and their organ index, and reduction of islet cell hyperplasia and amount of lipid droplet vacuoles in lipocyte and hepatocyte. It is implied that sesamin had anti-lipotoxic effect and its mechanism may be closely associated with the amelioration of insulin resistance via reducing lipidoses in hepatocyte and inflammatory adipokines such as TNF-alpha and IL-6.
Adipocytes ; drug effects ; Animals ; Anticholesteremic Agents ; administration & dosage ; pharmacology ; Antihypertensive Agents ; administration & dosage ; pharmacology ; Blood Glucose ; metabolism ; Blood Pressure ; drug effects ; Body Weight ; drug effects ; Cholesterol ; blood ; Diet, High-Fat ; Dioxoles ; administration & dosage ; pharmacology ; Dose-Response Relationship, Drug ; Fatty Acids, Nonesterified ; blood ; Glucose Tolerance Test ; Hypertension, Renovascular ; blood ; pathology ; Insulin ; blood ; Insulin Resistance ; Interleukin-6 ; blood ; Islets of Langerhans ; pathology ; Lignans ; administration & dosage ; pharmacology ; Liver ; pathology ; Male ; Pancreas ; pathology ; Rats ; Rats, Sprague-Dawley ; Sucrose ; Triglycerides ; blood ; Tumor Necrosis Factor-alpha ; blood

To investigate the semi-quantitative method for evaluating the lipid accumulation in pancreas, the KKAy mice, a classical type 2 diabetes mellitus model mice, were used and treated with rosiglitazone (Rosi); and the age-matched C57BL/6J mice were used as normal control. Pancreas was fixed quickly for histological examination with HE staining. For the estimation of the lipid accumulation in pancreas, semi-quantitative method was designed: the number and the size of islet, lipid accumulation in islet and in exocrine gland were observed and the integrative score calculated under the microscope, separately. In KKAy mice, the characteristics of the increased amount of islet, the enlarged area of islet, an abundance of large vacuolations, lipid droplets, and fat proliferation were exposed frequently, and the integrative score increased 2.1 folds compared with that in C57BL/6J mice. Meanwhile, the levels of serum glucose, insulin, and triglyceride (TG) were 1.7, 18.0, and 9.0 times as those in C57BL/6J mice, respectively. With the rosiglitazone (10 mg x kg(-1)) treatment, compared with that in KKAy mice, the pancreatic pathological changes were ameliorated significantly, and the integrative score in KKAy + Rosi mice decreased by 28.9%; and the levels of serum glucose, insulin, and triglyceride decreased by 48.3%, 81.3% and 64.1%, respectively. It showed there is a correlation between the pancreatic pathological semi-quantitative score and the values of serum parameters. In conclusion, this semi-quantitative scoring method is simple and objective for the evaluation of lipid accumulation in pancreas of mice.
Animals ; Blood Glucose ; metabolism ; Diabetes Mellitus, Type 2 ; blood ; metabolism ; pathology ; Female ; Hypoglycemic Agents ; pharmacology ; Insulin ; blood ; Islets of Langerhans ; metabolism ; pathology ; Lipid Metabolism ; drug effects ; Mice ; Mice, Inbred C57BL ; Pancreas ; metabolism ; pathology ; Random Allocation ; Thiazolidinediones ; pharmacology ; Triglycerides ; blood

OBJECTIVETo study the effects of a self-formulated blood glucose-adjusting recipe on blood glucose and pathology of the pancreas in diabetic mice.

METHODSDiabetes mellitus (DM) was induced in mice by injection of alloxan through the caudal vein. The blood glucose-adjusting recipe was administered in the mice at the doses of 20, 10 and 5 g/kg for 21 days, after which blood glucose was determined and the sugar tolerance was evaluated, and the pancreas and islet pathologies were examined microscopically.

RESULTSThe blood glucose-adjusting recipe at 20 g/kg significantly lowered the fast blood glucose in the mice, and at 20 and 10 g/kg, the recipe significantly lowered the blood glucose 2 h after glucose administration and increased the sugar tolerance. The pathological damage in the diabetic mice was alleviated after treatment with the recipe.

CONCLUSIONSThe blood glucose-adjusting recipe has a good effect in stabilizing blood glucose in mice.

Animals ; Blood Glucose ; drug effects ; Diabetes Mellitus, Experimental ; blood ; drug therapy ; pathology ; Drugs, Chinese Herbal ; therapeutic use ; Islets of Langerhans ; pathology ; Mice ; Phytotherapy

Nonspecific inflammatory response is the major cause for failure of islet grafts at the early phase of intraportal islet transplantation (IPIT). Bilirubin, a natural product of heme catabolism, has displayed anti-oxidative and anti-inflammatory activities. The present study has demonstrated that bilirubin protected islet grafts by inhibiting nonspecific inflammatory response in a syngeneic rat model of IPIT. The inflammation-induced cell injury was mimicked by exposing cultured rat insulinoma INS-1 cells to cytokines (IL-1beta, TNF-alpha and IFN-gamma) in in vitro assays. At appropriate lower concentrations, bilirubin significantly attenuated the reduced cell viability and enhanced cell apoptosis induced by cytokines, and protected the insulin secretory function of INS-1 cells. Diabetic inbred male Lewis rats induced by streptozotocin underwent IPIT at different islet equivalents (IEQs) (optimal dose of 1000, and suboptimal doses of 750 or 500), and bilirubin was administered to the recipients every 12 h, starting from one day before transplantation until 5 days after transplantation. Administration of bilirubin improved glucose control and enhanced glucose tolerance in diabetic recipients, and reduced the serum levels of inflammatory mediators including IL-1beta, TNF-alpha, soluble intercellular adhesion molecule 1, monocyte chemoattractant protein-1 and NO, and inhibited the infiltration of Kupffer cells into the islet grafts, and restored insulin-producing ability of transplanted islets.
Animals ; Apoptosis/drug effects/immunology ; Bilirubin/*administration & dosage/pharmacology ; Cell Line, Tumor ; Cytokines/immunology/metabolism ; Diabetes Mellitus, Experimental/*drug therapy/*immunology ; Inflammation ; Inflammation Mediators/immunology/metabolism ; Islets of Langerhans/drug effects/*immunology/injuries/pathology ; *Islets of Langerhans Transplantation ; Male ; Oxidative Stress/drug effects/immunology ; Rats ; Rats, Inbred Lew ; Transplantation, I

AIMTo investigate the chronic effect of palmitic acid (PA) on apoptosis of pancreatic islet beta-cells and the possible mechanism.

METHODSInsulinoma cell line (MIN6 cells) were used in this study. After being incubated in PA (0.1 - 1.6 mml/L) for 24 and 48 hours, MTT method was used to evaluate the livability. After being incubated for 48 h, Hoechst-PI and Annexin-V-FTTC/PI FACS were used to estimate the apoptosis in each group, Western-blotting assay was used to estimate the protein level of p-Akt, Akt, Bax and Bcl-2.

RESULTSChronic PA dose-dependently (1) decreased the availability and increased the apoptosis of MIN6 cells; (2) decreased the phosphorylation of Akt and Bcl-2, but had no significant effects on Akt and Bax.

CONCLUSIONChronic PA dose-dependently induced apoptosis of MIN6 cells, and this effect was possibly regulated by Akt/Bcl-2.

Animals ; Apoptosis ; drug effects ; Cell Line, Tumor ; Cells, Cultured ; Insulinoma ; pathology ; Islets of Langerhans ; pathology ; Mice ; Oxidative Stress ; physiology ; Palmitic Acid ; pharmacology ; Proto-Oncogene Proteins ; metabolism ; Proto-Oncogene Proteins c-akt ; metabolism ; Proto-Oncogene Proteins c-bcl-2 ; Signal Transduction ; drug effects ; physiology ; bcl-2-Associated X Protein ; metabolism

OBJECTIVETo study the protective effect of islet xenograft and its possible mechanism of high expression of heme oxygenase-1 (HO-1) in donor pancreas islet induced by cobalt protoporphyrin (CoPP).

METHODSMale SD rats and C57BL/6 mouse were used as donors and recipients respectively. Donors were divided into 3 groups according to different pretreatment 24 hours before donation: control group (injected intraperitoneally with NaCl), induce group [injected intraperitoneally with cobalt-protoporphyrin (CoPP)], block group (injected intraperitoneally with CoPP and zinc protoporphyrin simultaneously). A modified approach was used for islet isolation.Recipients were rendered diabetic by intraperitoneal injection of streptozotocin. Islets were transplanted into mouse subrenal capsule. Postoperative mouse glycemia were monitored daily and normoglycemia time was compared among each group. The receptor mouse serum IL-10 was detected by ELISA approach, and real-time PCR was used to check the expression of IL-10 mRNA in islet graft tissues. The graft tissues were observed for the lymphocyte infiltration after HE staining.

RESULTSDiabetes mice accepted islets untreated, induced or blocked maintained the euglycemia for (9.3 +/- 1.4), (16.3 +/- 1.5) and (9.7 +/- 1.0) d respectively. The xeno-islets presented HO-1 over-expression survived much longer than that absent (P < 0.05), it was no significance between control group and block group (P > 0.05). The mouse islet serum IL-10 content after induction was (73.0 +/- 9.7) pg/ml, significantly higher than (30.6 +/- 3.9) pg/ml of the untreated group and (32.1 +/- 5.9) pg/ml of the blocked group (P < 0.05), there was no difference between control group and block group (P > 0.05). Moreover, the IL-10 mRNA expression up-regulated statistic significantly in HO-1 induced islet xeno-graft. Pathological examination showed that the graft lymphocyte infiltration of the induced group was obviously less serious than the other two groups.

CONCLUSIONSThe higher expression of HO-1 induced by CoPP in vivo would significantly prolong graft survival time and its mechanism could be related to immune modulation of IL-10.

Animals ; Diabetes Mellitus, Experimental ; metabolism ; pathology ; surgery ; Graft Survival ; Heme Oxygenase-1 ; drug effects ; metabolism ; Interleukin-10 ; metabolism ; Islets of Langerhans ; metabolism ; pathology ; Male ; Mice ; Mice, Inbred C57BL ; Pancreas Transplantation ; Protoporphyrins ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Subrenal Capsule Assay ; Transplantation, Heterologous

OBJECTIVETo explore the effect of Jiangtang Xiaozhi capsule (JXC) on morphological changes of islets and liver at rat model of type 2 diabetic mellitus and provide the experimental basis for the clinical therapy of type 2 diabetic mellitus.

METHODWister rats were fed on a diet enriched in fat and glucose to induce insulin resistan, the rats were injected intrapertoneally with a low-dose streptozotocin (STZ) twice (25 mg x kg(-1)) to induce hyperglycemia, so the successful rat model of type 2 diabetes were established. The experimental rats were divided into model group, high dose JXC group, middle dose JXC group, low dose JXC group, Erjiashuanggua group, Jinqijiangtang group and normal control group. After all the treatment groups received their own medicine for two months, all the rats were sacrificed and morphological examination on their islets and livers were performed.

RESULTFatty liver in various degrees was seen in the model group and all the treatment groups, but the liver steatosis in middle and low dose JXC groups was significantly milder than that in model group (P < 0.05). Islets in the high dose JXC group were significantly more than that in the model group (P < 0.05).

CONCLUSIONJXC can improve significantly the pathological change in islets and liver steatosis at rat model of type 2 diabetic mellitus.

Animals ; Diabetes Mellitus, Experimental ; drug therapy ; pathology ; Drugs, Chinese Herbal ; pharmacology ; Female ; Islets of Langerhans ; drug effects ; pathology ; Liver ; drug effects ; pathology ; Male ; Microscopy ; Rats ; Rats, Wistar

Pancreatic islet transplantation can correct the abnormal glucose metabolism of Type 1 diabetes. Although immunosuppressants greatly reduce the acute rejection rate in transplant patients, the long-term side effects can be debilitating. Therefore, researchers are seeking to develop new immunosuppressive regimens that induce maximal levels of immunosuppression with minor side effects. Rosmarinic acid (Ros A) is a secondary metabolite of certain herbs and has multiple biological activities, including anti-inflammatory effects. Here, we have investigated whether treatment of mice with a combination of Ros A and anti-CD154 monoclonal antibody (MR1) improves islet allograft survival in a murine model. After transplantation, the mice were treated with either Ros A, MR1, or both (the "double" treatment). Allograft survival was prolonged in the double-treated animals compared to animals that received only Ros A or MR1. As is the case with the single-treated animals at 15 days after transplantation, the double-treated recipients did not display a significant decrease in the expression of cytokines or the population of activated T cells. Infiltrating CD3+ T cells were reduced in the MR1- or double therapy relative to control or RosA group. However, at the same time point, double-treated graft showed fewer apoptotic cells and increased expression of insulin and glucagons, compared to the single-treatment groups. Furthermore, long-term (>150 days) allografts that were received with double therapy exhibited larger islet clusters and contained more insulin- and glucagon-positive cells, relative to the MR1-treated grafts. In conclusion, treatment with both Ros A and MR1 has a synergistic effect in murine islet allotransplantation.
Animals ; Antibodies, Monoclonal/*pharmacology ; Apoptosis/drug effects ; CD40 Ligand/*immunology ; Cinnamates/*pharmacology ; Cytokines/biosynthesis ; Depsides/*pharmacology ; Diabetes Mellitus, Experimental ; Flow Cytometry ; Glucose/metabolism ; Glucose Tolerance Test ; Graft Survival/*drug effects ; In Situ Nick-End Labeling ; Injections, Intraperitoneal ; Islets of Langerhans/drug effects/pathology ; *Islets of Langerhans Transplantation ; Male ; Mice ; Mice, Inbred BALB C ; Mice, Inbred C57BL ; Time Factors ; Transplantation, Homologous