OBJECTIVETo establish a new gastric bypass animal-model with Goto-Kakizaki rats whose different parts of the small intestine were bypassed while stomach was not bypassed.

METHODSForty male 3-month-old GK rats were randomly divided into 4 groups: group I (sham operation), group II (duodenum bypassed), group III (jejunum bypassed), group IV (ileum bypassed). Fasting plasma glucose was measured before operation and the 1st, 4th,and 8th week after operation in all the rats, the body weight of all the rats were measured simultaneously.

RESULTSThe survival rate of operation for the rats was 95%. Two rats in group IV (died on the first day after operation. The mean fasting plasma glucose concentration of the rats in group II, III, IV (declined obviously 4 weeks after gastric bypass [group II (12.02+/-1.97) vs (6.36+/-0.50) mmol/L, group III (13.42+/-1.66) vs (5.96+/-0.53) mmol/L, group IV (14.32+/-2.82) vs (5.18+/-0.49) mmol/L, all P <0.01], but there were no significant differences among the gastric bypassed groups. The weight of rats in group I, II, III (increased obviously after gastric bypass [group I (253.6+/-9.37) vs (367.0+/-23.70) g, group II (268.2+/-7.95) vs (384.8+/-16.12) g, group III (253.0+/-6.20) vs (323.0+/-16.40) g, all P <0.05] except the rats in group IV ([(262.0+/-13.47) vs(185.8+/-11.56) g].

CONCLUSIONSThe mean fasting plasma glucose concentration of the GK rats decreases obviously after gastric bypass through different parts of small intestine. The fasting plasma glucose concentration is not associated with the length of small intestine and body weight.

Animals ; Blood Glucose ; analysis ; Diabetes Mellitus, Experimental ; surgery ; Diabetes Mellitus, Type 2 ; surgery ; Gastric Bypass ; Male ; Models, Animal ; Rats ; Rats, Inbred Strains

OBJECTIVETo investigate the effects of gastric bypass surgery(GBP) on hepatic phosphoenolpyruvate carboxykinase(PEPCK) mRNA expression in type 2 diabetic Goto-Kakizaki rats.

METHODSMale GK rats were randomized into three groups: gastric bypass surgery(n=10), sham operation with diet restriction(n=10), and sham operation alone(n=10). Liver specimens of GK rats were collected during the intraoperative period for self-control study and 8 weeks after surgery. Fasting blood glucose, food intake, and body weight were recorded before surgery and 1, 2, 4, 8 weeks after surgery. The expression of PEPCK mRNA was measured by real-time PCR.

RESULTSThe fasting plasma glucose level decreased from(17.6±2.1) mmol/L before surgery to(7.5±0.9) mmol/L 8 weeks after surgery in GBP group. The level of PEPCK mRNA decreased from 1.08±0.38 before surgery to 0.41±0.10 8 weeks after surgery, significantly lower than that in sham operation alone group(1.04±0.12)(P<0.01). The level of PEPCK mRNA in diet restriction group increased from 1.15±0.16 before surgery to 2.54±0.82 8 weeks after surgery(P<0.01). The expression of PEPCK mRNA in diet restriction was significantly higher than that in CBP group(P<0.01).

CONCLUSIONSGBP can significantly improve hyperglycemia in type 2 diabetic GK rat models, which may be associated with the decrease of hepatic PEPCK mRNA level.

Animals ; Blood Glucose ; analysis ; Diabetes Mellitus, Experimental ; enzymology ; surgery ; Diabetes Mellitus, Type 2 ; enzymology ; surgery ; Gastric Bypass ; Intracellular Signaling Peptides and Proteins ; genetics ; metabolism ; Liver ; enzymology ; Male ; Phosphoenolpyruvate Carboxykinase (GTP) ; genetics ; metabolism ; RNA, Messenger ; genetics ; Rats

OBJECTIVETo investigate the influence and significance of gastric bypass surgery on hepatic gluconeogenesis in type 2 diabetic Goto Kakizaki(GK) rats.

METHODSForty GK rats were randomly divided into Roux-en-Y gastric bypass group(group A) and sham operation group(group B). Differences in glucose tolerance experiment(OGTT) at preoperative and postoperative 1, 2 and 4 weeks were compared and weight was recorded. Glycated hemoglobin levels were measured preoperatively and 4 weeks postoperatively. The animals were sacrificed 4 weeks after surgery and liver tissues were harvested to detect the relative expression of mRNA and protein of glucose 6 phosphatase(G-6-P) and phosphoenol pyruvate kinase(PEPCK) with RT-PCR and Western blot.

RESULTSFasting blood glucose levels were 6.5, 4.9, and 4.7 mmol/L in group A, and were 10.3, 10.4, and 12.5 mmol/L in group B, and the differences between two groups were statistically significant(P<0.05). The blood glucose level at 2 h after stomach lavage were 8.3, 6.4 and 5.5 mmol/L in group A, and were 21.4, 23.8 and 24.7 mmol/L in group B at postoperative 1, 2, 4 weeks, and the differences between two groups were statistically significant(P<0.05). The glycosylated hemoglobin at postoperative 4 weeks was(6.8±1.0)%, significantly lower than that in group B[(7.9±0.8)%, P<0.05]. Hepatic G-6-P and PEPCK mRNA relative expression at postoperative 4 weeks was reduced by 21.0% and 25.9% respectively as compared to group B, and the protein expression reduced as well. Immunohistochemistry showed that hepatic glycogen sedimentary in group A increased significantly.

CONCLUSIONThe relative mRNA and protein level of key enzymes of hepatic gluconeogenesis are significantly decreased after Roux-en-Y gastric bypass surgery and hepatic gluconeogenesis is reduced, which may be a potential mechanism of the decrease of blood glucose.

Animals ; Blood Glucose ; analysis ; Diabetes Mellitus, Experimental ; metabolism ; surgery ; Diabetes Mellitus, Type 2 ; metabolism ; surgery ; Gastric Bypass ; Gluconeogenesis ; Glucose-6-Phosphatase ; metabolism ; Glycated Hemoglobin A ; metabolism ; Intracellular Signaling Peptides and Proteins ; metabolism ; Liver ; enzymology ; Male ; Phosphoenolpyruvate Carboxykinase (GTP) ; metabolism ; Rats

OBJECTIVETo examine the renal function changes and mechanisms on rats with diabetes through a sleeve gastrectomy operation.

METHODSThirty-six rats were induced diabetes through injection of streptozotocin (STZ), and 30 of these diabetic rats that blood glucose levels at the midrange (blood sugar 17.88-23.65 mmol/L, mean: 20.32 mmol/L) were randomly assigned to the sleeve gastrectomy group, Sham-operation group and control group. The serum creatinine, lipid parameters were measured postoperatively. The 24 h urine volume obtained and urine albumin excretion rate (UAER) was calculated. Serum and urinary creatinine were examined and glomerular filtration rate (GFR) was counted. Kidney sections were stained with periodic acid-Schiff, and then the index of mesangial expansion was determined. The expression of synaptopodin for podocytes was also performed through the immunohistochemical procedure. A one-way ANOVA and t-test were performed to evaluate differences between groups and each other.

RESULTSOnly one rat of SG group died after operation. The GFR ((8.44 ± 2.10) ml · g⁻¹ · d⁻¹), 24 h UAER ((36.04 ± 11.10) mg/d), plasma lipids level (total cholesterol (1.66 ± 0.23) mmol/L, triglycerides (1.25 ± 0.17) mmol/L), kidney weight ((1.61 ± 0.06) g), the index of mesangial expansion ((6.14 ± 1.50)%) and synaptopodin expression ((20.44 ± 2.99)%) were improved in the SG group compared with the sham-operation group ((15.05 ± 3.01) ml · g⁻¹ · d⁻¹, (57.01 ± 11.34) mg/d, (2.15 ± 0.29) mmol/L, (1.65 ± 0.23) mmol/L, (1.93 ± 0.07) g, (11.32 ± 2.09)%, (10.34 ± 1.43)%) and control group ((14.79 ± 2.38) ml · g⁻¹ · d⁻¹, (62.71 ± 16.46) mg/d, (2.23 ± 0.21) mmol/L, (1.59 ± 0.20) mmol/L, (1.91 ± 0.06) g, (10.82 ± 1.79)%, (11.13 ± 2.43)%) (t = 0.781-5.025, all P < 0.05).

CONCLUSIONThe sleeve gastrectomy procedure can improve the renal function in a diabetes rat model may be through protecting the podocytes function and preventing the mesangial expansion of glomeruli.

Animals ; Blood Glucose ; Creatinine ; blood ; urine ; Diabetes Mellitus, Experimental ; physiopathology ; Diabetic Nephropathies ; physiopathology ; surgery ; Gastrectomy ; Glomerular Filtration Rate ; Kidney ; physiopathology ; Kidney Function Tests ; Random Allocation ; Rats

OBJECTIVETo observe the influence of negative pressure wound therapy on the angiogenesis of wounds in diabetic rats.

METHODSDiabetes model was reproduced by intraperitoneal injection of 20 g/L streptozotocin in the dosage of 65 mg/kg in 40 SD rats. Two weeks later, rats were divided into control group (C) and negative pressure group (NP) according to the random number table, with 20 rats in each group. A piece of full-thickness skin in the center of the back of each rat in the size of 2 cm×2 cm was excised to produce a wound. Immediately after injury, wounds in group C were given conventional dressing change; wounds in group NP were treated with continuous negative pressure (-16.0 kPa) therapy for four hours a day, which lasted for seven days. (1) Blood glucose and body weight of rats in two groups were respectively measured by glucose meter and electronic scale before treatment, and 1 and 2 week (s) after. (2) Wound blood flow was detected by laser Doppler perfusion imager before treatment and on post treatment day (PTD) 1, 3, 7, with 5 rats at each time point. (3) On PTD 3 and 7, respectively, five rats from each group were sacrificed. The wound tissue was excised and divided into two parts. The angiogenesis in the left part tissue was observed with immunohistochemical staining. The microvessel density was calculated. (4) The full-thickness skin excised before treatment and the right part tissue freeze on PTD 3 and 7 were collected. On PTD 1 and 14, wound tissue was excised in the above-mentioned method. The mRNA levels of the vascular endothelial growth factor (VEGF), vascular endothelial growth factor receptor 1 (Fit-1), angiopoietin 1 (Ang-1), Ang-2, and tyrosine kinase receptor 2 (Tie-2) were determined with real-time fluorescence quantification PCR. Data were processed with two-way analysis of variance or LSD-t test.

RESULTS(1) No significant difference was observed between two groups in blood glucose level and body weight as a whole or at each time point (with F values respectively 0.667, 0.176, t values from 0.311 to 0.707, P values all above 0.05). (2) The difference in the overall wound blood flow of rats between two groups was significant (F = 24.66, P < 0.05). On PTD 1, 3, 7, values of wound blood flow of rats in group NP were (179 ± 24), (219 ± 12), (192 ± 30) perfusion unit, significantly higher than those of rats in group C[(127 ± 16), (179 ± 8), (144 ± 17) perfusion unit, with t values respectively 3.71, 5.57, 2.77, P < 0.05 or P < 0.01]. (3) The difference in the overall microvessel density in the wound of rats between two groups was significant (F = 33.25, P < 0.05). On PTD 3, the microvessel density in the wound of rats in group NP was (80 ± 12) per 100-time visual field, which was significantly higher than that of group C[(38 ± 4) per 100-time visual field, t = 9.257, P < 0.05]. On PTD 7, the microvessel density in the wound of rats in two groups were close (t = 1.159, P > 0.05), but the vessels in group NP were regularly arranged with spacious lumen, while the vessels in group C were disorderly arranged with narrow lumen. (4) On PTD 1, 3, mRNA expression levels of VEGF, Fit-1, and Ang-1 in group NP were obviously higher than those in group C (with t values from 1.28 to 11.60, P values all below 0.01). On PTD 7, the mRNA expression level of Ang-1 (27.59 ± 3.55) in group NP was obviously higher than that in group C (19.87 ± 1.86, t = 7.23, P < 0.001), while the mRNA level of its antagonist Ang-2 (5.79 ± 0.61) in group NP was obviously lower than that in group C (17.62 ± 0.85, t = 19.88, P < 0.001). On PTD 3, 7, 14, mRNA levels of Tie-2 in group NP were obviously lower than those in group C (with t values from 8.92 to 15.60, P values all below 0.01).

CONCLUSIONSNegative pressure wound therapy may promote wound angiogenesis by enhancing the expression of Ang-1 and lowering the expression of Ang-2 in diabetic rats.

Angiopoietin-1 ; metabolism ; Angiopoietin-2 ; metabolism ; Animals ; Diabetes Mellitus, Experimental ; surgery ; Male ; Negative-Pressure Wound Therapy ; Neovascularization, Physiologic ; Rats ; Rats, Sprague-Dawley ; Wound Healing

OBJECTIVETo investigate the relationship between the type 1 diabetic rats residual islet function and postoperative glycemia of gastric bypass procedure (GBP).

METHODSIntraperitoneal injection of STZ was used to produce type 1 diabetic rat model. According to the level of serum glucose, rats were divided into two groups: group 1 (fasting glucose 16.7-22.0 mmol/L, n=42) and group 2 (fasting glucose>22.0 mmol/L, n=54). Half rats of group 1 and group 2 received GBP, which were OP1 group (n=21) and OP2 group (n=27). The normal control group included 20 Wistar rats. The fasting glycemia and fasting C-peptide (C-P) were tested at postoperative weeks 1, 2, 3, and pancreas pathological slices were examined 3 weeks after surgery under microscope.

RESULTSAfter GBP, the C-P was elevated and the glycemia was well controlled in OP1 group compared with group 1 (P<0.05). But the C-P was not significantly increased and the glycemia control was poor compared with group 2 (P>0.05). Pathological examination revealed that there were partial islets residual in pancrease of group 1, the islets were shown obvious hyperplasia in OP1 group after GBP. There were almost no islets residual in pancrease of group 2, and the islets were shown no obvious hyperplasia in OP2 group after GBP.

CONCLUSIONSResidual islet function determines the glycemia changes of type 1 diabetic rats after gastric bypass.

Animals ; Blood Glucose ; metabolism ; Diabetes Mellitus, Experimental ; metabolism ; physiopathology ; surgery ; Female ; Gastric Bypass ; Male ; Pancreas ; physiopathology ; Postoperative Period ; Rats ; Rats, Wistar

OBJECTIVETo obtain massive human pancreatic islets with modified techniques and evaluation of the islets for the clinical allo-transplantation to treat type I and II diabetes.

METHODS28 consecutive adult human pancreata were isolated with modified automated techniques. Islets were purified using continuous density gradient. The islet yield was counted with international standard known as islet equivalent (IEQ). The function of the isolated islets was evaluated by measuring DNA/insulin ratio, static glucose stimulating test in vitro and transplanting the islets into diabetic nude mice in vivo followed by abdominal glucose tolerance test and C peptide measurement.

RESULTSThe yield of 28 consecutive human pancreata isolations ranged from 5 000 to 1 030 000 IEQs/pancreas with the average of 291 635 IEQs/pancreas. The first 13 isolations yielded 49 123 IEQs/pancreas, 846 IEQs/g and, purity 87% in average. The remained 15 isolations after the modifications yielded 501 813 IEQs/pancreas, 7 003 IEQs/g and purity 89% in average. The results of in vitro SGS showed good response to the different glucose concentration. 34 diabetic nude mice were transplanted under the renal capsule with the freshly isolated islets. 29 out of 34 diabetic mice obtained normoglycemia within 12 hours and the glucose tolerance tests were near normal. Serum C peptide level of transplanted mice is close to that of the control group.

CONCLUSIONSMassive human islets can be isolated with the modified techniques. Quality assessment of these islets both in vitro and in vivo has indicated that these high quality human islets could be used for the clinical allogeneic islet transplantation.

Adult ; Animals ; Cell Separation ; methods ; Diabetes Mellitus, Experimental ; surgery ; Glucose ; Humans ; In Vitro Techniques ; Islets of Langerhans ; cytology ; drug effects ; physiology ; Islets of Langerhans Transplantation ; Mice ; Mice, Nude ; Transplantation, Heterologous

OBJECTIVETo investigate the effects of duodenal-jejunal bypass(DJB) and sleeve gastrectomy(SG) on the expression of liver glucokinase(GCK) in diabetic rats.

METHODSAnimal models of Goto-Kakizaki rats and Sprague-Dawley rats were established by DJB and SG. Results of fasting glycemia and insulin were compared. Liver tissue was harvested 8 weeks postoperatively.Quantitative real-time PCR and Western blot were used to detect liver GCK mRNA and protein expression after operation.

RESULTSFasting plasma glucose levels of DJB group and SG group in GK rats were markedly declined 3 day and 1, 2, 4, 6, 8 weeks postoperatively(all P <0.01), while Sham group only dropped 3 day and 1 week postoperatively, and there were no significant differences 2 weeks postoperatively(P >0.05). Fasting plasma glucose levels of each group in SD rats did not change after operation. In GK rats, GCK mRNA level (1.45 +/-0.29) and protein expression (494.25 +/-30.25) after DJB were higher than Sham group (1.05 +/-0.19 and 409.13 +/-26.86) and control group (1.04 +/-0.17 and 404.75 +/-30.90). GCK mRNA level and protein expression after SG were 0.65 +/-0.25 and 345.25 +/-28.13 respectively, which were significantly lower than those in control group(all P <0.01). All the groups in SD rats experienced similar GCK expression change.

CONCLUSIONBoth DJB and SG can decrease the plasma glucose levels of GK rats, while there are different effects on the expression of liver GCK.

Animals ; Blood Glucose ; analysis ; Diabetes Mellitus, Experimental ; metabolism ; surgery ; Digestive System Surgical Procedures ; methods ; Duodenum ; surgery ; Gastrectomy ; Glucokinase ; metabolism ; Jejunum ; surgery ; Liver ; metabolism ; Male ; Rats ; Rats, Inbred Strains ; Rats, Sprague-Dawley

OBJECTIVETo assess the metabolic consequences of pancreatic transplantation with portal venous drainage and systemic venous drainage in induced inbred rats with streptozocin.

METHODSPancreaticoduodenal transplantation was performed on 8 rats with the donor portal veins anastomosed to the recipient superior mesenteric vein and on 10 rats with the donor portal veins anastomosed to the recipient cava inferior vein. We measured the recipients' weight, urine and plasma glucose concentration, plasma insulin concentration at the beginning, and before and after transplantation. We used the euglycemi-hyperinsulinemic glucose clamp test and glucose infusion required as an index of insulin sensitivity.

RESULTSThe plasma glucose and insulin concentration recovered to normal after transplantation in the portal venous drainage group. The plasma insulin levels increased in the systemic venous group after transplantation. There was a difference in the glucose infusion required between the two groups.

CONCLUSIONThese data imply that portal venous drainage of the transplanted pancreas is an important factor in the determination of peripheral insulin sensitivity.

Anastomosis, Surgical ; Animals ; Blood Glucose ; metabolism ; Body Weight ; Diabetes Mellitus, Experimental ; blood ; surgery ; Insulin ; blood ; Insulin Resistance ; Male ; Pancreas Transplantation ; Portal Vein ; surgery ; Rats ; Rats, Wistar ; Vena Cava, Inferior ; surgery

Type 1 diabetes is an autoimmune disease caused by permanent destruction of insulin-producing pancreatic beta cells and requires lifelong exogenous insulin therapy. Recently, islet transplantation has been developed, and although there have been significant advances, this approach is not widely used clinically due to the poor survival rate of the engrafted islets. We hypothesized that improving survival of engrafted islets through ex vivo genetic engineering could be a novel strategy for successful islet transplantation. We transduced islets with adenoviruses expressing betacellulin, an epidermal growth factor receptor ligand, which promotes beta-cell growth and differentiation, and transplanted these islets under the renal capsule of streptozotocin-induced diabetic mice. Transplantation with betacellulin-transduced islets resulted in prolonged normoglycemia and improved glucose tolerance compared with those of control virus-transduced islets. In addition, increased microvascular density was evident in the implanted islets, concomitant with increased endothelial von Willebrand factor immunoreactivity. Finally, cultured islets transduced with betacellulin displayed increased proliferation, reduced apoptosis and enhanced glucose-stimulated insulin secretion in the presence of cytokines. These experiments suggest that transplantation with betacellulin-transduced islets extends islet survival and preserves functional islet mass, leading to a therapeutic benefit in type 1 diabetes.
Animals ; Apoptosis ; Betacellulin ; Cell Proliferation ; Diabetes Mellitus, Experimental/*surgery ; Glucose Intolerance/*surgery ; Humans ; Insulin-Secreting Cells/*metabolism/physiology ; Intercellular Signaling Peptides and Proteins/genetics/*metabolism ; *Islets of Langerhans Transplantation ; Mice ; Mice, Inbred C57BL ; Rats