Astragalus membranaceus improves endothelial-dependent vasodilator function in obese rats / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of Astragalus membranaceus (AM) on endothelial-dependent (EDV) and non- dependent (EIV) vascular relaxation in ex vivo thoracic aortic rings of obese rats.</p><p><b>METHODS</b>Fifteen SD rats were randomized into 3 equal groups, namely the control group fed with normal chow, obese group with high-fat chow, and AM intervention group fed with high-fat chow and daily AM gavage. The rats were sacrificed after 6 weeks of feeding, and the aortic rings were dissected and cut into 3-mm rings. The response to acethylcholine (Ach) and sodium nitroprusside (SNP) were examined in organ bath. In ex vivo study, the aortic rings obtained from the control group and obese group were incubated with AM or vehicle for 3 h in organ bath before testing the EDV and EIV. The body weight and weight of the visceral fat in each group were recorded.</p><p><b>RESULTS</b>The weight of visceral fat was greater in the obese group than in the control group, and a 6-week AM treatment significantly reduced the fat tissue due to high-fat diet. The maximum EDV value was (87.0 - or + 3.5)% in the control group, (54.8 - or + 7.8)% in the obese group, and (69.8 - or + 5.7)% in AM intervention group; the EIV values were comparable between the 3 groups. After incubation with AM, the maximum EDV values of aortic rings obtained from the obese group were significantly increased from (55.6 - or + 8.3)% to (85.1 - or + 4.5)%.</p><p><b>CONCLUSION</b>AM can improve endothelial dysfunction in obese rats, and the mechanism involves improved insulin resistance and increased endothelium-derived NO productor function.</p>

Role of apoptosis and mitochondrial apoptotic pathway in glucolipotoxicity-induced islet beta-cell dysfunction / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the mechanism of beta-cell dysfunction induced by glucolipotoxicity in high fat-fed obese rats.</p><p><b>METHODS</b>Eighteen high-fat obese male Wistar rats were assigned into 3 groups and underwent 48-hour infusion through the jugular vein with normal saline (n=6), 20% intralipid + heparin (FFA group, n=6), or 25%glucose +20% intralipid + heparin (GS-FFA group, n=6). The plasma beta-hydroxybutyric acid (beta-HBA) was measured before and at the end of the infusion. After the infusion, the rats were sacrificed following an intravenous glucose tolerance test (IVGTT) to remove the tail of the pancreas for detection of apoptotic islet cells using TUNEL method. Immunohistochemical staining was performed to detect the expression of cytochrome c (cyt c), apoptosis-inducing factor (AIF), caspase-9 and caspase-3 in the islet cells.</p><p><b>RESULTS</b>At the end of the infusion, all the rats exhibited increased plasma beta-HBA levels, which was the highest in the GS-FFA group (P<0.05). IVGTT performed after the infusion showed a significantly lower insulinogenic index in GS-FFA group than that in NS and FFA groups. Greater number of apoptotic islet cells was found in the GS-FFA group than in the FFA and NS groups (P<0.05), and the islets had significantly higher levels of cyt c, AIF, caspase-9 and caspase-3 in the former group than in the latter two groups (P<0.05).</p><p><b>CONCLUSIONS</b>Hyperglycemia and high free fatty acid level synergistically impair insulin secretions to cause ketone overproduction in high fat-fed obese rats. The beta-cell dysfunction due to glucolipotoxicity is associated with increased beta-cell apoptosis and activation of mitochondrial apoptotic pathway.</p>

Construction and expression of a prokaryotic vector of recombinant human adiponectin global domain / 南方医科大学学报

<p><b>OBJECTIVE</b>To construct and express the recombinant human adiponectin (gAd) global domain.</p><p><b>METHODS</b>gAd complementary DNA (cDNA) was obtained from human fat tissue by RT-PCR. The PCR product was cloned into the vector pMD18-T and the prokaryotic expression vector pET32a(+). The recombinant vector was identified by digestion with double restriction endonucleases SalI and EcoRI, PCR and sequence analysis. The recombinant plasmid containing gAd gene was transformed into E. coli BL21 (DE3), and the expression of the fusion protein His-gAd was induced by IPTG.</p><p><b>RESULTS</b>The gAd cDNA of 412 bp was obtained from the total RNA of the fat tissue and verified by sequence analysis.</p><p><b>CONCLUSION</b>The recombinant plasmid could stably express the 34-kD fusion protein His-gAd in the engineered bacteria in the form of inclusion bodies.</p>

The associations of HLA-DQB1 gene with onset age and autoantibodies in type 1 diabetes / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To evaluate the associations of human leukocyte antigen (HLA) DQB1 gene with onset age and autoantibodies in type 1 diabetes mellitus(T1DM) in Chinese Han population in Sichuan area.</p><p><b>METHODS</b>Forty-six type 1 diabetic patients and 52 healthy control subjects were involved in this study. HLA-DQB1 typing was performed by polymerase chain reaction-sequence specific primer(PCR-SSP). Glutamic acid decarboxylase antibody (GADA) and islet cell antibody (ICA) were qualitatively analyzed by enzyme linked immunosorbent assay (ELISA).</p><p><b>RESULTS</b>The positive rate of DQB1*0201 was higher in T1DM than in controls (OR=18, P<0.005), but those of DQB1*0601, *0602 were higher in controls than in T1DM(OR=0.07, 0.31 respectively, both P<0.05).The positive rate of DQB1*0602 in type 1 diabetic patients with onset age>or=20 years was higher than that in the patients with onset age <20 years (P<0.05). GADA was more frequent in DQB1*0201(+) patients than in DQB1*0201 (-) patients (P<0.025).</p><p><b>CONCLUSION</b>The findings show that DQB1*0201 is susceptible to T1DM, whereas DQB1*0601, *0602 are protective in Chinese Han population in Sichuan area. DQB1*0602 may delay the onset of T1DM. The positive rate of DQB1*0201 correlates positively with that of GADA.</p>

Molecular scanning of candidate mtDNA gene fragment in diabetic pedigrees / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore novel pathogenic mutation in the mitochondrial DNA gene in diabetic pedigree.</p><p><b>METHODS</b>Twenty-eight suspected mitochondrial DNA diabetic families were recruited. The gene fragment was produced by PCR, and mutation was detected by direct sequencing.</p><p><b>RESULTS</b>In one pedigree, the proband and her mother were found carrying the most common nt3243 A --> G mutation and another 16S rRNA 3205C --> T mutation. But only 3205C --> T was found in her affected brother. All the two patients were deaf and developed diabetes in early age, characterized by impaired beta cell function and low body mass index (BMI). The proband had relatively higher lactic acid concentration than normal individuals. A novel ND1 gene 3434 A --> G(TAT --> TGT) mutation was explored in another proband with deafness and her affected family members.</p><p><b>CONCLUSION</b>16SrRNA 3205C --> T mutation was found in a mitochondrial diabetes mellitus pedigree, implying its potential pathogenic role in diabetes. Another novel ND1 3434 A --> G mutation was found in another diabetic pedigree. Because this mutation causes amino acid change (Tyr --> Cys) and is co-segregated with diabetes, it may be diabetogenic.</p>

Establishment of perfusion technique for isolated rat pancreas / 中华内分泌代谢杂志

Objective To establish an isolated rat pancreas perfusion technique,a method for the precise measurement of insulin secretion in vitro.Methods An isolated rat pancreas perfusion technique was applied in the study of insulin secretion from?-cells in 10 high-fat diet-induced obese Wistar rats.Results For the assessment of the functional integrity of the perfused pancreas,the isolated pancreas of 6 rats met all the criteria: (1)The constancy of perfusion pressure was kept over the whole experiment time[(70?5)mm Hg,1 mm Hg= 0.133 kPa].(2)The duodenal peristaltic activity of isolated pancreas and duodenum block was present after perfusion experiment.(3)Total insulin response to arginine stimulation was significantly increased as compared with glucose stimulation[maximum insulin secretion rate:(987?100)?U/min vs(545?50)?U/min,P