ABSTRACT
Objective To construct insulin B chain DNA vaccine and to perform a vaccinating trial for preventing mice from autoimmune diabetes induced by multiple low dose streptozotocin. Methods RT PCR was used to clone insulin B chain, and insulin B chain DNA vaccine was constructed. DNA vaccine was injected into tibilias anterior muscle of C57BL/6 mice in treatment group (T), prophylactic group (P). The morphology of mice islets was investigated by pathology, blood samples were taken to determine glucose and insulin. Group T and group P were compared with group of normal control mice (C) and group of untreated diabetic mice (D). Results (1) Insulin B chain gene was cloned by RT PCR, which ligated with pcDNA3 plasmid. Insulin B chain DNA vaccine was constructed. (2) In group P, after injection of DNA vaccines, 3 (3/10) and 4 (4/10) mice became diabetic in the second week and the third, fourth week respectively, the incidence was significantly less than those of groups D and T. The insulin level showed no difference between group C and the non diabetic mice of group P. The change of pancreas of diabetic mice in group P was similar to group D. Conclusion Insulin B chain DNA vaccine can prevent pre autoimmune diabetes.
ABSTRACT
Objective To investigate the effects of glucagon-like peptide-1(GLP-1)on the expression of apoptosis-related molecules including programmed cell death 5(PDCD-5)gene in pancreatic ? cells induced by proinflammatory cytokines.Methods Mouse islet ?-cell line NIT-1 was incubated for 24 h with cytokine mixture(Mix)in the absence or presence of GLP-1.The apoptotic cells were assayed by flow cytometry after stained with annexin V-FITC and propidium iodide(PI).The expressions of PDCD5,Fas,and caspase 3 were detected using reverse transcription-polymerase chain reaction(RT-PCR)and Western blot.Results The number of both annexin V single positive cells and annexin V/PI double positive cells significantly increased in the cells treated with 30 U/mL interleukin-1?(IL-1?)+ 100 U/mL interferon-?(IFN-?)+ 100 U/mL tumor necrosis factor-?(TNF-?).The expressions of PDCD5,Fas,and caspase 3 at both mRNA and protein levels were upregulated in the cells exposed to the cytokines.The above-mentioned effects of the cytokines were reversed by 10 nmol/L of GLP-1.Conclusion These data show that the proinflammatory cytokines cause pancreatic ? cell apoptosis via activation of PDCD5 signal pathway and that GLP-1 inhibits the upregulation of PDCD5 expression and the subsequent event of apoptosis induced by the cytokines.
ABSTRACT
Objective To study the effect of rosiglitazone on pathologic changes of ? cell ultrastructure in insulin-resistant (IR) rats. Methods IR rat model was established in 6-8-week-old SD rats by high-glucose feeding (70% calories from glucose) for 6 weeks. The IR rats was then divided into IR group (n=10) and rosiglitazone (RSG) group (n=10). Rats in RSG group were treated with RSG 10 ?mol?kg -1?d -1 for 6 weeks by gavage. Ultrastructure of ? cells was observed with transmission electron microscope. Results Systolic blood pressure and serum levels of triglyceride, free fatty acids and insulin in RSG group were lower than those in IR group (all P