Adenovirus-mediated Insulin-like Growth Factor 1 Gene Of Streptozotocin Induced Pancreatic �� Cell Damage Protective Effect

Objective To construct the recombinant adenovirus containing rat insulin-like growth factor 1(rIGF-1), and then infect to rat isletβcells—RINm5F cells with the virus to investigate the role of rIGF-1 to streptozotocin-induced cell impairment in vitro.Methods Recombinant adenovirus encoding rIGF-1 was constructed, and then infected to RINm5F cells. rIGF-1 protein was detected by Western blotting analysis and ELISA method. Then streptozotocin was used to induce RINm5F cells impairment. The levels of nitric oxide were detected in cells culture supernatants. The cells function was evaluated by glucose-stimulated insulin production. The apoptosis was analyzed by flow cytometry. Thiaoollyl blue viability assay was applied to exam the number of viable cells.Results The recombined adenovirus-rIGF-1 was constructed successfully and its titer was about 1.0×109pfu/ml. The titer of Ad-eGFP was about 8.0×108pfu/ml. The rIGF-1 was expressed in the RINm5F cells and cells culture supernatants. rIGF-1 can inhibit islet cell apoptosis and significantly decrease the level of NO induced by streptozotocin. Also it can significantly increase insulin secretion and cells viability.Conclusion These results suggested that locally produced IGF-1 from cultured islets may be beneficial in maintainingβcells function, protecting islet cells from apoptosis-mediated factors and promoting islet survival, which showed the potential therapy for type 1 diabetes mellitus. The apoptosis induced by STZ maybe NO-dependent. Objective To investigate the protective role of adenovirus vector mediated insulin-like growth factor 1 (IGF-1) on streptozotocin-induced type 1 diabetic mellitus (T1DM) of SD rats, and observe the difference among different ways of injection.Methods Ninety male SD rats aged from four to six weeks were randomly divided into six groups. Group A is diabetes mellitus control goup; Group B is vacuity group without special disposal; Group C received the intraperitoneal injection of adenovirus vector mediated empty green fluorescence protein (8.0×107pfu); Group D, E, F received injection of adenovirus vector mediated IGF-1 gene (1.0×10 pfu) separatedly by intramuscular injection, intraperitoneal injection and pancreas tegument injection. Later, Group A and D, E, F received intraperitoneal injection of stz 50mg/kg in order to induce diabetic mellitus. Weight and blood glucose were measured. Five weeks later, all rats were executed, the incidence of diabetic mellitus and the degree of pancrea inflammatory infiltration were observed, and the expression of IGF-1 was detected by the immunohistochemical and enzyme linked immunosorbent assay techniques.Results The incidence of T1DM of each group was that group A100%, group D 61.5%, group E 60% and group F 66.7%. Compared with control groups, experimental groups had a lower incidence of diabetes and a lower degree of average blood glucose; pancrea pathology showed that inflammatory infiltration was lighter; IGF-1 had a higher expression in islet cell; a higher degree of insulin in serum in experimental groups. But there was no difference of IGF-1 in serum in all groups.Conclusion Adenovirus vector mediated IGF-1 can protect STZ-induced T1DM of SD rat from diabetes in some degree, and it has no relationship with the ways of injection.