Objective: To construct the recombinant adenovirus containing rat insulin-like growth factor 1 (rIGF-1), and then infect to rat islet beta cells-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 infect to RINm5F cells. rIGF-1 protein was detected by Western blot 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 4.0x10(8) pfu/ml. The rIGF-1 was expressed in the RINm5F cells and cell culture supernatants. rIGF-1 expression could inhibit islet cells apoptosis, significantly decrease the level of NO induced by streptozotocin and significantly increase insulin secretion and cells viability.
Conclusion: These results suggested that the high concentration of rIGF-1 in cultured islets may be beneficial in maintaining islet beta cells function and protecting islet beta cells from apoptosis-mediated factors. The apoptosis induced by STZ may be NO-dependent.