RESUMO
PURPOSE: We delivered interleukin-4 (IL-4) plasmid (pCAGGS-IL-4) using the biodegradable polymer, poly[alpha-(4-aminobutyl)-L-glycolic acid] (PAGA), to prevent autoimmune insulitis in NOD mice. METHODS: The pCAGGS-IL-4/PAGA complex was transfected to 293T cells. The expression level of IL-4 was measured by ELISA. The pCAGGS IL-4/PAGA complex was injected once to NOD mice intravenously at the age of 4 weeks. RT-PCR was performed to evaluate the level of the IL-4 mRNA in the liver. At 6 weeks after the injection, the grade of insulitis of the mice was evaluated by double blind methods. RESULTS: In vitro transfecton assays showed that PAGA enhanced the expression of IL-4 in 293T cells. RT-PCR of the liver showed that IL-4 was expressed highest in the complex injected group. In the plasmid/PAGA complex injected group, the prevalence of severe insulitis in NOD mice was markedly improved, suggesting that PAGA enhanced the delivery of IL-4 plasmid. CONCLUSION: The pCAGGS-IL-4/PAGA complex is an effective system to prevent autoimmune insulitis in NOD mice and applicable for the prevention of autoimmune diabetes.