AIM: To investigate the efficiency of transfer of A20 gene into pancreas against STZ-induced diabetes. METHODS: PVP-plasmid mixture was directly transferred into the pancreatic parenchyma 2 d before STZ injection. The uptake of plasmid pcDNA3-LacZ or pcDNA3-A20 was detected by PCR and the expression of LacZ was confirmed by histological analysis with X-gal. A20 expression in the pancreas of pcDNA3-A20 transgenic mice was measured by RT-PCR and Western blots. Urine amylase, NO generation, and histological examination were examined. RESULTS: Injection of PVP-plasmid mixture directly into the pancreatic parenchyma increased urine amylase concentration 16 h after operation and reversed it to nearly normal 36 h later. On d 33 LacZ expression could be found in spleen, duodenum, and islets. The development of diabetes was prevented by direct A20 gene transferring into the pancreas and A20-mediated protection was correlated with suppression of NO production. The insulitis was ameliorated in A20-treated mice. CONCLUSION: Injection of PVP-plasmid mixture directly into the pancreatic parenchyma led to target gene expression in islets. Direct transfer of A20 gene into the pancreas protected mice from STZ-induced diabetes. AIM: To investigate the efficiency of transfer of A20 gene into pancreas against STZ-induced diabetes. METHODS: PVP-plasmid mixture was directly transferred into the pancreatic parenchyma 2 d before STZ injection. The uptake of plasmid pcDNA3-LacZ or pcDNA3-A20 was detected by PCR and the expression of LacZ was confirmed by histological analysis with X-gal. A20 expression in the pancreas of pcDNA3-A20 transgenic mice was measured by RT-PCR and Western blots. Urine amylase, NO generation, and histological examination . RESULTS: Injection of PVP-plasmid mixture directly into the pancreatic parenchyma increased urine amylase concentration for 16 h after the operation reversed the normal to 36 h later. On d 33 LacZ expression could be found in spleen, duodenum, and islets. The development of diabetes was prevented by direct A20 gene tr ansferring into the pancreas and A20-mediated protection was correlated with suppression of NO production. The insulitis was ameliorated in A20-treated mice. CONCLUSION: Injection of PVP-plasmid mixture directly into the pancreatic parenchyma led to target gene expression in islets. of A20 gene into the pancreas protected mice from STZ-induced diabetes.