Gene therapy for type 1 diabetes mellitus in rats by gastrointestinal administration of chitosan nanoparticles containing human insulin gene.

Aim: To study the expression of human insulin gene in gastrointestinal tracts of diabetic rats.

Methods: pCMV.Ins, an expression plasmid of the human insulin gene, wrapped with chitosan nanoparticles, was transfected to the diabetic rats through lavage and coloclysis, respectively. Fasting blood glucose and plasma insulin levels were measured for 7 d. Reverse transcription polymerase chain reaction (RT-PCR) analysis and Western blot analysis were performed to confirm the expression of human insulin gene.

Results: Compared with the control group, the fasting blood glucose levels in the lavage and coloclysis groups were decreased significantly in 4 d (5.63 +/- 0.48 mmol/L and 5.07 +/- 0.37 mmol/L vs 22.12 +/- 1.31 mmol/L, respectively, P < 0.01), while the plasma insulin levels were much higher (32.26 +/- 1.81 microIU/mL and 32.79 +/- 1.84 microIU/mL vs 14.23 +/- 1.38 microIU/mL, respectively, P < 0.01). The human insulin gene mRNA and human insulin were only detected in the lavage and coloclysis groups.

Conclusion: Human insulin gene wrapped with chitosan nanoparticles can be successfully transfected to rats through gastrointestinal tract, indicating that chitosan is a promising non-viral vector.