Effects of irradiation on hydrodynamic injection-mediated gene expression in mice

Objective: To explore the effects of irradiation on hydrodynamic injection-mediated luciferase reporter gene expression in mice and evaluate the gene transfer efficiency using HGT while applied to murine hematopoietic stem cell transplantation model. Methods: The mice were divided into the irradiated group and the non-irradiated group. The PGL3-luc plasmid expressing luciferase reporter gene was injected into mice by a rapid large-volume injection. Six hours after the injection the luciferase substrate was intraperitoneal injected into mice and the initial level of gene expression was detected through in vivo imaging system. The irradiated group mice received nonmyeloablative doses (700c Gy) of total body irradiation (TBI). The level of gene expression in two groups of mice was then monitored by in vivo imaging system in real time at the 12 th, 24 th, 48 th, 72 nd, 96 th, and 120 th h after the hydrodynamic injection. Results: High expression of the transgene delivered via the tail vein was observed in the mouse liver at the sixth hour after injection and the average expression level of (3739 ± 924.8) RLU/ (sec · mg) protein was obtained. The level of transfer gene expression was similar between mice in the irradiated group and those in the non-irradiated group at various time (P>0.05) but fell to a low level three days after gene transfer. Conclusion: The irradiation after the hydrodynamic injection doesn't affect the level of transfer gene expression in mice. This new type of gene transfer methods can be applied to mouse hematopoietic stem cell transplantation model effectively. (authors)