The reverse block copolymer Pluronic 25R2 promotes DNA transfection of skeletal muscle.

Muscle is an important and attractive target for gene therapy. Recent findings have shown that neutral amphiphilic triblock copolymers with a PEO-PPO-PEO arrangement significantly increase muscle transfection as compared to naked DNA. We were interested in evaluating whether reverse Pluronics (PPO-PEO-PPO) also possess transfection properties. Therefore, we measured the in vitro and in vivo transfection activity of 25R2 and 25R4, two copolymers that differ by their hydrophilic/hydrophobic balance. The results show that 25R2 significantly increases the transfection level in muscle compared to naked DNA. Taken together, this work demonstrates that the reverse Pluronic 25R2 possesses interesting properties for in vivo transfection.