Quantification of muscle damage over time. The gastrocnemius muscle was injected with 50 μL (1 μg / μL) of pAdapt Empty followed by a 200 V/cm electric pulse delivery (black bars), 50 μL of PBS and 200 v/cm electroporation (striped bars), electroporation alone (white bars), 50 μL pAdapt Empty (red bars), 50 μL of PBS (blue bars), or were not treated (grey bars). The muscle and blood were collected 2, 7, and 14 days after treatment. Four animals per group. Data are expressed as means ± SD. A: Creatine kinase plasma levels. B: percentage of necrotic fibers determined in the electroporated part of the muscle. Statistical analysis (Scheffe's test) showed a significant difference of the muscle damage at day 2, 7 and 14 between the mice treated by electroporation without pre-injection and those pre-injected with PBS or plasmid and then treated with electroporation. There is not a significantly different damage between the muscle pre injected with PBS and the muscle pre injected with plasmid prior to the electroporation. The p values between the pre injected groups (with PBS or with plasmid) and the "electroporation only" group are indicated above the bars.