The use of non-viral carrier

polyethyleneimine-g-methoxypoly(ethylene glycol) (PEI-g-MPEG) for interleukin-10 (IL-10) gene delivery into rat dorsal root ganglion cells (DRGs) was examined in vitro.Electrophoresis

ethidium bromide exclusion

SEM

size and zeta () potential measurements were performed to characterize the nanocomplex

PEI-g-MPEG/pDNA.In addition

the cytotoxicity

transfection efficiency and IL-10 protein expression level in comparison with lipofectamine as a delivery agent were determined.Results showed that plasmid DNA was completely complexed by PEI-g-MPEG at a nitrogen-to-phosphor (N/P) ratio of 5.The PEI-g-MPEG/pDNA complexes were well-distributed and spherical with smooth surface.As the proportion of PEI-g-MPEG increased

i.e.when N/P ratio increased from 1 to 30

the size of the PEI-g-MPEG/DNA complexes decreased from 229 nm to 130 nm

while the surface charge increased from -19 mV to 32 mV

which led to the increased cytotoxicity.Flow cytometry revealed that the highest transfection efficiency (24%) using PEI-g-MPEG as a delivery agent was obtained at N/P charge ratio of 15

which was higher than that of lipofectamine (17%) at the same N/P value.After transfection

rat IL-10 expression in DRGs primary culture assessed using ELISA was observed to localize in the cytoplasm at 48 h in concordance with the result obtained for EGFP expression.These results indicated that PEI-g-MPEG could be a potential candidate for gene delivery during the therapy of neuropathic pain.