Abstract
An efficient gene carrier to the brain is required for successful gene therapy of ischemic stroke. In this study, deoxycholic acid-conjugated polyethylenimine (DA-PEI) was synthesized and evaluated as a heme oxygenase-1 (HO-1) gene carrier for ischemic stroke gene therapy. Gel retardation assay and heparin competition assay showed that DA-PEI formed a stable complex with plasmid DNA. In vitro transfection assays with the luciferase gene showed that DA-PEI had higher transfection efficiency than polyethylenimine (25 kDa, PEI25k) and lipofectamine in Neuro2A cells. Furthermore, DA-PEI had less toxicity than lipofectamine. To evaluate the therapeutic effects of the pβ-HO-1/DA-PEI complex, the complex was injected locally in the brain of the transient middle cerebral artery occlusion animal model. In in vivo studies, DA-PEI was more effective than PEI25k in delivering pβ-HO-1 to the ischemic brain and achieved higher HO-1 expression. As a result, the pβ-HO-1/DA-PEI complexes more effectively reduced infarct volume and the number of apoptotic cells compared with the pβ-HO-1/PEI25k complex. The results suggest that DA-PEI will be useful for HO-1 gene therapy of ischemic stroke.