PURPOSE: Recombinant adeno-associated viruses (AAV) are widely used vectors for gene transfer into the central nervous system (CNS).However, Low transduction efficiency andthe delay in transgene expression have hampered it from wide application in such as early embryonic development and the brain of higher mammals for both basic and clinic researches. This study is designed to establish a new means to improve both the efficiency and timing of AAV transduction in transgene expression.  
METHODS: By co-administration of doxorubicin with AAV8 vector into the cortex of cat, we firstly evaluated the effect of doxorubicin on enhancing vector transfection and transgene expression at different time points after infection. Then, we characterized the dose dependence of doxorubicin on AAV-mediated gene expression by varying the concentration of doxorubicin. The toxicity of doxorubicin was also examined by cell apoptosis assay.   
RESULTS:Local administration of 10 μg/mL doxorubicin remarkably facilitated AAV8-based gene transfer to neurons, increasing both cell numbers and expression level of GFP. The doxorubicin accelerated GFP expression is observed to appear as earlier as the third day after infection, and increased GFP intensity is persistent through the following multiple weeks in time. Doxorubicin was found to increase the neural expression of GFP at doses between 0.1 ~ 10 μg/mL with little toxicity, but induced neuron loss at a dose higher than 30 μg/mL.
CONCLUSIONS:Co-infusion of doxorubicin accelerates AAV-based transgene expression in the cortex of higher mammals. This improved efficiency and timing of AAV transduction might have great potentials in the application for early embryonic development and other neurophysiological research for CNS diseases in higher mammals.