Expression patterns of non-viral transfection with GFP in the organ of Corti in vitro and in vivo

Background Diseases of the inner ear such as presbycusis, tinnitus, sudden hearing loss, and vertigo affect many patients, but so far there are no specific therapy options. Gene therapy might become a potential modality of treatment. Viral vectors are standard in animal models to date. Future considerations, however, call for a further evaluation of non-viral transfection methods. Materia and methods. The non-viral transfection agents Metafectene (TM), Superfect (TM), Effectene (TM), and Mirus TransIT (TM) were incubated with a plasmid coding for GFP. In vivo, the plasmid-agent mix was injected via the membrane of the round window, and 48 h later the inner ear was perfused, harvested, decalcified, and histologically evaluated for GFP expression. Results. Cationic lipids (Metafectene (TM)) and dendrimers (Superfect (TM)) were able to transfect cells in the area of the organ of Corti and lead to GFP expression. The polyamine (Mirus TransIT (TM)) did show expression of GFP in the area of Rosenthal's canal and in the area of the inner hair cell. The combination of a non-liposomal lipid with a DNA condensing component (Effectene (TM)) did not show transfection of the organ of Corti. In the area of the spiral ganglia cells, GFP expression was seen with all the transfection agents. Conclusions.Non-viral transfection agents are able to introduce a reporter gene in cells of the inner ear in vitro and in vivo. There are, however, differences in the efficiency of the transfection. They might be an alternative in gene therapy of the inner ear. Further investigations to elucidate their potential are needed.