OBJECTIVETo study the feasibility and the characteristics of recombinant baculovirus as spiral ganglion cells (SGC) gene transfer vector.

METHODSAfter the generation of baculovirus- green fluorescent protein( Bac-GFP) according to Bac-to-Bac baculovirus expression system, SGC were infected by Bac-GFP with different multiplicities of infection (MOI) and different concentrations of sodium butyrate. The transfection cell rate and mean fluorescence strength (MFS) were detected by fluorescence microscopy and flow cytometry. Toxicity effects of recombinant baculovirus vectors and sodium butyrate on SGC were determined by spectroscopic measurement of 3-(4, 5)-dimethylthiahiazo (-z-y1)-3, 5-diphenytetrazoliumromide (MTF).

RESULTSBaculovirus was able to infect primary SGC cultures. The dose-response characteristics of Bac-GFP were determined on SGC, and the expression level could be up-regulated by sodium butyrate. Infection with Bac-GFP in the absence or presence of sodium butyrate (< or =10 mmol/L) was considered to be non-cytotoxic to primary SGC. GFP had been expressed in SGC at 6 h post-infection and the highest numbers of cells expressing GFP were observed at approximately 48 h post-infection.

CONCLUSIONSBaculovirus is a novel and promising tool for gene transferring into the cochlear nervous system both for studies of the function of foreign genes and the development of gene therapy strategies.