[Adenovirus-mediated delivery of bcl-2 gene attenuates cisplatin-induced degeneration of cultured spiral ganglion cells.].

Objective: To assess the protection against cisplatin-induced ototoxicity by adenovirus-mediated overexpression of the bcl-2 gene in cultured spiral ganglion cells (SGC).

Methods: SGC from P3 rats were cultured in vitro and exposed to adenovirus vector carrying green fluorescent protein gene (Ad-GFP), followed by immunocytochemical analysis for expression of the neuron-specific marker Neurofilament 200 (NF200) and detection under laser scanning confocal fluorescence microscope. Then, SGC were transduced by Ad-bcl-2 and the expression of human bcl-2 protein was evaluated by Western Blot. Finally, the cultures of SGC were divided into 4 groups: the group of Ad-bcl-2 transfection followed by cisplatin treatment, the group of Ad-GFP transfection followed by cisplatin treatment, the group of cisplatin treatment only and the untreated group. Cisplatin worked for 48 hours at a concentration of 2 microg/ml. Outcome measures included survival number of SGC and longest neurite length by using ImageJ software.

Results: SGC were cultured successfully in vitro and transfected by adenovirus vector safely and efficiently. By Western Blot, human bcl-2 protein was expressed in the group after exposure to Ad-bcl-2, but not in the Ad-GFP transfected SGC. Cisplatin exposure resulted in shrinking of neuritis and pyknosis of cell body, even cell death. Expression of bcl-2 in the SGC provided a significant level of protection against cisplatin-induced SGC degeneration.

Conclusions: Our results suggest that SGC can be transduced by adenovirus vector safely and efficiently in vitro. Adenovirus-mediated delivery of the bcl-2 gene attenuates cisplatin-induced SGC degeneration.