(−)-Epigallocatechin-3-gallate protects cultured spiral ganglion cells from H₂O₂-induced oxidizing damage

Abstract

Objective Oxidants play an important role in many diseases, including hearing loss. We hypothesized that (−)-epigallocatechin-3-gallate (EGCG) would protect spiral ganglion cells (SGCs) from H₂O₂-induced oxidizing damage.

Material and Methods SGCs of postnatal day 1–3 mice were cultured in vitro. H₂O₂ and EGCG were used at various concentrations. The apoptotic rate of SGCs was evaluated using Hoechst 33 258 staining, and cell viability was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide method. Semi-quantitative reverse transcriptase polymerase chain reaction was used to observe manganese superoxide dismutase (MnSOD) gene expression of SGCs treated with H₂O₂ and EGCG.

Results The viability of cultured SGCs was significantly decreased, and the apoptotic rate of SGCs significantly increased, at H₂O₂ concentrations ≥50 μM compared with the control (p<0.05). MnSOD gene expression was upregulated with increasing H₂O₂ concentration in cultured SGCs, while this upregulation was suppressed by EGCG.

Conclusion It is suggested that EGCG, as an antioxidant, significantly protects auditory neurons against H₂O₂-induced oxidative damage.

Keywords:

• antioxidant enzyme
• apoptosis
• cell viability
• (−)-epigallocatechin-3-gallate
• H2O2
• manganese superoxide dismutase gene
• oxygen free radical
• semi-quantitative reverse transcriptase polymerase chain reaction
• spiral ganglion cells

Xie DH, Liu GH, Zhu GH, Wu WT, Ge SL. (−)-Epigallocatechin-3-gallate protects cultured spiral ganglion cells from H₂O₂-induced oxidizing damage. Acta Otolaryngol 2004; 124: 464–470.

Xie DH, Liu GH, Zhu GH, Wu WT, Ge SL. (−)-Epigallocatechin-3-gallate protects cultured spiral ganglion cells from H₂O₂-induced oxidizing damage. Acta Otolaryngol 2004; 124: 464–470.