Korean J Otolaryngol-Head Neck Surg.  2007 May;50(5):385-390.

The Effect of IP3 Receptor Inhibition Using 2-APB on Gentamicin Ototoxicity in Cochlear Sensory Cell

• Moon JH
• Jung JY
• Ahn JC
• Seong YS
• Lim ES
• Rhee CK

Abstract

BACKGROUND AND OBJECTIVES: Elevated intracellular calcium level is known to play important roles in the apoptotic pathway. IP3 receptor (ligand-gated channels that release Ca2+ from intracellular stores) is emerging as a key site for regulation of apoptosis. 2-Aminoethoxydiphenyl borate (2-APB) is one of the reliable IP3 receptor antagonists. We examined the effect of 2-APB on gentamicin ototoxicity in vitro, using the HEI-OC1 cell line. MATERIALS AND METHOD: HEI-OC1 cells were trWWeated with 100micrometer gentamicin. Using a CaspACE assay, we measured the caspases-3 activity in the gentamicin treated hair cells with and without 2-APB pre-incubation. We also observed intra-cellular calcium concentrations in HEI-OC1 cells using a confocal microscopy (calcium green-1 stain). Live cell imaging was performed by using fluorescence video-time lapse system.
RESULTS
Cytosolic calcium elevation by gentamicin was remarkably inhibited by 2-APB. Caspases-3 activities of gentamicin treated cells were higher than those of the control. After incubation with 2-APB, caspases-3 activities and cell death of gentamicin treated cells were shown to decrease.
CONCLUSION
2-APB reduces Caspases-3 activity in the gentamicin treated HEI-OC1 cells by inhibition of cytosolic calcium increase.

Keyword

2-APB; Caspase-3; Gentamicin; Calcium; IP3 receptor

MeSH Terms

Apoptosis
Calcium
Caspase 3
Cell Death
Cell Line
Cytosol
Fluorescence
Gentamicins*
Hair
Inositol 1,4,5-Trisphosphate Receptors*
Microscopy, Confocal
Calcium
Caspase 3
Gentamicins
Inositol 1,4,5-Trisphosphate Receptors