Zinc protection against pneumolysin toxicity on rat cochlear hair cells.
Audiol Neurotol. 2007-09-21; 13(1): 65-70
DOI: 10.1159/000108763
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1. Audiol Neurootol. 2008;13(1):65-70. Epub 2007 Sep 21.
Zinc protection against pneumolysin toxicity on rat cochlear hair cells.
Franco-Vidal V(1), Beurg M, Darrouzet V, Bébéar JP, Skinner LJ, Dulon D.
Author information:
(1)Otolaryngology and Skull Base Surgery Department, University of Bordeaux 2
Victor Segalen, Bordeaux, France.
Streptococcus pneumoniae can induce local and systemic diseases such as
meningitis, otitis media, and pneumonia. One third of these meningitis cases can
be associated with irreversible sensorineural hearing loss whose mechanisms
likely involves the exotoxin pneumolysin (PLY) that irreversibly damages cochlear
hair cells (HCs). In the respiratory system and in neuron it has been
demonstrated that zinc deficiency increases severity and mortality of such
infections in animal models and in children. Moreover, zinc supplementation can
decrease the severity of pneumococcal respiratory infections. The aim of our
study was to assess the potential protective effect of zinc against PLY toxicity
on HCs in culture. Our results showed that in the presence of zinc at
concentration as low as 1 microM, the toxicity of PLY was largely reduced by
about 50% for both inner and outer HCs. At 300 microM of zinc, protection
significantly increased with 62 and 55.2% for IHCs and OHCs, respectively. Our
results suggest that the protective effect of zinc is likely due to an inhibition
of the toxin incorporation and aggregation into the plasma membrane, thus
preventing calcium influx through the toxin pores. Our findings raise the
possibility that treatments with zinc may help to prevent debilitating otological
sequelae from pneumococcal infection.
(c) 2008 S. Karger AG, Basel.
DOI: 10.1159/000108763
PMID: 17890859 [Indexed for MEDLINE]