Isabelle Sendowski1, Florent Raffin, Anne Braillon-Cros. 1. Pôle "Traumatisme Sonore", Département de Radiobiologie, Centre de Recherches du Service de Santé des Armées (CRSSA), La Tronche Cedex, France. Isendowski@crssa.net
Abstract
CONCLUSIONS: The present findings show that magnesium administration can significantly reduce threshold shift 7 days after gunshot noise exposure. However, this improvement seems to be temporary, suggesting a probable advantage in prolonging the treatment. OBJECTIVE: To evaluate the therapeutic efficacy of magnesium administration after hearing loss induced by gunshot noise. MATERIAL AND METHODS: Forty-eight guinea pigs were exposed to an impulse noise (blank shot from a rifle; 170 or 176 dB SPL peak). The therapeutic efficacy of magnesium was evaluated by administering either the treatment or a placebo to the traumatized animals for 7 days, beginning 1 h after the trauma. Auditory function was explored for up to 14 days of recovery by recording the compound action potential in the round window. The functional study of hearing was supplemented by histological analysis. RESULTS: The threshold shifts of the 170-dB SPL group that received magnesium were significantly lower than those of controls after 2 and 7 days of recovery, but no significant difference was evidenced at 14 days in this group, nor at any time in the 176-dB SPL group. Animals treated with magnesium after the 176-dB SPL exposure had a significant reduction in hair cell loss in the basal region.
CONCLUSIONS: The present findings show that magnesium administration can significantly reduce threshold shift 7 days after gunshot noise exposure. However, this improvement seems to be temporary, suggesting a probable advantage in prolonging the treatment. OBJECTIVE: To evaluate the therapeutic efficacy of magnesium administration after hearing loss induced by gunshot noise. MATERIAL AND METHODS: Forty-eight guinea pigs were exposed to an impulse noise (blank shot from a rifle; 170 or 176 dB SPL peak). The therapeutic efficacy of magnesium was evaluated by administering either the treatment or a placebo to the traumatized animals for 7 days, beginning 1 h after the trauma. Auditory function was explored for up to 14 days of recovery by recording the compound action potential in the round window. The functional study of hearing was supplemented by histological analysis. RESULTS: The threshold shifts of the 170-dB SPL group that received magnesium were significantly lower than those of controls after 2 and 7 days of recovery, but no significant difference was evidenced at 14 days in this group, nor at any time in the 176-dB SPL group. Animals treated with magnesium after the 176-dB SPL exposure had a significant reduction in hair cell loss in the basal region.