Protective Effects of Pentoxifylline and Nimodipine on Acoustic Trauma in Guinea Pig Cochlea

Abstract

To examine the protective effects of the vasodilator and hemorheologically active drug pentoxifylline and the calcium channel blocker nimodipine on the cochlea after acoustic overexposure in guinea pigs. Eighteen guinea pigs were used. The animals were divided into 5 groups: 1) control, 2) acoustic trauma, 3) nimodipine plus acoustic trauma, 4) pentoxifylline plus acoustic trauma, and 5) pentoxifylline plus nimodipine plus acoustic trauma. Nimodipine was given to the guinea pigs 3 mg/kg intraperitoneally in a single dose; pentoxifylline was given 150 mg/kg in a single dose intraperitoneally. A gunnery range was used to create acoustic trauma. The auditory brainstem response of each guinea pig was determined first; then, the animals were killed, and their cochleas were examined under an electron microscope. In the acoustic trauma group, negative auditory brainstem response potentials were seen as was well-adjusted cellular damage to the organ of Corti. In the pentoxifylline group, near-normal auditory brainstem response recordings and organ of Corti histologic findings were found. Organ of Corti damage was seen in the pentoxifylline plus nimodipine plus acoustic trauma group. We determined that pentoxifylline was highly protective against noise, but nimodipine was not. Also, pentoxifylline and nimodipine, when used together, increased damage to the organ of Corti.