Improved morphological techniques for screening potentially ototoxic compounds in laboratory animals

A technique is described for morphological examination of the organ of Corti which can be used in routine toxicological studies. This involves the dissection of a critical point-dried cochlea and examination of a surface preparation of the entire organ by scanning electron microscopy. The procedure is simple and far less time consuming than that previously used for light microscopy. Quantitative estimates of damage induced in the organ of Corti either by the administration of ototoxic compounds or as a response to noise-induced or age-related changes can be obtained. Details are given for the application of this technique to two species commonly used in toxicity studies. With minor modifications it could be applied to many other species of animal.