Regeneration of Hair Cell Epithelia in the Chick and Salamander

The acousticolateralis sensory system is characterized by a specific receptor cell type called the sensory hair cell and is found in all vertebrates. There are two types of hair cell sensory epithelia based on location: those of the inner ear, such as the organs for hearing and balance, and the lateral line system located within the epidermis. In mammals, including humans, loss or damage of the hair cells of the auditorysystem results in permanent hearing loss. However, this is not the case with birds and amphibians. Amphibians, with a lateral line system, are capable of replacing lost or damaged hair cells or hair cell epithelia, called neuromasts. This researcher is concerned with identifying the molecular clues used by the axolotl salamander to regulate this regeneration. Alcian blue staining was used to compare the extracellular matrix of normal and regenerating neruomasts. Alcian blue staining at two different pHs can distinguish between highly sulfated and non-sulfated forms of glycosaminoglycans and proteoglycans. No differences could be found between control and regenerating hair cell epithelia. These results indicate that the level of sulfation is not involved in hair cell regeneration in the axolotl; however, it does not rule out a role for the extracellular matrix in this process, but rather suggests that more specific probes are needed for further investigation