Histopathological studies on a chemical injury of the tongue. Healing process of damaged tongue by acid or alkali at low concentration

Tongue injuries are caused mechanically, thermically, chemically and radiologically, etc., but these lesions and healing processes seem to have been less studied.The authors examined tongue injuries by acid or alkali substances, and discussed some problems about the healing process.Experimental methods:Six-week-old Wistar strain male rats were used as experimental animals. HC1 was used as acid, while NaOH used as alkali. The concentration of each chemical used in this study was 10, 20 and 30% diluted aqueous solution with application time of 1 minute. These experimental animals were generally anesthesized with Nembutal and the afilter paper sufficiently soaked with HCl or NaOH was applied to the anterior 2/3 part of tongue dorsal surfae.Thirty day-research was made on tongue damage and recovery which were examined by light and scanning electron microscope.Experimental results:Macroscopically, no remarkable change occurred by HCl or NaOH, but light and scanning electron microscopic examinations revealed the tongue injured by increased drug concentration and considerably destroyed taste buds of fungiform papillae. One or two weeks after the tongue injury, these damaged areas showed healing of the filiform and fungiform papillary wounds, and 30 days after the injury they showed regeneration with an almost normal structure of the taste bud. In this case, however, though usually a fungiform papillary taste bud has a taste pore, some of the regenerated taste buds had several taste pores, a very intresting finding in terms of the regeneration mechanism.