Noise Induced Expression of 72kD Heat Shock Protein in Rat Saccule / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: Heat shock protein (HSP) is an intracellular protein, expressed for cell protection under stressful condition. Expression of HSP was found in cochlear after noise stimulation. The vestibular end organs, especially saccule, have been known to be damaged by loud sound because of its anatomical and embryological vicinity with the cochlea. In this study, we observed the function of HSP72 that it is indeed expressed in rat saccule following noise stimulation. MATERIALS AND METHODS: Experimental animals were exposed to noisy environment at 100, 110 and 120 dB SPL for 90 minutes. Noise stimulation was transferred through a tone hook of behind-the-ear type hearing aid. Saccule was dissected and stained immunohistochemically and examined for expression of HSP under light microscope. RESULTS: Strong immunoreactivities were observed at type I and II hair cells of rat saccule which received noise of 120 dB for 90 minutes. Stronger imm-unoreactivities were found along the marginal areas of the saccule. CONCLUSION: These findings suggest that HSP72 are expressed in rat saccule following overthreshold noise and it could be presumed that HSP72 may have a protective role against noise trauma.