epidermal-growth-factor and Blast-Injuries

To study the expression of epidermal growth factor receptor (EGFR) on cochlear hair cells of normal and explosion-stricken guinea pigs and the effects of epidermal growth factor (EGF) and dexamethasone (DXM) treatment for blast hearing loss.. Immunohistochemical technique and auditory brainstem response (ABR) test were used.. Scattered expression of EGFR was seen in inner hair cells (IHCs) and outer hair cells (OHCs) in normal guinea pigs. Segmentally distributing positive reaction was also located in stereocilia of hair cells. Distribution of EGFR reaction was seen in the cytoplasm of IHC 24 hours after exposure to blasts, and in the stereocilia of IHC and the cuticular plate of OHC 72 hours postexposure. At one week EGFR reaction in hair cells increased obviously and part of OHC stereocilia also showed positive reaction. EGFR reaction reduced at two weeks, though positive reaction could still be found in the stereocilia of hair cells at one month. Combination of EGF and DXM administrations promoted hearing recovery significantly.. The healing of injured hair cells may be related to EGF.

Topics: Animals; Blast Injuries; Deafness; Dexamethasone; Epidermal Growth Factor; ErbB Receptors; Explosions; Guinea Pigs; Hair Cells, Auditory; Random Allocation

The expression of epidermal growth factor receptor (EGFR) in cochlear hear cells was studied in normal and guinea pigs exposed to blasts. The effects of epidermal growth factor (EGF) and dexamethasone (DXM) treatment for blast hearing loss and the underlying mechanisms were also explored. Scattered expression of EGFR was seen in IHCs and OHCs in normal guinea pigs. Segmentally distributing positive reaction was also located in stereocillia of hair cells. Distribution of EGFR reaction was seen in the cytoplasm of IHC 24 hours after exposure to blasts, and in the stereocillia of IHC and the cuticular plate of OHC 72 hours postexposure. At one week EGFR reaction in hair cells increased obviously and part of OHC stereocillia also showed positive reaction. EGFR reaction reduced at two weeks, though positive reaction could still be found in the stereocillia of hair cells at one month. Combination of EGF and DXM administrations promoted hearing recovery significantly. Our results suggest that healing of injured hair cells may be to EGF.

Topics: Animals; Anti-Inflammatory Agents; Blast Injuries; Dexamethasone; Epidermal Growth Factor; ErbB Receptors; Evoked Potentials, Auditory, Brain Stem; Female; Guinea Pigs; Hair Cells, Auditory; Hearing Loss, Noise-Induced; Male