The synergetic effect of γ-irradiation and noise on damage of cochlear

Under the action of noise exposure (105±2 dBA,duration of 30 min),γ-irradiation (single irradiation of 80 Gy) and combined exposure of them (γ-irradiation followed by noise),the hearing loss and pathological change of hair cells of the cochlea in guinea pigs are respectively measured and examined by means of chronic induction of ecochg via canalis facialis and scanning electron microscope in this study.The results show that the hearing loss for combined exposure group exceeded the summation loss caused by irradiation and noise alone,and the damage of outer hair cells in organ of Corti was severer than that of irradiation or noise exposed group.It indicates that the synergetic effect of γ-irradiation and noise exposure occurs on cochlear damage in guinea pigs.In the combined exposure the curve shape of threshold shifts is similar to γ-irradiation alone,but the amount of threshold shifts,is considerably more than that of γ-irradiation.It shows that the damage property of the cochlear may mainly depend on the γ-irradiation,and the noise exposure is only an accelerating agent for the synergetic effects on the damage of the cochlear.