The Protective Effect of Orally Ingested Korean Red Ginseng on the Noise Induced Hearing Loss in Mice

It is well known that the saponin of Korean red ginseng (KRG) has an anti-oxidant effect and could suppress the accumulation of lipid peroxidation. The aim of the present study was to observe the inhibitory effect of KRG on mice with noise-induced hearing loss, and to determine its optimal dose. BALB/c mice with a normal hearing level and normal Preyer's reflexes were used in the study. The mice in the permanent-threshold-shift (PTS) group were exposed to noise (120-dB SPL, white noise band) in a noise booth for 3 h a day, for three consecutive days. The mice in the experimental group were given heat-processed red-ginseng extract (50 mg/kg, 100 mg/kg, and 200 mg/kg), and those in the control group were given normal saline alone during their noise exposure. The mice in the temporary-threshold-shift (TTS) group were exposed to noise (120 dBSPL, white noise band) in a noise booth for 3 h. The mice in the experimental group were given heat-processed red-ginseng extract (50 mg/kg, 100 mg/kg, and 200 mg/kg), and those in the control group were given normal saline alone before their noise exposure. The hearing levels of the mice were measured through auditory brainstem response (ABR) immediately and I, 3, 5, 7, and 14 days after their noise exposure. Cochleae were removed from the mice 14 days after their noise exposure. lmmunochemical and immunofluorescent staining were performed to observe the expression of 8-oxoG in cochlea. In the PTS group, the hearing function of the mice in all the groups was not recovered after their noise exposure. In the TTS group, however, the hearing function of the mice in all the groups was recovered within 14 days. Reduced hearing impairment and early recovery were observed in the mice that were given 200 mg/kg KRG, and early recovery was observed in the mice that were given 100 mg/kg KRG The immunopositive staining of 8-oxoG was detected in the stria vascularis in the control group but was diminished in the mice that were given 200 mg/kg KRG The ingestion of more than 100 mg/kg KRG demonstrated a protection and recovery effect on the noiseinduced-TTS group. Since KRG has been reported to be a safe compound even up to hundreds of mg/kg, a higher concentration of it may effectively protect and recover TTS.

마우스에서 고려 홍삼의 구강내 섭취를 통한 소음성 난청의 예방효과

고려 홍삼이 소음성 난청에서 청력 보호 및 회복에 관여하는 지를 밝히기 위하여 마우스에서 홍삼을 투여 후 소음에 노출시켜 청력 역치의 변화 및 와우의 활성 산소 유리기에 대한 노출 정도를 보았다. 영구적 청력 역치 이동의 경우에 홍삼은 청력 보호 및 회복에 관여하지 못했다. 하지만 일과성 청력 역치 이동의 경우에는 홍삼이 어느 정도의 농도 이상으로 투여 된다면 청력 회복에 효과적으로 작용하는 것으로 밝혀졌다. 향후 홍삼의 난청 억제 효과에 대해 적정 농도 및 투여 방법 등에 대한 후속연구가 뒤따라야 하겠고 인간에서 발생하는 소음성 난청에의 적합성 판정을 위해 보다 장깆거인 소음 노출 기간과 장기적인 홍삼 복용에 대한 연구가 필요하겠다. 또한 홍삼내의 여러 활성물질에 관한 연구를 통하여 보다 효과적인 화합물을 찾기 위한 노력도 동반되어야 할 것이다.