Post-exposure treatment with ginsenoside compound K ameliorates auditory functional injury associated with noise-induced hearing loss in mice.

Noise-induced hearing loss (NIHL) is thought to primarily involve damage to the sensory hair cells of the cochlea via mechanical and metabolic mechanisms. Unfortunately, initial studies assessing the effectiveness of post-exposure treatment after hearing loss have yielded largely disappointing results. This study explored the effects of oral treatment with Korean red ginseng (RG) and with two bioavailable ginsenoside metabolites, ginsenoside Rh1 and ginsenoside compound K (GCK), in response to NIHL in a murine model. Pharmacological treatments began 24h after noise exposure and were continued once daily for 7 days. Central auditory function was evaluated using auditory middle latency responses, and cochlear function was determined based on transient evoked otoacoustic emissions. Additionally, cochlear hair cell morphology was investigated after noise exposure. Both Korean red ginseng and compound K reduced threshold shifts, central auditory function damage, and cochlear functional and morphological deficits. In contrast, treatment with ginsenoside Rh1 did not result in recovery of NIHL in mice. These results suggest that consumption of Korean red ginseng may facilitate recovery from noise-induced hearing loss. Furthermore, one of the active constituents in ginseng is likely ginsenoside compound K.