Preventive and therapeutic effects of low level laser irradiation on gentamicin vestibulotoxicity in rat utricle

摘要

Purpose: To investigate the effects of low level laser (LLL) irradiation for the prevention and treatment of aminoglycoside-induced vestibular ototoxicity. Materials and Methods: An organotypic culture of 2 to 4 days old rat utricular maculae hair cells was used. The cultured utricular hair cells were divided into 6 groups. Group C: the hair cells were cultured for 14 days. Group G: cultured hair cells were treated with 1 mM gentamicin (GM) for 48 hours. Group L: LLL irradiation with 670 nm diode laser 3 mW/cm~2 for 60 min (10.8 J/cm~2)/day for 14 days. Group LG: LLL irradiation 10.8 J/ cm~2/day for 2 days followed by GM insult. Group GL: treated with GM and followed by LLL irradiation 10.8 J/cm~2/day for 12 days. LGL group: LLL irradiation 10.8 J/ cm~2/day for 2 days, then GM insulted, followed by the LLLT 10.8 J/ cm~2/day for 10 days. The hair cells in each group were examined and counted by confocal laser scanning electron microscope on 7th and 14th days after FM1-43 staining and observed by scanning electron microscope (SEM). Results: The number of vestibular hair cells of group G was significantly less than those in group C. Group L showed no difference compared to group C. Significantly higher numbers of cells were seen in Group LG and GL comparing to group G. The cells were more in LG than group GL. Group LGL showed the most vestibular hair cells compared to the G, LG and GL groups. SEM showed damaged hair cells in group G while they were well preserved in groups C, L, LG. GL, and LGL. Conclusion: LLL irradiation before and after GM insult on utricular hair cells were most effective to prevent and treat GM ototoxicity. This study indicates that LLL irradiation may have clinical implications to treat various vestibular and cochlear inner ear diseases.