Effect of low-level laser therapy on cochlear hair cell recovery after gentamicin-induced ototoxicity
- 441 Downloads
Cochlear hair cells are the sensory receptors of the auditory system. It is well established that antibiotic drugs such as gentamicin can damage hair cells and cause hearing loss. Rescuing hair cells after ototoxic injury is an important issue in hearing recovery. Although many studies have indicated a positive effect of low-level laser therapy (LLLT) on neural cell survival, there has been no study on the effects of LLLT on cochlear hair cells. Therefore, the aim of this study was to elucidate the effects of LLLT on hair cell survival following gentamicin exposure in organotypic cultures of the cochlea of rats. The cochlea cultures were then divided into a control group (n = 8), a laser-only group (n = 8), a gentamicin-only group (n = 8) and a gentamicin plus laser group (n = 7). The control cultures were allowed to grow continuously for 11 days. The laser-only cultures were irradiated with a laser with a wavelength of 810 nm at 8 mW/cm2 for 60 min per day (0.48 J/cm2) for 6 days. The gentamicin groups were exposed to 1 mM gentamicin for 48 h and allowed to recover (gentamicin-only group) or allowed to recover with daily irradiation (gentamicin plus laser group). The hair cells in all groups were stained with FM1-43 and counted every 3 days. The number of hair cells was significantly larger in the gentamicin plus laser group than in the gentamicin-only group. The number of hair cells was larger in the laser-only group than in the control group, but the difference did not reach statistical significance. These results suggest that LLLT may promote hair cell survival following gentamicin damage in the cochlea. This is the first study in the literature that has demonstrated the beneficial effect of LLLT on the recovery of cochlear hair cells.
KeywordsLow-level laser therapy Cochlea explants Hair cell Regeneration Hearing loss
This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2010–0024301).
Conflicts of Interest
- 1.FDA (2009) Application K081166. Food and Drug Administration, Rockville, MDGoogle Scholar
- 2.FDA (2002) Application K020657. Food and Drug Administration, Rockville, MDGoogle Scholar
- 3.FDA (2003) Application K030226. Food and Drug Administration, Rockville, MDGoogle Scholar
- 4.FDA (2010) Application K091496. Food and Drug Administration. Silver Spring, MDGoogle Scholar
- 6.Oron A, Oron U, Chen J, Eilam A, Zhang C, Sadeh M, Lampl Y, Streeter J, DeTaboada L, Chopp M (2006) Low-level laser therapy applied transcranially to rats after induction of stroke significantly reduces long-term neurological deficits. Stroke 37(10):2620–2624. doi: 10.1161/01.STR.0000242775.14642.b8 PubMedCrossRefGoogle Scholar
- 8.Lapchak PA, Salgado KF, Chao CH, Zivin JA (2007) Transcranial near-infrared light therapy improves motor function following embolic strokes in rabbits: an extended therapeutic window study using continuous and pulse frequency delivery modes. Neuroscience 148(4):907–914. doi: 10.1016/j.neuroscience.2007.07.002 PubMedCrossRefGoogle Scholar
- 11.Zivin JA, Albers GW, Bornstein N, Chippendale T, Dahlof B, Devlin T, Fisher M, Hacke W, Holt W, Ilic S, Kasner S, Lew R, Nash M, Perez J, Rymer M, Schellinger P, Schneider D, Schwab S, Veltkamp R, Walker M, Streeter J (2009) Effectiveness and safety of transcranial laser therapy for acute ischemic stroke. Stroke 40(4):1359–1364. doi: 10.1161/STROKEAHA.109.547547 PubMedCrossRefGoogle Scholar
- 17.Chung YW, Ahn JC, Lim ES, Kim YS, Lee SH, Lee MY, Rhee CK (2007) A promotive effect of low-level laser on hair cell regeneration following gentamicin induced ototoxicity in postnatal organotypic culture of rat utricles. Korean J Otolaryngol-Head Neck Surg 50(1):25–30Google Scholar