Transmeatal Low Level Laser Therapy (LLLT) on Vestibular Inner Ear after Topical Gentamicin Ototoxicity

Abstract

Background and ObjectivesThe objectives of this study is to evaluate any adverse effects on outer and inner ear structures after transmeatal low level laser therapy (LLLT) and to see the effects of transmeatal LLLT on gentamicin induced unilateral vestibulopathy in guinea pigs. Materials and MethodsWe measured penetration rate of transmeatal low level laser (LLL) into the perilymphatic space of cochlea through a tympanic membrane, cochlea wall and hearing level post transmeatal LLLT were measured. Histopathologic studies on ear canal skin and ear drum were performed for observation of any damage by LLLT. Guinea pigs were then divided into control and LLLT group. Both groups received injection of gentamicin (GM) into the left middle ear. LLLT group were irradiated into the left ear through the external ear canal for 5 days starting 1 day after GM injection into the left ear. The animals underwent sinusoidal oscillation about a vertical and off vertical axis 5 days post GM injection. ResultsNo damage on ear canal skin and ear drum was noted and hearing remained normal after LLLT. The penetration rate of LLL through the drum was 8% and 5% of LLL penetrated into the perilymphatic space. The left side gains of the control group were significantly decreased compared to the left side gain of the LLLT group. The gains of the right ear in both groups were not significantly different. ConclusionThis study demonstrated that transmeatal LLLT restores vestibular function in guinea pigs with gentamicin induced ototoxic dysfunction. LLLT may have clinical implications in the treatment of various vestibular diseases with vestibular dysfunction.

Effect of Low-level Laser Therapy on Propylthiouracil-induced Hypothyroidism Model Mice: A Pilot Study

“…Several studies have reported that LLLT is effective in various fields, including treatment of alopecia, 16 vestibulopathy, 17 and ophthalmic diseases. 18,19 However, the mechanism of LLLT has not been fully elucidated.…”