Photobiomodulation by laser therapy rescued auditory neuropathy induced by ouabain.
Auditory neuropathy is a hearing disorder caused by impaired auditory nerve function. The lack of information about the pathophysiology of this disease limits early diagnosis and further treatment. Laser therapy is a novel approach to enhance nerve growth or induce axonal regeneration. We induced auditory neural degeneration sparing the sensory epithelium with local ouabain application in an animal model and observed the rescue effect of photobiomodulation (PBM), showing recovered auditory function and favorable histologic outcome. Hearing was evaluated using the auditory brainstem response (ABR) and distortion product otoacoustic emission (DPOAE). Seven days after ouabain application, the animals were sacrificed to evaluate the morphological changes. DPOAE change was not observed in all groups after ouabain application indicating no changes of outer hair cell function. Ouabain application increased the ABR thresholds increase, while the use of ouabain plus laser produced lower threshold compared to the ouabain group. Hematoxylin and Eosin staining of cochlea mid-modiolar sections in animals treated with ouabain showed damaged spiral ganglion cells, neurofilaments, and post synaptic puncta. Ouabain plus laser group showed higher number of spiral ganglion cells, higher density of neurofilaments, and higher number post synaptic puncta counts compared with ouabain application group. Short-term application of ouabain caused spiral ganglion cell damage while sparing the inner and outer hair cells in gerbils. Photobiomodulation alleviated the hearing loss caused by ouabain induced auditory neuropathy. The results indicate the possible role of photobiomodulation therapy for inner ear diseases accompanied by spiral ganglion degeneration.
Department of Otolaryngology-Head & Neck Surgery, Dankook University Hospital, Cheonan, Republic of Korea.
Min Young
MY
Lee
Department of Otolaryngology-Head & Neck Surgery, Dankook University Hospital, Cheonan, Republic of Korea.
Seung-Hyun
SH
Bae
Backman Laser Institute-Korea, Dankook University College of Medicine, Cheonan, Republic of Korea.
So-Young
SY
Chang
Department of Otolaryngology-Head & Neck Surgery, Dankook University Hospital, Cheonan, Republic of Korea.
Jae-Hun
JH
Lee
Department of Otolaryngology-Head & Neck Surgery, Jeju National University College of Medicine, Jeju, Republic of Korea.
Se-Hyung
SH
Kim
Department of Biomedical Science, Dankook University College of Medicine, Cheonan, Republic of Korea.
Jin-Chul
JC
Ahn
Department of Otolaryngology-Head & Neck Surgery, Dankook University Hospital, Cheonan, Republic of Korea; Backman Laser Institute-Korea, Dankook University College of Medicine, Cheonan, Republic of Korea.
Phil-Sang
PS
Chung
Beckman Laser Institute and Medical Clinic, University of California, Irvine, 1002 Health Sciences Rd., Irvine CA 92612, USA.
Wesley
W
Moy
Department of Otolaryngology-Head & Neck Surgery, Dankook University Hospital, Cheonan, Republic of Korea; Backman Laser Institute-Korea, Dankook University College of Medicine, Cheonan, Republic of Korea. Electronic address: jjkingy2k@gmail.com.
Jae Yun
JY
Jung
D000818:Animals; D002452:Cell Count; D016057:Evoked Potentials, Auditory, Brain Stem; D005260:Female; D005849:Gerbillinae; D006313:Hearing Loss, Central / Q000473:pathology / Q000503:physiopathology / Q000532:radiotherapy*; D028022:Low-Level Light Therapy; D009412:Nerve Fibers / Q000473:pathology; D009474:Neurons / Q000473:pathology; D010042:Ouabain; D013136:Spiral Ganglion / Q000473:pathology; D013569:Synapses / Q000473:pathology
D010042:Ouabain
ABR; Ouabain; Photobiomodulation; Spiral ganglion neurons; Synaptic puncta