Photobiomodulation (PBM) has been suggested to have a therapeutic effect on irreversible hearing loss induced by aminoglycosides, including gentamicin (GM). However, its intracellular mechanism(s) in GM-induced ototoxicity remain poorly understood. In the present study, we investigated the effect of PBM in GM-induced ototoxicity in auditory cells. We tried to characterize the downstream process by PBM, and the process that triggered the increased cell viability of auditory cells. As a result, the effects of PBM against GM-induced ototoxicity by increasing ATP levels and mitochondrial membrane potential was confirmed. These results suggest a theory to explain the therapeutic effects and support the use of PBM for aminoglycoside-induced hearing loss.

Background: Temporal lobe epilepsy (TLE) remains one of the most drug-resistant focal epilepsies. Glutamate excitotoxicity and neuroinflammation which leads to loss of synaptic proteins and neuronal death appear to represent a pathogen that characterizes the neurobiology of TLE. Photobiomodulation (PBM) is a rapidly growing therapy for the attenuation of neuronal degeneration harboring non-invasiveness benefits. However, the detailed effects of PBM on excitotoxicity or neuroinflammation remain unclear. We investigated whether tPBM exerts neuroprotective effects on hippocampal neurons in epilepsy mouse model by regulating synapse and synapse-related genes.Methods: In an in vitro study, we performed imaging analysis and western blot in primary hippocampal neurons from embryonic (E17) rat pups. In an in vivo study, RNA sequencing was performed to identify the gene regulatory by PBM. Histological stain and immunohistochemistry analyses were used to assess synaptic connections, neuroinflammation and neuronal survival. Behavioral tests were used to evaluate the effects of PBM on cognitive functions.Results: PBM was upregulated synaptic connections in an in vitro. In addition, it was confirmed that transcranial PBM reduced synaptic degeneration, neuronal apoptosis, and neuroinflammation in an in vivo. These effects of PBM were supported by RNA sequencing results showing the relation of PBM with gene regulatory networks of neuronal functions. Specifically, Nlgn3 showed increase after PBM and silencing the Nlgn3 reversed the positive effect of PBM in in vitro. Lastly, behavioral alterations including hypoactivity, anxiety and impaired memory were recovered along with the reduction of seizure score in PBM-treated mice.Conclusions: Our findings demonstrate that PBM attenuates epileptic excitotoxicity, neurodegeneration and cognitive decline induced by TLE through inhibition of the Nlgn3 gene decrease induced by excitotoxicity.Graphical

Genetic hearing loss crosses almost all the categories of hearing loss which includes the following: conductive, sensory, and neural; syndromic and nonsyndromic; congenital, progressive, and adult onset; high-frequency, low-frequency, or mixed frequency; mild or profound; and recessive, dominant, or sex-linked. Genes play a role in almost half of all cases of hearing loss but effective treatment options are very limited. Genetic hearing loss is considered to be extremely genetically heterogeneous. The advancements in genomics have been instrumental to the identification of more than 6,000 causative variants in more than 150 genes causing hearing loss. Identification of genes for hearing impairment provides an increased insight into the normal development and function of cells in the auditory system. These defective genes will ultimately be important therapeutic targets. However, the auditory system is extremely complex which requires tremendous advances in gene therapy including gene vectors, routes of administration, and therapeutic approaches. This review summarizes and discusses recent advances in elucidating the genomics of genetic hearing loss and technologies aimed at developing a gene therapy that may become a treatment option for in the near future.

This study was designed to evaluate the normal development of the nasal septum in Koreans using sagittal MRI for the valuable clinical information on septal procedures. Two hundred eighty patients who had their whole nasal septum visualized in the midline sagittal view were selected among the 3,904 patients with brain MRI from January, 2004 to December, 2006 at Dankook University Hospital. The patients who had a history of nasal septal surgery or nasal trauma were excluded. Following parameters are calculated and analyzed: lengths of bony and cartilage dorsum and septal cartilage-nasal bone overlap, total septal area, septal cartilage area and, the proportion of the cartilage area to septal area and the maximal harvestable cartilage for grafting were calculated using the PAC program. All the parameters were increased until adolescence. Thereafter, bony dorsal length, cartilage dorsal length, total dorsal length, total septal area and maximal harvestable cartilage for grafting have not changed significantly with age, while SC-NB overlap length, septal cartilage area, and proportion of the cartilage area to the total septal area were significantly decreased with age. The SC-NB overlap length was positively correlated with the septal cartilage area and the proportion of the cartilage area to the total septal area. The small septal cartilage area and its proportion to the total septal area were significantly correlated with a short overlap length of the septal cartilage under the nasal bone. Septal procedures should be carefully performed in the elderly due to the risk of incurring saddle nose.

Conclusion: Seven-day administration of systemic steroids was more effective in preserving hearing for 12 weeks after cochlear implantation (CI) than a 3-day delivery. Objectives: To determine the effectiveness of extended delivery of systemic steroids to preserve hearing in guinea pigs after CI. Methods: Dexamethasone (4 mg/ml) was delivered parenterally via a mini-osmotic pump for either 3 or 7 days. A dummy CI electrode was inserted via cochleostomy approach in 8-week-old guinea pigs. Auditory thresholds were assessed from tone burst auditory brainstem responses (2, 8, 16, 24, and 32 kHz) at 1 day prior to CI, and 1, 4, and 12 weeks after implantation. Histologic evaluation of the cochleae was carried out. Results: No differences were observed in hearing thresholds among groups before CI. Significant hearing preservation was achieved at 8, 16, 24, and 32 kHz only in the 7-day infusion group compared with the control group at 1 week after CI. The same trend was maintained at 4 weeks (16, 24 kHz) and 12 weeks (16, 24, and 32 kHz). Histologic review of the 7-day infusion group revealed less fibrosis and ossification in the scala tympani and the preservation of more spiral ganglion cells, compared with the control group.