Photobiomodulation Can Enhance Stem Cell Viability in Cochlea with Auditory Neuropathy but Does Not Restore Hearing

Figure 4

Morphological changes in the cochlea after combination therapy with GFP-mESCs and PBM in a secondary neurodegeneration model. (a) Hematoxylin and eosin (H&E) staining after 2 weeks of combination therapy (10 weeks after KM surgery). The KM group showed cell damage. More viable cells were observed in the KM-SC-PBM group after combination treatment. (b) One of the KM-SC-PBM (box) treated mice showed deformed structure in all areas of the cochlea. ABR measurement of this animal showed that hearing was still impaired after the combination therapy. (c) Deformed KM-SC-PBM showed abnormal GFP expression in all cochlear regions after 2 weeks of combination therapy. A highly magnified epifluorescence image shows GFP expression in Rosenthal’s canal and in the scala media, scala tympani (ST), and scala vestibule (SV), suggesting that the SCs penetrated into various cochlear tissues. However, no neurofilament expression was observed, suggesting that the combination therapy had a biphasic effect. Scale bars = 50 µM (H&E) and 100 and 20 µM (IF = immunofluorescence).