Confocal microscopic view of eNOS and nNOS after HBOT. Immunofluorescence labeling of eNOS (red) and nNOS (green) in the spiral ganglion (A-C), cochlear modiolus (D-F) and stria vascularis (G-I) of the cochlea after repetitive HBOT. Co-expression of eNOS and nNOS occurred in the spiral ganglion (C) and stria vascularis (I). In the cochlear modiolus, nNOS was expressed in the modiolar nerve fibers, and eNOS was expressed along the modiolar blood vessel. Scale bar, 20 μm.