Figure 5

DNA fragmentation in the inner ear cells at 7 d post-exposure to the AgNPs. 4000 μg/ml AgNP caused DNA fragmentation in the cells in the vestibule (a, b), stria vascularis (d-f), Reissner’s membrane (RM) (d, f), and spiral ligament (SL in d-f). In the lateral wall of second higher turn (Coch-LW2ndH), limited marginal cells (StrMC) in the stria vascularis and sparse fibrocytes in the spiral ligament (SL) showed DNA fragmentation (f). 200 μg/ml AgNP caused DNA fragmentation in cells in osseous spiral lamina (OSL in h), cells in the cochlear capillary (Cap in I), and hair cells of the cochlear Corti’s organ (Coch-CO)(G). Water did not cause significant DNA fragmentation in the vestibule (c). No staining was demonstrated in the negative control by omitting the labeling solution. Percentages of positive staining were 74%, 66%, 0%, 53%, and 59% in a, b, c, d, and E respectively. Coch-LW1stL: lateral wall of the cochlear lower basal turn; Coch-LW2ndL: lateral wall of the cochlear lower second turn; Coch-LW2ndH: lateral wall of the cochlear higher second turn; Enth: endothelial cells; Epth: epithelial cells; PC: pericytes of the Cap; Vest-Am: ampulla in the vestibule; Vest-Sa: saccule in the vestibule. Scale bars = 24.8 μm in a-f, h, j, and 10 μm in g and i.