Fig. 4.

Direct ocular exposure of mice to 10 μg PAO arsenical causes severe corneal and retinal injury. A: Both corneal and retinal tissues of the exposed mice demonstrated cytokine overexpression 24 h later measured as mRNA fold change (n = 3–6). B and C: Treatment with PAO results in the loss of retinal function. The ERG traces of treated and control eyes at two weeks post-treatment are shown (B, n = 12). The a- and b-wave amplitudes were significantly diminished in PAO-treated eyes during the four weeks after exposure (C n = 6). D: TUNEL-positive cells in the retina of PAO-treated mice are shown in green (left). The RGC, cells of the INL, and random photoreceptor cells (white arrows) demonstrated TUNEL-positive staining. The average of six superior and inferior fields of each control and experimental eyes was used to calculate the number of TUNEL-positive cells (in green) at two weeks post-treatment (n = 3). Nuclei were stained with DAPI. The blue color was substituted by red for better visualization. E: The scoring of the PAO-induced corneal injury using the Draize test is shown. Major changes in the cornea and conjunctiva occurred during the first two weeks after exposure. Then, the degree of the damage remained the same. F: Thus, the corneal thickness increased more than five-fold in the PAO-treated eyes at two week after exposure (n = 5). *p < 0.05, **p < 0.01, ***p < 0.001, and ****p < 0.0001. Scale bar is 50 μm