Fig. 4

PM2.5 triggers activation of the LSPCs at the early exposure stage. (A) H&E staining showed PM2.5 led to corneal epithelium thickening after 2 days of exposure. N = 6 in each group. No significant changes were observed in limbal epithelial thickness. N = 6 in each group. ***p < 0.001. (B) Ki67⁺ cells increased on rat corneal and limbal epithelial after exposure to PM2.5 for 2 days (scale bar, 100 μm). N = 3 in each group. White arrowhead points to the Ki67⁺ cells. *p < 0.05, **p < 0.01. (C) K12 significantly increased on rat limbus after PM2.5 exposure for 2 days, suggesting active differentiation was induced at an early stage (scale bar, 100 μm). N = 4 in each group. *p < 0.05. (D) PM2.5 triggers the activation of the LSPCs at the early exposure stage and increases the proliferation and differentiation of LSPCs. PBS: the PBS eyedrop administration group; PM: the PM2.5 eyedrop administration group; LSPCs: Limbal stem/progenitor cells; K12: Keratin12