Figure 3. Apoptotic cell death of the lens epithelium is an early feature of cataract culture

Induction of apoptotic cell death in lenses growing in ex vivo cataract culture was determined at culture day 2 at the time point prior to the appearance of lens opacities, by TUNEL assay (B-D, red). Panel A is a low power image of the lens section examined in this study in which nuclei were labeled by DAPI (blue) and the regions observed for TUNEL staining in B-D indicated by white-outlined boxes. Note that in the area in Box B, the equatorial zone, the lens section is flipped over. The images in B-D are overlays of DAPI (blue) and TUNEL (red) staining of the lens regions indicated in A: (B) anterior epithelium, (C) equatorial epithelium and (D) cortical fiber zones. TUNEL positive nuclei were present in both the anterior and equatorial epithelia of these lenses at culture day 2, preceding the formation of cortical opacities. No apoptosis was detected in the cortical region of the lens at day 2, a feature that was maintained throughout the 10-day culture period.