Figure 5. Assessment of TM cell viability by calcein AM/PI co-labelling.

Viable trabecular meshwork (TM) cells exposed to calcein AM showed bright green fluorescence, while dead TM cells allowed PI to enter cell membrane and label the cell nuclear with red fluorescence. In the control group, most TM cells were still viable after perfusion for two weeks (A–C). In contrast, cells, including many nuclei, were destroyed by freeze-thaw. No calcein AM, and only a few PI-labeled TM cells were found (D–F). Different from the other two groups, a few TM cells were still alive in the saponin-treated group, but most of them were labeled as dead cells by PI (G–I). The different microscopy depths are approximate samples from the uveal (A), corneoscleral (D) and cribriform layer (G) in this flat mount.