Figure 2. Expression of cell cycle markers. Cell bodies in the inner nuclear layer (INL) reentered the cell cycle, began to proliferate, and migrated to the ONL following laser injury. The cell cycle marker Cyclin D1 and the Müller cell nuclear marker and cell cycle marker Cyclin D3 were used to identify proliferative cells. Cyclin D1 staining was elevated within 24 h after laser injury and localized within the injury site only. Cyclin D3 expression was increased at days 2 and 3 postinjury (H,I). Positive cells normally found in the INL were now located in the outer nuclear layer, indicated by arrows H and I (ONL; H-J). The scale bars represent 75 μm.