Figure 6

Fiber cell involvement in wound healing in Trichoplax. (a) Graph illustrating the time course of wound closure in a cut animal (wound length versus time) and a scheme of the experiment and stages of wound healing. Animals were cut in half. Five minutes after cutting, the wounded area (green) was slightly invaginated. The wound margins curled inwards and gradually became closer with intermittent reopenings. The margins met and fused by ~ 60 min, leaving a notch marking the site of the wound. (b, c) Fluorescence staining for fiber cells (anti-FC, green), mucocytes (WGA, red), and nuclei (Hoechst, blue) in intact and wounded Trichoplax. (b) In intact Trichoplax, tightly packed epithelial cells form a rim (bracket) around the circumference of the body. A row of mucocytes resides within the rim or close inside. Fiber cells (f) are arrayed in the interior starting ~ 10 µm from the edge. (c) In wounded Trichoplax, fiber cells are aligned along the wound and are more tightly packed and intensely stained than fiber cells in the interior or in intact animals. Inset (framed region) shows magnified view of fiber cells aligned along the wound.