MIPSY: Real-time morphometry to quantify the time course of rapid epithelial restitution

Summary The gastrointestinal mucosa has the ability to repair itself rapidly following superficial mucosal injury by rapid restitution. The mechanism epithelial consists of cell migration amddoes not involve mitosis. This study reports the mechanisms of rapid epithelial restitution in the colon in vivo and in the human colon in vitro, describes a new computerized real-time morphomytry system to investigate the time course of restitution and presents a new method to calculate the migration speed of epithelia during the repair process. Superficial mucosal damage to the rabbit colon in vivo was produced by luminal exposure to 100 nM HCl for 5 min (80% of mucosal surface), a comparable injury in the human colon in vitro was obtained by luminal exposure to 10 mM HCl for 10 min (96% of mucosal surface). After detachment of the damaged tissue the intact epithelial cells in the vicinity of the necrosis extended pseudopodia and migrated over the denuded basal lamina. The morphological appearance of rapid epithelial restitution was the same in the rabbit and the human, only the time course was postponed in the human. The time course of rapid restitution was assessed by a newly developed computerized morphometry system (MIPSY). When tissues were examined after various time points following acid damage, 61% of the mucosa were damaged in the rabbit after 1 h, after 2 hs and 20% after 5hs. In the human colon 85% of the mucusal surface were damaged after 2 hs and 20% 5 hs after the end of acid exposure. The distinct morphology of the rabbit colon allowed the calculation of the migration speed epithelial cells (~2–3 µm/min) using MIPSY. We conclude that rapid epithelial restitutiun is a basic defense mechanism that does not only exist under facultatively hostile conditions like in the stomach amd the duodenum, but also in the colon and especially in the human tissue, too. A real-time morpbometry equipment is a necessary tool to objectify the time course rapid restitution.