The complexity of keratocyte migration in salmon explant cultures: initial results and future prospects

Intact skin is of uttermost importance for fish welfare. The fish skin provides an environmental barrier and protects against invading pathogens. However, both pathogens and physical insults cause skin wounds that are of major concern in modern fish farming. The behavior and interactions between keratocyte cells and sheets of cells are not well understood. The collective migration of keratocytes (skin epithelial cells) is of central importance for wound healing in fish. In this study, we aimed to elucidate the complex wound healing process in fish skin by studying in vitro cultures of these highly motile cells. Using explant cultures from farmed Atlantic salmon (Salmo salar) and differential interference contrast microscopy (DIC), we have captured the dynamics of sheets of cells from harvested fish scales and of individual cells interacting in the cell sheet vicinity. In addition to direct contact, the cells were observed to interact through long membrane tubes, turn, rotate, merge, and/or detach. Additionally, stationary cells and cells moving on top of the cell sheets were observed. Cell sheets approaching one another from different scales did not merge but dispersed.