Image Correlation Spectroscopy Reveals Global Dynamics of Wound Healing

Abstract

We apply techniques based on correlation spectroscopy to quantify cell migration during wound re-epithelialization in an axolotl wound healing model. We show that cell hypertrophy (about 37% in volume) is present from the time of injury and continues throughout re-epithelialization. Our combined imaging techniques (transmission and laser scanning fluorescence) microscopy and analysis algorithms (Image Correlation Spectroscopy and Spatio-Temporal Image Correlation Spectroscopy) allow us to determine this complex sequence of events from the point of injury until the re-epithelialization is complete. Using non-invasive optical sectioning, we determine that the basal keratinocytes migrate into the wound bed faster than the suprabasal keratinocytes. Additionally, Image Correlation Spectroscopy (ICS) reveals cell hypertrophy as there is an increase in width of the spatial autocorrelation function as a function. Using camera based transmission microscopy, we observe that the enlarged cells produce a point of dislocation that foreshadows and dictates the initial direction of the migrating cells. Globally, the cells follow a concerted vortex motion that is maintained after the wound is fully re-epithelialized. Using Spatio-Temporal Image Correlation Spectroscopy (STICS), we quantify the velocities of the cells undergoing this spiral motion. Closer examination reveals that there is a transition from a chaotic state to a highly organized cohesive motion. This transition is seen in as little as 1 hour post injury. Our results suggest that geometrical constraints combined with the observed cell hypertrophy may dictate the mechanism by which cells repopulate the wound bed.