A Simple Method for Visualization and Quantitative Evaluation of Single and Collective Cell Migration in Bright Field Microscopy Images

Cell migration is observed in various cases such as embryonic and lesion developments. The migration directly influences the phenomena around the migration path. Bright field microscopy, generally used for cell observation, is effective in tracking cell movement, but the detection of the cell outline via image processing methods partially fails. In this study, a simple method, utilizing the intensity fluctuation of the image caused by the passage of a cell as a parameter for evaluation of the cell movement, has been proposed to visualize the region where the cell passed and quantitatively evaluate its frequency by the fluctuation pattern. The map that depicts the activity of cell movement is created, and the geometrical characteristics of each region and fluctuation degree are quantitatively shown. Because detection of the cell outline is not necessary, this method is applicable to collective cells as well as single cells. When this method was applied to the images of hemocytes in Halocynthia roretzi (Ascidiacea), which were composed of single and collective cells and showed complex patterns in movement, the map and quantitative parameters for the fluctuation were successfully obtained. The method can be improved by the calibration of intensity distribution and applied to cells in various species.