B.S. (Bachelor of Science)
Department of Biological Sciences
The impacts of microscopy image analysis have resulted in better visualization of foci (spots) in cell nuclei. However, manual analysis of microscopy images is challenging regarding subjectivity in structure counting and identification. Recent computer algorithms have enabled cellular analysis through automatic segmentation that uses computational edges in digital images. In this project, the automatic segmentation workflow in the Zeiss Zen Blue 3.3 software was adapted to more closely reflect visualized foci in a cell. The foci represent DNA double strand breaks. The Zeiss LSM 900 microscope was used to collect maximal intensity projection images of γH2AX foci and super-resolution z-stacks (z = 1 μm). The Zeiss Zen Blue 3.3 software was used to automatically score γH2AX foci using global thresholding and background subtraction segmentation. After single U87 cell segmentation analysis, 8 Gy irradiated male and female mouse brain sections were automatically scored using the background subtraction method. Manual scoring of cell nuclei in mouse brain sections was used to calculate foci density (foci per cell) in male and female sections. Increased γH2AX foci counts were observed in the irradiated male and female brain sections, which indicates the persistence of DNA lesions past normal DNA repair times. Irradiated male mice showed higher foci count and foci density compared to female mice, supporting established literature of increased male radiosensitivity. Automatic segmentation has the potential to provide an accurate and time-efficient method for foci scoring with further implementation to improve understanding of radiation-induced DNA damage for bettering therapeutic approaches toward males and females.
Cirone, Nicholas, "Segmentation of DNA Lesions in Irradiated Mouse Brain Sections" (2022). Honors Capstones. 1411.