The comet assay is a sensitive method to detect physical breaks in DNA on a single-cell level. In this assay, cells are first embedded in agarose, lysed, and then subjected to electrophoresis. Fragmented or damaged DNA migrates faster than intact DNA and resembles a comet, with the length and intensity of tail indicating the extent of damage.

This image/experiment told us that mice with Alzheimer’s disease have more DNA breaks in the brain cells, relative to control mice. Our goal is to enhance DNA repair and to see if that improves cognitive function in AD mice.