Aging Mice (IMAGE) University of Pennsylvania School of Medicine Caption In response to irradiation, normal mice (left) show massive hair graying, while mice deficient in triggering inflammation (right) do not show gray hair. Credit Maria Grazia Vizioli and Zhixun Dou, Perelman School of Medicine, University of Pennsylvania Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.