Bone Cells (IMAGE) University of Wisconsin-Madison Caption Micrographs show the difference between treated and untreated bone cells in a mouse model of severe bone loss. Wisconsin researchers have identified two native protein factors that help keep mesenchymal stem cells -- the master cells that make bone and cartilage -- happy in the laboratory dish. The work could one day help make regenerating lost bone in patients a reality. Credit Wan-Ju Li 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.