Gianna Leon

Osteoarthritis is the leading cause of physical disability and significantly reduces the patient's quality of life. While no single factor determines whether or not someone will develop osteoarthritis, ligament injury drastically increases the probability of osteoarthritis development later on in life by permanently destabilizing the joint it is supporting. Mammals have a poor regenerative response once a ligament is injured, healing with scar tissue instead of ligament cells. This scar tissue increases the risk of re-injury and does not properly restabilize the joint due to its composition of disorganized, dense fibroblasts. Zebrafish have the unique capacity to heal their ligaments without scarring, providing a means to study how they can regenerate. To understand whether or not this capability to regenerate ligament is intrinsic (healed by existing ligamentocytes only) or extrinsic (healed by another cell type), this project focused on quantifying the proliferation and apoptosis of the interopercular mandibular ligament cells and the surrounding tissues. In order to carry out this experiment, proliferating cell nuclear antigen was used to label proliferating cell nuclei and ApopTag to label nicked DNA in apoptotic (dying) cells. It was found that though there was no significant difference apoptosis across regeneration, apoptosis was visible in vivo imaging. Additionally, proliferation was increased by 3dplt.  Using these assays to determine the lineage of the regenerated ligament led to a better understanding of the cell types that allowed zebrafish to regenerate their ligaments, which may then be implemented in mice and eventually humans.

Research Paper

2023 JSHS Metro Region Semifinalist