The Impact of Mechanical Load on Regenerative Responses in Knee Articular Cartilage

Kelsey Richard



Osteoarthritis (OA) is the most common cause of disability in older adults as 10-15% of adults over 60 have some degree of OA. The treatment options for OA are limited and lacking in effective long-term solutions. One major reason for the debilitating nature of this illness is the inability of cartilage to effectively repair itself. Low energy, load-bearing exercise is beneficial for joint health; However, the molecular response to this exercise is not adequately studied. Within the articular cartilage, there is a subpopulation of chondrogenic progenitor cells that can initiate cartilage growth, but the signals that activate these cells are unclear. EGFR signaling has previously been implicated as a regulatory molecule during OA progression and could play a role in progenitor cell activation.

The goal of my project is to better understand the molecular mechanisms that initiate cartilage regrowth, which could lead to improved treatment outcomes for patients with articular cartilage damage. Bovine articular cartilage explants were subjected to low energy impact load using a mechanical loading device. Samples were then cultured, fixed, sectioned, and subjected to Alcian Blue, Safranin-O staining, and Immunohistochemistry in order to evaluate molecular responses. We found that low energy impact loading resulted in an anabolic response in the articular cartilage of bovine joints by stimulating endogenous resident chondrocyte progenitors to make new cartilage tissue; this process involves EGFR signal activation within progenitor cells. These results lead us to better understand the mechanisms behind cartilage regeneration and bring us closer to developing a targeted OA treatment.