The use of a non-ionic surfactant (P188) to save chondrocytes from necrosis following impact loading of chondral explants

Abstract

While current injury criteria for the automotive industry are based on bone fracture, the majority of knee injuries suffered in collisions each year do not involve fracture of bone. Instead, clinical studies of traumatic joint injury often document early pain and development of chronic diseases, such as osteoarthritis. Previous studies suggest chronic disease can be initiated by cell death that occurs in articular cartilage during mechanical trauma to the joint. In the current investigation early necrosis of chondrocytes was investigated after blunt trauma to chondral explants. A non-ionic surfactant (P188) was explored as a potential tool for early intervention into the disease process, as this surfactant has been shown to repair damaged membranes in other cell lines. Three groups of adult bovine chondral explants were equilibrated for 48 h in culture media. Two groups were then loaded to 25 MPa in unconfined compression. Half the specimens in each group were incubated in media supplemented with 8 mg/ml P188 immediately after loading, while the other half was returned to standard media. At 1 and 24 h the percentages of live and dead cells in compressed and control groups were determined with a cell viability stain. At 1 h post-trauma, P188 incubated specimens had a significantly increased percentage of live cells in the superficial zone versus the no-P188 group. At 24 h the percentages of live cells in all three zones of the P188-treated explants were significantly greater than in the no treatment group. This study showed that P188 surfactant could help restore the integrity of cell membranes in cartilage damaged by blunt mechanical trauma. With the ability of P188 to "save" chondrocytes from early necrotic death using in vitro chondral explants, its role in prevention of a post-traumatic osteoarthritis in a diarthrodial joint should be further explored using in vivo animal models.