Validation of an In Vitro Model to Study Human Cartilage Responses to Compression

The aim of this work was to develop an in vitro model to study mechanical compression effects on cartilage. A pressure-controlled compression device was used in this study. Cartilage explants obtained from human knee were compressed at 1MPa/1Hz for 7 hours (30 min ON, 30 min OFF) under normoxia (5% CO2, 21% O2) or hypoxia (5% CO2, 5% O2). Cell viability was analyzed while nitric oxide (NO) and glycosaminoglycans (GAG) release was assayed in culture media. Mechanical stimulation increased NO production and GAG release by human cartilage explants under normoxia and hypoxia culture. In normoxia and hypoxia conditions, mechanical stimulation alters human OA cartilage metabolism. There is also, an increase in matrix degradation after compression, as shown by levels of GAG found in culture media. This study put in evidence the importance of mechanical compression in the progression of the osteoarthritis and present and in vitro model for mechanobiological and pharmacological studies.