Effects of chondroitin sulfate and interleukin-1 beta on human chondrocytecultures exposed to pressurization: a biochemical and morphological study

Objective: This study investigated the in vitro effects of chondroitin sulf ate (CS) on human articular chondrocytes cultivated in the presence or in t he absence of interleukin-1 beta (IL-1 beta) during 10 days of culture with and without pressurization cycles. Design: The effects of CS (10 and 100 mu g/ml) with and without IL-1 beta w ere assessed in the culture medium of cells exposed to pressurization cycle s in the form of synusoidal waves (minimum pressure 1 Mpa, maximum pressure 5 Mpa) and a frequency of 0.25 Hz for 3 h by immunoenzymatic method on mic roplates for the quantitative measurement of human proteoglycans (PG). On t he 4th and 10th day of culture the cells were used for morphological analys is by transmission electron microscopy (TEM) and scanning electron microsco py (SEM). Results: The presence of IL-1 beta determines a significant decrease in PG concentration measured in the culture medium. When the cells are cultured i n the presence of IL-1 beta and CS, a statistically significant restoration of PG levels is observed. Under pressurization conditions, we observed tha t PG concentration in the medium of cells presents a significant increase a t baseline conditions, in the presence of IL-1 beta+CS10 and IL-1 beta+CS10 0, but not with IL-1 beta alone. The results concerning metabolic evaluatio n are confirmed by the morphologic findings obtained by TEM and SEM. Conclusions: These in vitro studies confirm the protective role of CS, whic h counteracts the IL-1 beta induced effects and they confirm the importance of pressure on chondrocyte metabolism and morphology. (C) 2000 OsteoArthri tis Research Society international.