Effect of continuous high hydrostatic pressure on the morphology and cytoskeleton of normal and osteoarthritic human chondrocytes cultivated in alginate gels

Objective: To investigate the effect of continuous high hydrostatic pressure on the cell ultrastructure and cytoskeleton of cultivated normal and osteoarthritic (OA) human chondrocytes. Methods: The effects of continuous hydrostatic pressure (24 MPa) for 3 hrs on normal and OA chondrocytes were assessed by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and immunofluorescence microscopy (IF). Results: Structural differences at the nuclear cytoplasmic and cytoskeletal levels were observed between normal and OA chondrocytes. Continuous high hydrostatic pressure severely altered normal chondrocytes that became similar in structural organization to OA chondrocytes and further reduced the number of cell organelles involved in the synthesis of collagen and proteoglycans. IF showed major changes in the distribution of actin and tubulin after pressurization in normal and OA chondrocytes. Conclusions: The results confirm the major role of pressure on chondrocyte ultrastructure. Continuous high hydrostatic pressure caused structural alterations in normal chondrocytes, which obtained similar, if not identical, characteristics to those typical of osteoarthritic chondrocytes. © Copyright Clinical and Experimental Rheumatology 2005.