Background An altered chondrocytes phenotipic expression of biglycan and decorin is an early event in osteoarthritis (OA). Changes in extracellular matrix sodium concentration ([Na+]) occurs in OA. Previous results suggested that chondrocytes are sensitive to changes in their extracellular [Na+] environment and respond with variations in the matrix synthesis.
Objectives Here we have studied the influence of extracellular [Na+] on the metabolism of small proteoglycans, biglycan and decorin, in a human chondrocyte-like cell line, C20/A4.
Methods Extracellular deposition of biglycan and decorin was analysed in C20A4 cells cultured: 1) inmunohistochemically using specific antibodies against biglycan and decorin and secondary IFTC conjugated antibodies; and 2) in SDS-PAGE electrophoresis and blotting using the corresponding antibodies.
Results Fluorescence inmunohistochemically shows specific extracellular expression of biglycan and decorin in chondrocytes cultured in estandard [Na+] (154 nm) and western blotting intensities of these small proteoglycans varied with [Na+].
Conclusion This study demostrates that biglycan and decorin are expressed in the human chondrocyte cell line C20A4. We are now searching if [Na+] variations is able to produce cualitative or cuantitative alterations in the matrix synthesis as it have been found in osteoarthritis.
-Supported by FIS grant 99/0695-