Articular chondrocytes and synoviocytes in a co-culture system: influence on reactive oxygen species-induced cytotoxicity and lipid peroxidation.
OBJECTIVE
A new co-culture system of rat articular chondrocytes and synoviocytes (HIG-82; cell line) was incubated with phorbol myristate acetate (PMA), H2O2 or a combination of Fe2+ and ascorbic acid to simulate inflammation-like radical attacks in articular joints.


METHODS
Chondrocytes were characterized by immunocytochemistry against collagen type II, transmission electron (TEM) and light microscopy. Lipid peroxidation was investigated by measuring thiobarbituric-acid-reactive material in the supernatants, cytotoxicity by determining release of lactate dehydrogenase and proliferation by measuring [3H]thymidine incorporation, culture protein and DNA.


RESULTS
PMA or Fe2+ and ascorbic acid induced lipid peroxidation in chondrocytes and synoviocytes that was decreased significantly in co-cultures. PMA and H2O2 dose dependently induced release of lactate dehydrogenase in chondrocytes, which was lowered in co-cultures or in previously co-cultured chondrocytes to a nearly basal level. In contrast, conditioned media of synoviocyte cultures showed no lowering effect on the radical-induced toxicity. Protection against H2O2-induced damage of cellular membranes by co-culturing was also shown by TEM. Synoviocytes released chondrocyte-stimulating growth factors spontaneously without previous interaction.


CONCLUSIONS
Chondrocytes establish protective mechanisms against reactive oxygen species via an interaction with synoviocytes. Our co-culture model presents a possible way to study mechanisms of inflammation in articular joints under defined conditions.
Kurz
B
B
Anatomisches Institut der Universität Kiel, Olshausenstrasse 40, D-24098 Kiel, Germany. bkurz@anat.uni-keil.de
Steinhagen
J
J
Schünke
M
M
D000818:Animals; D002450:Cell Communication; D019902:Chondrocytes / Q000378:metabolism / Q000473:pathology*; D018920:Coculture Techniques; D007150:Immunohistochemistry; D007770:L-Lactate Dehydrogenase; D015227:Lipid Peroxidation; D008854:Microscopy, Electron; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013583:Synovial Membrane / Q000166:cytology; D013858:Thiobarbiturates
D017382:Reactive Oxygen Species; D013858:Thiobarbiturates; D007770:L-Lactate Dehydrogenase; C029684:thiobarbituric acid