Preventing friction-induced chondrocyte apoptosis: comparison of human synovial fluid and hylan G-F 20.
OBJECTIVE
Symptomatic osteoarthritis (OA) is a common painful disease with limited treatment options. A rising number of patients with OA have been treated with intraarticular injections of hyaluronic acid, including the high-molecular-weight hylan G-F 20, which is injected following arthrocentesis. We investigated the effectiveness of hylan G-F 20 to lower coefficient of friction (COF) and prevent chondrocyte apoptosis in vitro.


METHODS
A disc-on-disc bovine cartilage bearing was used to measure the static and kinetic COF when lubricated with hylan G-F 20, human synovial fluid (HSF), and phosphate buffered saline (PBS). Following friction testing, we stained paraffin-embedded sections of these cartilage bearings for activated caspase-3, a marker of apoptosis.


RESULTS
Bearings lubricated with hylan G-F 20 had kinetic COF values that were similar to bearings lubricated with PBS, but significantly higher than those lubricated with HSF. There were no significant differences in static COF values in bearings lubricated with hylan G-F 20 as compared to PBS or HSF. However, bearings lubricated with HSF had significantly lower static COF values compared to bearings lubricated with PBS. The mean percentage of caspase-3-positive chondrocytes in the superficial and upper intermediate zones of bearings lubricated with hylan G-F 20 was significantly higher compared to that of bearings lubricated with HSF or unloaded controls, but significantly lower than in those lubricated with PBS.


CONCLUSIONS
These findings indicate that joint lubrication may prevent chondrocyte apoptosis by lowering the COF. Further, removal of synovial fluid prior to hylan G-F 20 injection may be detrimental to cartilage health.
Department of Orthopedics, and Department of Emergency Medicine, Warren Alpert Medical School of Brown University/Rhode Island Hospital, Providence, Rhode Island 02903, USA.
Kimberly A
KA
Waller
Ling X
LX
Zhang
Braden C
BC
Fleming
Gregory D
GD
Jay
D000328:Adult; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001672:Biocompatible Materials / Q000494:pharmacology*; D053148:Caspase 3 / Q000032:analysis; D002417:Cattle; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology / Q000187:drug effects*; D019610:Cytoprotection; D017276:Friction; D006801:Humans; D006820:Hyaluronic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D054327:Lubricants / Q000494:pharmacology*; D008297:Male; D013582:Synovial Fluid / Q000502:physiology*
D001672:Biocompatible Materials; D054327:Lubricants; C049816:hylan; D006820:Hyaluronic Acid; C505407:CASP3 protein, human; D053148:Caspase 3