Recovery of articular cartilage metabolism following thermal stress is facilitated by IGF-1 and JNK inhibitor.
BACKGROUND
The safety of intra-articular use of thermal probes is related to whether chondrocytes can tolerate exposure to high temperatures and whether cytoprotective agents may improve chondrocyte survival after thermal injury.


OBJECTIVE
This study was conducted to characterize the metabolic responses of articular cartilage after short-term exposure to temperatures between 50 degrees C and 60 degrees C with and without addition of insulin-like growth factor 1 (IGF-1) and c-Jun N-terminal kinase (JNK) inhibitor.


METHODS
Human articular cartilage from osteoarthritic knees was subjected to defined thermal stress.


RESULTS
Although significant reduction of proteoglycan synthesis was observed after 5 seconds of exposure to 55 degrees C and 60 degrees C and after 10- to 30-second exposures to 53 degrees C, recovery of metabolic activity levels was observed after 7 days.


CONCLUSIONS
Addition of IGF-1 and JNK inhibitor Sp600125 enabled the cartilage to maintain significantly higher levels of proteoglycan synthesis immediately after thermal stress. IGF-1 also enhanced recovery of metabolic activity after 7 days.


CONCLUSIONS
Results from this study indicate that there may be time and temperature parameters within which thermal chondroplasty can be safely performed. The data additionally suggest that inadvertent chondrocyte injury may be minimized through potential addition of substances like IGF-1 or JNK inhibitor.
Chu
Constance R
CR
Department of Orthopedic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania 15232, USA.
Kaplan
Lee D
LD
Fu
Freddie H
FH
Crossett
Lawrence S
LS
Studer
Rebecca K
RK
D002358:Cartilage, Articular / Q000378:metabolism*; D019902:Chondrocytes / Q000378:metabolism*; D006801:Humans; D006979:Hyperthermia, Induced; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors*; D011509:Proteoglycans / Q000096:biosynthesis*
D011509:Proteoglycans; D007334:Insulin-Like Growth Factor I; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases