Down-regulation of basic fibroblast growth factor production from cartilage by excessive mechanical stress.
BACKGROUND
We examined the effect of excessive stress on the production of basic fibroblast growth factor (bFGF) by bovine cartilage.


METHODS
Bovine articular carpal bone was harvested and cut into 1 cm thick slices horizontally. Continuous compressive stress (0, 2, 20 MPa) was loaded on the cartilage of the carpal bone using a stainless-steel cylinder with a diameter of 8 mm for 1 h. The slices were cultured immediately after compression, and the supernatant of the culture medium was collected for bFGF and nitric oxide (NO) measurement. Interleukin-4 (IL-4) or N(G)-monoethyl-L: -arginine (L: -NMEA) was added to the culture medium in some experiments.


RESULTS
Basic FGF production was significantly increased after 36 h of cultivation without mechanical stress (0.40 +/- 0.03 microg/ml). In contrast, the bFGF concentration was not increased by compressive stress of 20 MPa after 36 h of cultivation. An NO inhibitor, L: -NMEA, did not alter the effect of compressive stress on the production of bFGF. IL-4 reduced the production of bFGF by cartilage with or without mechanical stress.


CONCLUSIONS
Excessive stress on cartilage inhibits the production of bFGF in an NO-independent manner, and IL-4 plays an important role in the reduction of bFGF.
Fujiwara
Yutaka
Y
Department of Orthopaedic Surgery, Yokohama City University School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan.
Uesugi
Masaaki
M
Saito
Tomoyuki
T
D000818:Animals; D050824:Carpal Joints / Q000033:anatomy & histology / Q000378:metabolism / Q000473:pathology; D002358:Cartilage, Articular / Q000378:metabolism* / Q000473:pathology; D002417:Cattle; D015536:Down-Regulation; D004791:Enzyme Inhibitors / Q000378:metabolism; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism*; D015847:Interleukin-4 / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D013314:Stress, Mechanical; D046509:Tissue Culture Techniques; D019323:omega-N-Methylarginine / Q000378:metabolism
D004791:Enzyme Inhibitors; D016222:Fibroblast Growth Factor 2; D015847:Interleukin-4; D019323:omega-N-Methylarginine; D009569:Nitric Oxide