Bone morphogenetic protein 2 stimulates articular cartilage proteoglycan synthesis in vivo but does not counteract interleukin-1alpha effects on proteoglycan synthesis and content.
OBJECTIVE
To study the effect of bone morphogenetic protein 2 (BMP-2) on articular cartilage proteoglycan (PG) synthesis in vivo and to investigate whether BMP-2 is able to counteract the effects of interleukin-1 (IL-1) on articular cartilage PG synthesis and content.


METHODS
BMP-2 alone or in combination with IL-1alpha was injected into murine knee joints. PG synthesis was measured by 35S-sulfate incorporation using an ex vivo method or autoradiography. Cartilage PG content was analyzed by measuring Safranin O staining intensity on histologic sections.


RESULTS
BMP-2 appeared to be a potent stimulator of articular cartilage PG synthesis in vivo. However, BMP-2 was not able to counteract the deleterious effects of IL-1alpha on articular cartilage PG synthesis and content. In addition, intraarticular injections of BMP-2 induced chondrophytes.


CONCLUSIONS
Although BMP-2 is a very potent stimulator of cartilage PG synthesis in vivo, the therapeutic applications of BMP-2 are limited due to the inability of BMP-2 to counteract the effects of IL-1 and the induction of chondrophytes.
Glansbeek
H L
HL
University Hospital Nijmegen, The Netherlands.
van Beuningen
H M
HM
Vitters
E L
EL
Morris
E A
EA
van der Kraan
P M
PM
van den Berg
W B
WB
D000818:Animals; D001345:Autoradiography; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D002358:Cartilage, Articular / Q000737:chemistry* / Q000166:cytology; D007375:Interleukin-1 / Q000037:antagonists & inhibitors*; D007719:Knee Joint / Q000033:anatomy & histology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011509:Proteoglycans / Q000096:biosynthesis*; D016212:Transforming Growth Factor beta / Q000494:pharmacology
C525719:Bmp2 protein, mouse; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D007375:Interleukin-1; D011509:Proteoglycans; D016212:Transforming Growth Factor beta