[The biological function of platelet-derived growth factor-BB in the osteoblast-osteoclast co-culture system].
OBJECTIVE
To investigate the biological effects of platelet-derived growth factor (PDGF)-BB on the osteoclasts in the osteoblast-osteoclast co-culture system.


METHODS
The human osteoblasts and osteoclasts were isolated from the iliac crest of patients and co-cultured in the same system. The PDGF-BB or PDGF-BB + NO synthase inhibitor, N(G)-monomethyl-L-arginine (L-NMMA) was administered to the co-culture system. The tartrate-resistant acid phosphatase (TRAP) activities in the medium were measured by enzyme kinetics. The resorption pits were stained by toludine blue. The area and number of the resorption pits were determined with the Leica Quantimet 500 system.


RESULTS
Under the stimuli of PDGF-BB in the co-culture system, TRAP activities changed from 1.40 U/L +/- 0.12 U/L to 1.46 U/L +/- 0.08 U/L (P > 0.05) in the medium, and the area and number of resorption pits was changed from (427 +/- 149) micrometer(2) and (13.3 +/- 0.9) per slice to (436 +/- 147) micrometer(2) and (14.1 +/- 1.2) per slice respectively (P > 0.05). After the L-NMMA was applied to the system, the TRAP activities rose significantly from 1.46 U/L +/- 0.10 U/L to 2.47 U/L +/- 0.38 U/L along with the increase of dose of PDGF-BB, and the number and area of the resorption pits increased significantly from 436 micrometer(2) +/- 147 micrometer(2) and (14.1 +/- 1.2) per slice to 592 micrometer(2) +/- 171 micrometer(2) and (22.5 +/- 1.7) per slice. Both the TRAP activities and resorption pits rose significantly after the L-NMMA was administered. Comparisons of different treatment groups were made using analysis of variance (ANOVA) with multiple comparisons and a Student-Newman-Keuls test.


CONCLUSIONS
The nitric oxide (NO) was produced by osteoblasts stimulated by PDGF-BB in the osteoblast-osteoclast co-culture system. Therefore, the direct promotion effects of PDGF-BB on the osteoclasts were inhibited.
Zhang
Z
Z
Department of Orthopaedics and Spinal Surgery, NanFang Hospital, The First Medical University of PLA Guangzhou 510515, China.
Chen
J
J
Jin
D
D
D000135:Acid Phosphatase / Q000378:metabolism; D000077214:Becaplermin; D001862:Bone Resorption / Q000517:prevention & control; D018920:Coculture Techniques; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism; D009569:Nitric Oxide / Q000502:physiology; D010006:Osteoblasts / Q000187:drug effects* / Q000502:physiology / Q000648:ultrastructure; D010010:Osteoclasts / Q000187:drug effects* / Q000502:physiology / Q000648:ultrastructure; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D020574:Proto-Oncogene Proteins c-sis; D000071681:Tartrate-Resistant Acid Phosphatase; D019323:omega-N-Methylarginine / Q000494:pharmacology
D007527:Isoenzymes; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D000077214:Becaplermin; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase