Abstract: Objective To investigate the effect of recombinant adenovirus-mediated bone morphogenetic protein (BMP)-2 and -3
overexpressions on chondrogenesis and osteogenesis of prenatal mouse intervertabral disc cells and provide experimental
evidences for the application of BMPs in the therapy of disc diseases. Methods The prenatal mouse intervertabral disc cells
were infected with a recombinant adenovirus expressing BMP-2 and BMP-3 for 5-7 days, and the expressions of collagen type I
(Col I), collagen type II (Col II), aggrecan, osteocalcin, osteoprotegerin and osteopontin mRNAs were detected with RT-PCR.
The expression of cartilage matrix was evaluated with toluidine blue staining, and alkaline phosphatase (ALP) activity was
detected with ALP reading and ALP staining. Results BMP-2 and -3 overexpression did not enhance chondrogenesis and
osteogenesis of annulus fibrosus (AF) cells or cause significant increases in the expressions of Col I, Col II or aggrecan mRNA in
nucleus pulposus (NP) cells. Adenovirus-mediated overexpression of BMP-2 and BMP-3, however, promoted osteogenesis of
NP cells and significantly increased the expression of osteocalcin mRNA; the overexpression of BMP-2, but not BMP-3,
enhanced the mRNA expressions of osteoprotegerin and osteopontin. Toluidine blue staining demonstrated that BMP-2 and
BMP-3 overexpression did not obviously affect the secretion of cartilage matrix. In NP cells, BMP-2 and -3 overexpression
significantly enhanced ALP activity, which was not observed in AF cells. Conclusion Adenovirus-mediated BMP-2 and -3
overexpression can promote the osteogenic differentiation of NP cells but can not affect osteogenesis of AF cells or
chondrogenesis of NP cells.