Down-regulation of the Wnt, estrogen receptor, insulin-like growth factor-I, and bone morphogenetic protein pathways in osteoblasts from rats with chronic spinal cord injury

ObjectivesTo investigate the anabolic response of osteoblasts to chronic spinal cord injury and to identify potential signaling pathways that are associated with the osteogenic response after spinal cord injury by using in-house microarray analyses in osteoblasts.MethodsTen young male Sprague-Dawley rats were randomized into spinal cord injury (SCI) and SHAM groups. The tibiae were assessed for DXA and bone histomorphometry, and osteoblasts from femora were used for microarray analysis.ResultsSCI rats showed lower BMD and deteriorated microstructure in the proximal tibiae as compared with SHAM rats. The Wnt, BMP/TGF, estrogen receptor (ER), and IGF-I pathways were down-regulated in osteoblasts from spinal cord-injured rats.ConclusionDown-regulation of the Wnt, BMP/TGF, ER, and growth hormone/IGF-I pathways is associated with decreased bone formation after spinal cord injury.