BMP‐7 and CBFA1 in allograft bone in vivo bone formation and the influence of γ‐irradiation

Abstract

An initial study showed that morselized human bone grafts were osteoconductive and osteoinductive when implanted in nude rat tibial window defects, and 25 kGy of gamma-irradiation significantly reduced those properties. The mechanism of the osteoinductivity and the influence of gamma-irradiation required further investigation. In this study we assessed the paraffin sections of seven morselized human bone grafts implanted into rat tibial defects for 3 weeks after being treated with 0, 15, or 25 kGy gamma-radiation respectively. Osteoclast-like cell counting and protein expressions of bone morphogenetic protein-7 (BMP-7), core binding factor alpha1 (CBFA1), and proliferating cell nuclear antigen (PCNA) were investigated and the positive signals were quantitatively analyzed. More new bone formation was observed in the 0 and 15 kGy groups compared with 25 kGy groups. The newly formed bones were found mainly from the intact cortex into the defects bridged by the implanted grafts. A dense staining of BMP-7 and CBFA1 was noted in the osteoblast-like cells in those areas. The BMP-7 and CBFA1 staining was also seen in the cells surrounding the implanted grafts in the centre areas of the defects in distance from the intact cortex. Quantitative analysis of immunohistochemical staining of the centre areas of the defects showed that gamma-irradiation (15 and 25 kGy) significantly reduced the expression of CBFA1 and BMP-7. In conclusion, morselized human bone grafts may contain some factors, which induced osteoblast lineage differentiation and bone formation and gamma-irradiation damages those bone inducing factors.

Radiation Therapy for Prevention of Heterotopic Ossification about the Elbow

“…The suggested radiobiological mechanism of RT consists of a suppression of the transformation of the pluripotent mesenchymal cells into osteoprogenitor cells and osteoblasts [33]. Furthermore, experimental data revealed that γ-irradiation significantly reduces the expression of BMP-7 (bone morphogenic protein-7) and CBFA1 (core binding factor alpha 1) which play a key role in the cellular process of differentiation of osteoblasts and the consecutive formation of ectopic bone tissue [7]. Considering the large number of orthopedic procedures which are possibly associated with an increased risk for the development of clinically significant HO, it is surprising that only a low number of reports have been published providing information about the value of RT in sites other than the hip joint.…”

Spatial learning and memory deficit of low level polybrominated diphenyl ethers-47 in male adult rat is modulated by intracellular glutamate receptors

“…IHC was performed as described previously (Chen et al, 2007). Eight animals were sacrificed for IHC.…”

Validation of 11 kGy as a Radiation Sterilization Dose for Frozen Bone Allografts

“…Several authors report that gamma irradiation does not directly affect BMPs, but indirectly changes their performance by attacking their courier -the collagen molecules (24)(25)(26). A dose-dependent reduction in BMP-7 and CBFA1 expression in 3-week-postimplanted allografts have also been observed using immunohistochemistry (27). In this case, the reduction was much more significant at 25 kGy than 15 and 0 kGy.…”