Osteoblasts regulate bone formation and remodeling, and are main target cells of oxidative stress in the
progression of osteonecrosis. The stem cell factor (SCF)-c-Kit pathway plays important roles in the
proliferation, differentiation and survival in a range of cell types, but little is known about its functions
in osteoblasts. In this study, we found that c-Kit is functionally expressed in both osteoblastic-like
MC3T3-E1 cells and primary murine osteoblasts. Its ligand SCF exerted significant cyto-protective effects
against hydrogen peroxide (H2O2). SCF activated its receptor c-Kit in osteoblasts, which was required for
its cyto-protective effects against H2O2. Pharmacological inhibition (by Imatinib and Dasatinib) or
shRNA-mediated knockdown of c-Kit thus inhibited SCF-mediated osteoblast protection. Further investigations
showed that protection by SCF against H2O2 was mediated via activation of c-Kit-dependent
Akt pathway. Inhibition of Akt activation, through pharmacological or genetic means, suppressed
SCF-mediated anti-H2O2 activity in osteoblasts. In summary, we have identified a new SCF-c-Kit-Akt
physiologic pathway that protects osteoblasts from H2O2-induced damages, and might minimize the risk
of osteonecrosis caused by oxidative stress.