August 1, 2012.
The health of skeletal tissue is dependent, in part, on a balanced coexistence between two main cell types: osteoblasts, which form the mineralized structure of bone, and osteoclasts, which digest and break down bone. Communication between these two cell types is facilitated by osteoblast production of receptor activator of nuclear factor kappa‐B (RANK) ligand and osteoprotegerin (OPG). The increased bone loss anticipated after long‐term spaceflight may be associated with the degenerative effects of ionizing radiation on this system. We hypothesize that ionizing radiation associated with spaceflight modulates RANK‐Ligand/OPG expression in osteoblasts, consequently altering the behavior of osteoclasts. To examine the effects of irradiation on mRNA levels of RANK‐Ligand/OPG, and subsequent effects on osteoclasts, we irradiate MC3T3‐E1 cells (osteoblast cell line) with 2Gy of ionizing radiation and introduce RAW 246.7 cells (osteoclast cell line) to the culture 1 day after. Q‐PCR is performed for RANK‐Ligand and OPG gene expression at multiple time points to assess for changes in RANK‐Ligand/OPG ratio. Calcium phosphate resorption plates as well as TRAP staining are used to assess osteoclast levels of differentiation and bone resorption. These results increase our understanding of the implications of ionizing irradiation for human bone health, further preparing us for long‐term spaceflight.
NASA Ames Research Center (ARC)
This material is based upon work supported by the S.D. Bechtel, Jr. Foundation and by the National Science Foundation under Grant No. 0952013. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the S.D. Bechtel, Jr. Foundation or the National Science Foundation. This project has also been made possible with support of the National Marine Sanctuary Foundation. The STAR program is administered by the Cal Poly Center for Excellence in Science and Mathematics Education (CESaME) on behalf of the California State University (CSU).