Bone is a connective tissue constituted of osteoblasts, osteocytes, and osteoclasts and a mineralized extracellular matrix, which gives it its strength and flexibility and allows it to fulfill its functions. Bone is continuously exposed to a variety of stimuli, which in pathological conditions can deregulate bone remodeling. To study bone biology and diseases and evaluate potential therapeutic agents, it has been necessary to develop in vitro and in vivo models. This manuscript describes the dissection process and culture conditions of calvarias isolated from neonatal mice to study bone formation and the bone tumor microenvironment. In contrast to in vitro and in vivo models, this ex vivo model allows preservation of the three-dimensional environment of the tissue as well as the cellular diversity of the bone while culturing under defined conditions to simulate the desired microenvironment. Therefore, it is possible to investigate bone remodeling and its mechanisms, as well as the interactions with other cell types, such as the interactions between cancer cells and bone. The assays reported here use calvarias from 5-7 day old BALB/C mice. The hemi-calvarias obtained are cultured in the presence of insulin, breast cancer cells (MDA-MB-231), or conditioned medium from breast cancer cell cultures. After analysis, it was established that insulin induced new bone formation, while cancer cells and their conditioned medium induced bone resorption. The calvarial model has been successfully used in basic and applied research to study bone development and cancer-induced bone diseases. Overall, it is an excellent option for an easy, informative, and low-cost assay.
In vitro mimics of bone remodeling and the vicious cycle of cancer in bone.J Cell Physiol. 2014 Apr;229(4):453-62. doi: 10.1002/jcp.24464. J Cell Physiol. 2014. PMID: 24022654
Novel bioactivity of phosvitin in connective tissue and bone organogenesis revealed by live calvarial bone organ culture models.Dev Biol. 2013 Sep 1;381(1):256-75. doi: 10.1016/j.ydbio.2013.06.005. Epub 2013 Jun 18. Dev Biol. 2013. PMID: 23791550
Selective tyrosine kinase inhibition of insulin-like growth factor-1 receptor inhibits human and mouse breast cancer-induced bone cell activity, bone remodeling, and osteolysis.J Bone Miner Res. 2013 May;28(5):1229-42. doi: 10.1002/jbmr.1847. J Bone Miner Res. 2013. PMID: 23239200
Co-culture systems of osteoblasts and osteoclasts: Simulating in vitro bone remodeling in regenerative approaches.Acta Biomater. 2020 May;108:22-45. doi: 10.1016/j.actbio.2020.03.043. Epub 2020 Apr 3. Acta Biomater. 2020. PMID: 32251782 Review.
Ex Vivo Organ Cultures as Models to Study Bone Biology.JBMR Plus. 2020 Feb 14;4(3):10.1002/jbm4.10345. doi: 10.1002/jbm4.10345. eCollection 2020 Mar. JBMR Plus. 2020. PMID: 32161838 Free PMC article. Review.