The effect of globin scaffold on osteoblast adhesion and phenotype expression in vitro. 
Different synthetic and natural biomaterials have been used in bone tissue regeneration.  However, several limitations are associated with the use of synthetic as well as allogenous or xenogenous natural materials.  This study evaluated, in an in vitro model, the behavior of rat osteoblastic cells cultured on a human globin scaffold.  Rat osteoblastic cells were isolated from the calvaria of 21-day-old fetal Sprague-Dawley rats.  They were then grown in the presence of globin.  Real-time polymerase chain reaction (RT-PCR) was performed to study the expression of cyclin D1, integrin Β1, Msx2, Dlx5, Runx2, and osteocalcin on days 1, 5, and 9.  Moreover, alkaline phosphatase activity was measured on days 1, 3, 5, and 7.  Alizarin red staining was performed on day 9 to observe calcium deposition.  Cells were able to adhere, proliferate, and differentiate on globin scaffolds.  Moreover, RT-PCR showed that globin may stimulate some key genes of osteoblastic differentiation (Runx2, osteocalcin, Dlx5).  Globin had an inhibitory effect on alkaline phosphatase activity.  Calcium deposits were seen after 9 days of culture.  These results indicate that purified human globin might be a suitable scaffold for bone tissue regeneration.