effect of osteogenic medium on the adhesion of rat bone marrow stromal cell to the hydroxyapatite

To investigate the adhesive properties of bone marrow stromal cell [BMSC] on the hydroxyapatite [HA] particles and analyze their behavior. The study took place in the Department of the Histology and Embryology, Celal Bayar University, Manisa and in the Department of Bioengineering, Ege University, Izmir, Turkey between 2004 and 2005. We cultured BMSC from the mature rat tibia and differentiated to the osteoblasts by osteogenic medium. The BMSCs were subcultured and were taken to the HA substrate. We measured their proliferation capacity and viability with MTT assay using the spectrophotometric method. Furthermore, we identified the osteoblast-like cells by immunohistochemical staining of osteonectin and osteocalcin and we analyzed the behavior of the cells on different sized HA particles by SEM at the end of 3 days incubation. Osteogenic medium caused the proliferation capacity of BMSC to speed up and the effects appeared earlier. We confirmed the osteoblastic differentiation by staining of most cells with osteoblastic markers. Subcultured cells were similarly adhesive to the HA particles and the osteogenic medium did not alter this behavior. They spread on the substrate similarly. Most of the cells demonstrated the cytoplasmic protrusion. Morphology of the cells did not change much with or without osteogenic medium. Different sizes of HA particles did not affect the adhesive properties of these cells except HA gel. The spreading and attachment ratios of the cells on HA gel were more than the others. We found that there was heterogeneity in BMSC on differentiation capacity to the osteoblast, which was a sign of a subpopulation. Adhesive cells showed similar morphology and behavior under the effect of osteogenic medium. The only difference was the spreading capacity on the HA gel where cell used this substrate more effectively for adhesion

Cell division and cellular morphology of the chick retinal pigmented epithelial cells in culture: a time-lapse analysis

To investigate the patterns of cell division, movement and shape during early stages of development of the chick embryo retinal pigmented epithelial [RPE] cells and to evaluate the morphology of dissociated embryonic cells with regard to their proliferation capacity. We conducted this study at the Department of Histology and Embryology, Celal Bayar University, Manisa, Turkey, between 2002 and 2003. We isolated the cells from chick embryos. We analyzed the images of the embryonic cells originated from neuroepithelia using a computer-based time-lapse acquisition system attached to a differential interference contrast microscope. Retinal pigmented epithelial cells, despite being dissociated, depict a colony-type growth. Cells in the periphery of the colony and those outside the colony showed a tendency to proliferate and migrate and retained contact with the neighboring cells during division. Characteristics of cytokinesis were separation from the neighboring cell while retaining an attachment point, became rounded, moved up and started to shake and ascend to disseminate to the substrate to complete the division. The round-up stage was non-significantly shorter when the cell was closer to the center of the colony. Cells that were in the periphery of, or outside the colony had a round-up time of over one hour while cytokinesis-to-adhesion time was around 5 minutes. However, when we found the cells in the center of the colony, the times were half-an-hour and 1.5 hours for the daughter cells, a 2-fold difference between daughter cells with regard to the duration of attachment. Cell division, migration and proliferation are complex procedures influenced by growth factors, cell adhesion, matrix molecules underneath and the signal mechanisms and can be studied in detail using time-lapse microscopy, immunohistochemistry and confocal microscopy