IN-VITRO COMPARISON OF AGED AND YOUNG OSTEOGENIC AND HEMATOPOIETIC BONE-MARROW STEM-CELLS AND THEIR DERIVATIVE COLONIES

THE PURPOSE OF THIS IN VITRO STUDY was to determine whether there were differences in the number and size of osteogenic and hemopoietic colo nies derived from bone marrow stem cells of aged and young adult male Sprague-Dawley rats. Using a Ficoll-Paque gradient, stem cells were ha rvested from aged male rats 18 to 22 months old and young adult males 55 days of age. Single cell suspensions from the red marrow of the lon g bones were cultured 14 days in vitro and subsequent colonies were as sessed by light microscopy for number and size. A computerized histomo rphometric linear measuring system was utilized to assess colony area in square millimeters. The results clearly show that young animals hav e a statistically significant increased cellular potential for osteoge nic and hemopoietic colony formation. Cultures from aged animals showe d an average formation of 0.45 +/- 0.6863 osteogenic colonies while th ose from younger animals had an average of 3.6 +/- 2.3523 osteogenic c olonies per 3 million cells plated. Hemopoietic colonies from aged ani mal cell cultures numbered 5.25 +/- 2.2449 while those from the young animals averaged 8.23 +/- 3.3601 per 3 million cells plated. The diffe rence in size of the osteogenic and hemopoietic colonies between age g roups was not statistically significant. The area of osteogenic coloni es derived from aged animals measured 0.1244 +/- 0.0891 mm(2), while t hose derived from the young animals averaged 0.1276 +/- 0.0518 mm(2). Hemopoietic colonies from the aged cells measured 0.0759 +/- 0.0514 mm (2), while hemopoietic colonies from the young animal cells measured 0 .06010 +/- 0.0180 mm(2). The results of this study may have implicatio ns for consideration in the cellular healing aspects of aged versus yo ung individuals.