Investigation of primary cell-biomaterial interactions using silver nitrate staining of nucleolar organising regions

The quantification of silver nitrate staining of nucleolar organising regio ns (AgNORs) within the nucleus of the cell has been shown to give a relativ e measure of the metabolic activity of the cell. In the present study, silv er nitrate staining was utilised to identify metabolic variations in cells cultured on different surfaces and compared with proliferative activity ass essed using bromodeoxyuridine (BrdU) uptake. Primary osteoblast and periost eal cells, isolated from the calvaria of neonate rats, were cultured on tis sue culture-grade (TCPS) and bacteriological-grade (BACPS) polystyrene petr i dishes for 3, 5, 7 and 9 days (silver nitrate) or 14 days (BrdU). The phe notype of the cells was examined using RT-PCR of the mRNA for osteocalcin, collagen la, alkaline phosphatase and osteopontin. The number and area of A gNORs and the proportion of BrdU positive cells were statistically differen t in cells cultured on TCPS compared with BACPS at each culture period test ed. The results suggest that the metabolic activity and proliferation of ce lls were affected by the substrate which they colonise. (C) 2001 Elsevier S cience Ltd. All rights reserved.