Interactions of Osteoblastic and Other Cells with Bioactive Glasses and Silica In Vitro and In Vivo

✍ Scribed by I. A. Silver; M. Erecinska

• Publisher: John Wiley and Sons
• Year: 2003
• Tongue: English
• Weight: 116 KB
• Volume: 34
• Category: Article
• ISSN: 0933-5137
• DOI: 10.1002/mawe.200300710

✦ Synopsis

Abstract

Responses of cells to the presence of 90‐150 μm particles of 3 bioactive glasses were compared with their reaction to non‐bioactive borosilicate glass and to a known tissue irritant, quartz/silica. Measurements were made in vitro and in vivo of changes of intra‐ and extracellular ion activities. Ion‐selective microelectrodes were used to determine intracellular pH, [Na^+^], [K^+^] and [Ca^2+^] in cultured rodent osteoblasts, fibroblasts and macrophages in contact with, or exposed to medium containing, Bioglass® 45S5, borosilicate glass and bioactive glasses 77S and 58S. The same materials were implanted in connective tissue in rabbit ear chambers and similar measurements were made in vivo. No significant differences were observed among the 3 cell‐types in their reactions, which were minimal, to the presence of the borosilicate and 58S and 77S glasses either in vivo or in vitro. However all cells were affected by interaction with Bioglass® 45S5 which caused significant alkalinisation at its extracellular contact sites and concomitant but smaller changes in internal pH. The latter were accompanied by significant increases in [K^+^], [Na^+^] and [Ca^2+^]. There was also hyperpolarisation of plasma membrane potential in fibroblasts and osteoblasts. In the presence of silica, macrophages showed marked and significant decreases in pH both at the contact zone and intracellularly. Among the cells used, osteoblasts showed higher and macrophages lower pH than fibroblasts when in contact with the test materials. Despite the known leaching of silicic acid from Bioglass® macrophages were not “activated” by its presence, but were by silica. It is concluded that materials developed as potential prostheses should also be examined for their ability to alter cellular metabolism.