A COMPARISON BETWEEN CHROMIUM-51 RELEASE AND LDH RELEASE TO MEASURE CELL-MEMBRANE INTEGRITY - INTEREST FOR CYTOCOMPATIBILITY STUDIES WITH BIOMATERIALS

A variety of methods have been recorded for the assessment of altered cellular functions caused by biomaterials. Cell membrane integrity can be determined by different tests depending upon the cell membrane permeability to various markers. To measure the degree of cell damage, we have chosen to compare the release of two markers in the supernatants: enzyme lactate dehydrogenase (LDH, which we wanted to compare to that of radioactive chromium preincorporated in cells, the latter being validated by a standard), from three cell types: cells from a fibroblastic cell line (3T3 Balb/c) and human differentiated endothelial cells and osteoblasts, exposed to injurious agents and to biomaterials of classical use. The labeling procedure as well as the incubation periods performed, were carried out according to a standard. Cell labeling efficiency ranged from 4 to 10%. The biomaterials tested provoked no or slight cell membrane damage. After linear regression analysis, we found high correlation coefficients between chromium release and LDH release. Thus, the determination of LDH activity, which is easy to manipulate, could be a satisfactory test to evaluate cell membrane integrity in contact with biomaterials and a prerequisite stage before the more sophisticated chromium-51 release test. (C) 1993 John Wiley & Sons, Inc.