Release of TNF α in response to SiC fibres: differential effects in rodent and human primary macrophages, and in macrophage-like cell lines

Asbestos has been implicated in the pathogenesis of several lung diseases, but its mechanism of action is not fully understood. However, asbestos-induced oxidative stress and production of inflammatory cytokines may play a significant role. TNF α is an inflammatory cytokine which has a central role in inflammation and fibrosis due to its ability to stimulate fibroblasts and collagen deposition. In this study, a panel of fibres designated either pathogenic or non-pathogenic in recent animal studies, were utilized. The amount of TNF α released after a 16-hour exposure to the panel of fibres was compared in four different cell types; two primary macrophage cell types and two cell lines. TNF α release by cells exposed to the panel did not equate to pathogenicity, although the most pathogenic fibre caused three out of the four cell types tested, to produce the greatest amount of TNF α. Primary rat cells and primary human cells behaved in a similar manner as regards to TNF α production; the cell lines behaved quite differently to their primary counterparts with regards to TNF α production in this study.