Inhibition of IL-1β release from long CNT-treated macrophages. (A) Example images of macrophages treated with NTlong2 with or without cytochalasin D. Cytochalasin D inhibits the attempted uptake of long fibres by the macrophages. (B) Cytochalasin D caused a dose-dependent inhibition of IL-1β release from macrophages treated with NTlong1 and NTlong2 but not LPS. Significance versus 0 μM cytochalasin D within each treatment group *** indicates p < 0.001. A loss of cell viability in the presence of cytochalasin D was not detected by LDH release. Data expressed as mean ± sem, n = 3.