Cell viability of NCM-exposed fibroblasts. Different amounts of NCM were incubated with fibroblasts for 16 h in the cell culture conditions. Loss of cell membrane integrity was evaluated by trypan blue exclusion assay. Unstained (live) and stained (dead) cells were counted and cell viability was expressed as percentage of total number of cells. (a) statistically differs from control, . Cell viability was reduced in the incubation of fibroblasts with NCM, in a concentration-dependent manner, in comparison to untreated cells (Control).