Trypan blue 0.6 percent

Typically, the integrity of the cell membrane is evaluated by identifying the percentage of cells taking up a vital dye termed trypan blue. Cells that take up trypan blue have defective cell membranes and therefore external loading or contact with materials that cause cells to have faulty membranes are likely to cause cell injury and death. Cell cytotoxicity is evaluated by contacting a surface of a material or the extract of a material or implant with cells in culture. If more than five percent of the cell population stains with dye after contact with the material or an extract then it is considered cytotoxic. 

The toxicity is evaluated by trypan blue exclusion method. The percent toxicity... 

It is well documented that normal human bronchial epithelial cells release a variety of cytokines and chemokines, and proinflammatory cytokines such as IL-la, IL-1 3, and TNF-a stimulate their production in vitro (Fig. 11) [61], We cultured human normal and transformed bronchial epithelial cells, and studied the effect of EM, CAM, and RXM on IL-6 [17], IL-8 [60, 62] and GM-CSF [63] production. Among the antimicrobes tested, only 14-membered-ring macrolides EM, CAM, and RXM showed an inhibitory action on cytokine release by unstimulated and cytokine-stimulated human bronchial epithelial cells (Fig. 12). In contrast, a 16-membered ring macrolide josamycin (JM) failed to show such effects. LDH release assay, a trypan blue dye exclusion test, and a colorimetric MTT assay showed that this effect was not due to cytotoxicity. Percent inhibition of IL-8 protein release in human primary bronchial epithelial cells was 25.0 5.67% at lO M, which is comparable with clinically observed serum concentration. 

Figure 12-12. Percent of dead cells (cells that take up Trypan blue) after treatment at different liquid depths. The thickness of the cell layer at the bottom of the dish is about 30 pm.

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