Fig. 6.

Mixture toxicity of methylisothiazolinone (MIT) and 1% propylene glycol (PG) to cultured HaCaT cells. Cultured HaCaT cells were treated with a mixture of MIT and PG for 24 hr, and viability was measured by the MTT assay. Cell viabilities did not decrease in the 1% PG-treated or negative control groups. MIT (A, 300 μM; C, 400 μM) showed cytotoxicity in a concentration-dependent manner. Its toxicity was not influenced by the 1% PG. A, 300 μM MIT; B, 300 μM MIT + 1% PG; C, 400 μM MIT; D, 400 μM MIT + 1% PG. No statistically significant (p > 0.05) difference was observed between A and B, or between C and D.