Thermotolerance induction by benzalkonium chloride in NIH3T3 cells

The ability of benzalkonium chloride to induce thermotolerance was examined in NIH3T3 cells. Benzalkonium chloride enhanced cytotoxicity as its concentration and administration period increased. The cell survival decreased to 50% of that in the non-treated group by 20min of treatment in 0.002% benzalkonium chloride. Thermotolerance developed during the culture after 20min of treatment with 0.002% benzalkonium chloride. Thermotolerance reached its peak at 15h after treatment and decreased subsequently. At 15h after treatment, the Do value at 45°C heating, a parameter of thermotolerance was 3.8-fold higher than that of the non-treated group. The thermotolerance induced by 0.002% benzalkonium chloride increased as its treatment period was prolonged. These findings suggested a relationship between thermotolerance induction and the cell membrane damage by benzalkonium chloride.