Zinc-related actions of sublethal levels of benzalkonium chloride: Potentiation of benzalkonium cytotoxicity by zinc.

Benzalkonium chloride (BZK) is a common preservative used in pharmaceutical and personal care products. ZnCl was recently reported to significantly potentiate the cytotoxicity of some biocidal compounds. In the present study, therefore, we compared the cytotoxic potency of BZK and then further studied the Zn-related actions of the most cytotoxic agent among BZK, using flow cytometric techniques with appropriate fluorescent probes in rat thymocytes.

Zinc increases vulnerability of rat thymic lymphocytes to arachidonic acid under in vitro conditions.

Previous studies on the cytotoxicity of arachidonic acid (ARA) elucidated the involvement of oxidative stress and Ca(2+). In the present study, the Zn(2+)-related cytotoxicity of ARA was studied by a flow cytometric technique with appropriate fluorescent probes in rat thymocytes. Addition of 10 μM ZnCl2 enhanced the increase in cell lethality induced by 10 μM ARA.