Triphenyltin disrupts intracellular Zn2+ homeostasis in rat thymic lymphocytes.

Triphenyltin (TPT), previously used as an agricultural fungicide and industrial antifoulant, is now considered an environmental pollutant. The effect of TPT on human health is concerning due to its presence as a contaminant in seafood. In this study, the changes in intracellular Zn2+ concentration ([Zn2+]i) and cellular content of nonprotein thiols ([NPT]i) induced by triphenyltin chloride (TPTCH), were measured in rat thymic lymphocytes. This was studied by flow-cytometry using the fluorescent probes FluoZin-3-AM and 5-chloromethylfluorescein diacetate (5-CMF-DA). Incubation with TPTCH, at 0.1 μM or more (up to 3 μM), increased [Zn2+]i in a concentration-dependent manner. The TPTCH-induced elevation in [Zn2+]i was due to the increase in membrane Zn2+ permeability and intracellular Zn2+ release. Incubation with TPTCH at 0.3 μM significantly increased [NPT]i levels, whereas the addition of an intracellular Zn2+ chelator had no effect on the same. TPT at higher concentrations (1 or 3 μM) reduced [NPT]i. TPT may disturb intracellular Zn2+ signaling in lymphocytes that disturbs cellular functions.