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DEVELOPMENTAL EXPOSURE TO 1.0 OR 2.5 MG/KG DIBUTYLTIN DICHLORIDE DOES NOT IMPAIR IMMUNE FUNCTION IN SPRAGUE-DAWLEY RATS
Citation:
DEWITT, J., C. B. COPELAND, AND R. W. LUEBKE. DEVELOPMENTAL EXPOSURE TO 1.0 OR 2.5 MG/KG DIBUTYLTIN DICHLORIDE DOES NOT IMPAIR IMMUNE FUNCTION IN SPRAGUE-DAWLEY RATS. JOURNAL OF IMMUNOTOXICOLOGY. Taylor & Francis, Inc., Philadelphia, PA, 3:245-252, (2006).
Impact/Purpose:
To assess immune function in Sprague-Dawley rats after developmental dibutyltin dichloride (DBTC) exposure
Description:
Organotins are used commercially as pesticides, antifouling agents and stabilizers for polyvinyl chloride (PVC) pipe. Mono- and di-substituted methyl and butyltins, used in PVC pipe production, are of concern to the U.S. EPA as they leach from supply pipes into drinking water and have been associated with multisystem toxicity. We assessed immune function in Sprague-Dawley rats after developmental dibutyltin dichloride (DBTC) exposure. Individually housed pregnant rats were given drinking water containing 0, 10 or 25 mg/L of DBTC (final concentration) in 0.5% Alkamuls from gestational day (GD) six through weaning of the pups, for a total of 37 days. These concentrations resulted in approximate doses to dams of 1 and 2.5 mg DBTC/kg during gestation or 2.0 and 4.4 mg DBTC/kg while nursing. Litters were sexed, weighed, and culled to 4 males and 4 females per dam on postnatal day (PND) two. Beginning on PND3, litters of half of the dams per dose were gavaged with 0, 1.0, or 2.5 mg DBTC/kg body weight (BW) 3x/week for 10 doses (maternal + direct treatment); exposure of the remaining litters was indirect via lactation (maternal treatment). Body weight gain of litters from the 2.5 mg DBTC/kg group was decreased relative to other groups, but reached control group weights by PND50. Delayed-type hypersensitivity (DTH), primary and secondary antibody responses, and natural killer (NK) cell activity were evaluated in offspring after they had reached at least six weeks of age (N = 6/sex/group). DTH responses, IgM and IgG synthesis, and NK cell activity were similar among groups regardless of dose, sex, or type of exposure. Our data suggest that DBTC is unlikely to cause immunotoxicity in humans at levels found in drinking water delivered through PVC pipe as the concentrations we used were several orders of magnitude higher than concentrations expected in drinking water.