The following abstract presents results of a study conducted by a contract laboratory for the National Toxicology Program. The findings have not been peer reviewed and were not evaluated in accordance with the levels of evidence criteria established by NTP in March 2009. The findings and conclusions for this study should not be construed to represent the views of the NTP or the U.S. Government.
Trichloroethylene, an important environmental contaminant, had previously been shown to suppress immune function. Trichloroethylene was selected for study with the intent of performing an interaction study with ethanol with the immune system being the target system. Previous studies were performed by the investigators showing that trichloroethylene, administered in the drinking water to CD-mice for 120 days, suppressed selected parameters of the immune system. The purpose of this range-finding study was to select doses for use in the interaction study. In order for the study to be performed within the confines of an interaction study, the period of exposure was set at 14 days and higher doses than were previously reported were used. The route of administration was by gavage. Corn oil was selected as the vehicle because of the NTP historical control base. Toxicological parameters assessed were body weight, selected organ weights and selected hematological indicators. The two immunological assays used to assess immune status were the IgM spleen antibody-forming cell response to sheep erythrocytes and the cytotoxic T lymphocyte response.
Tricloroethylene, in doses between and including 50 and 800 mg/kg administered for 14 days, did not alter body weight or body weight gain or change the hematological parameters examined. Trichlorethylene, in doses including and between 100 and 800 mg/kg, caused a dose-related increase in liver weight but no changes in kidney, spleen or thymus weight. Tricloroethylene, in doses between and including 50 and 800 mg/kg administered for 14 days, did not affect the spleen IgM antibody-forming cell response to sheep erythrocytes. Trichlorethylene, in doses including and between 100 and 800 mg/kg, did not affect the cytotoxic T lymphocyte response.
Since the studies previously reported used emulphor as the vehicle, a range-finding study was conducted using emulphor as the vehicle and is reported in RF-TCE-14-2-PO.