This research was undertaken to determine potential interactions between chemical and physical agents. Radiofrequency (RF) radiation is used in numerous workplaces. In addition to RF radiation exposure, many workers are concurrently exposed to various chemicals. The developmental toxicity of RF radiation is associated with the degree and duration of hyperthermia induced by the exposure. Previous animal research indicates that hyperthermia induced by an elevation in ambient temperature can potentiate the toxicity and teratogenicity of some chemical agents. We previously demonstrated that combined exposure to RF radiation (10 MHz) and the industrial solvent, 2-methoxyethanol (2ME), produces enhanced teratogenicity in rats. Interactions were noted at even the lowest levels of 2ME tested, but only at hyperthermic levels of RF radiation. The purpose of the present research is to determine if the synergistic effects noted for RF radiation and 2ME are generalizable to other chemicals. Since salicyclic acid (SA) is widely used as an analgesic and is teratogenic in animals, we selected SA as another chemical to address generalizability. Based on the literature and our pilot studies, 0, 250, or 350 mg/kg SA were administered on gestation day 9 or 13 to groups of 10 Sprague-Dawley rats. Concurrently, rats given SA on day 9 were exposed to RF radiation sufficient to maintain the colonic temperature at 41.0 C for 60 min (or sham). Those given SA on day 13 were also given 0 or 100 mg/kg 2ME. Dams were sacrificed on gestation day 20, and the fetuses were weighed and examined for external malformations. Preliminary results indicate that combined RF radiation and SA enhance developmental toxicity (resorptions plus malformations such as exencephaly, spina bifida, and gastroschisis). It appeared that there was no interaction between SA and 2ME on malformations (primarily shortened forepaw digits). The data suggest, therefore, that the combined exposure effects previously reported for 2ME and RF radiation are not unique to these two chemical and physical agents.
Radiation; Radiation-exposure; Toxicology; Hyperthermia; Solvents; Synergism; Laboratory-animals; Animals; Animal-studies; Radiation-exposure; Workers; Occupational-exposure; Exposure-limits; Teratogens; Teratology; Teratogenesis; Toxic-effects; Exposure-levels; Exposure-assessment; Radiation-effects