Enhancement of the pneumotoxic effect of cadmium acetate by ionizing radiation in the rat.

Experiments involving 120 male Wistar rats were performed to study the effect of treatment with cadmium acetate and external irradiation. A single 0.5 mg/kg body weight dose of cadmium acetate was administered intratracheally. Shortly thereafter, the animals received a single whole-body exposure to 4 Gy gamma rays (cesium source). Findings indicated the chemical elevated enzyme activities of lactate dehydrogenase (LDH), alkaline phosphatase (AlP), and acid phosphatase (AP), as well as protein content and percentage of neutrophils in bronchoalveolar lavage fluid (BALF); the percentage of alveolar macrophages was sharply reduced. Radiation alone produced no substantial changes in the parameters investigated. Treatment with both agents combined was found to result in a synergistic rise of LDH, AlP, and AP activities and protein content in BALF. It was concluded that the BALF biochemical markers used are reliable indicators for identifying the type of combined effect produced in the lungs by chemical agents and ionizing radiation.