Assay of SF sub 6 and Spark-Decomposed SF sub 6 for Mutagenic Activity in the CHO/HGPRT (Chinese Hamster Ovary/Hypoxanthine-Guanine Phosphoribosyl Transferase) Mammalian Cell System

摘要

The potential mutagenic (and cytotoxic) activity of SF sub 6 and spark-decomposed SF sub 6 was investigated in an in vitro mammalian cell culture system using Chinese Hamster Ovary (CHO) cells. The CHO cells were exposed to the gases in vacutainer tubes which were constantly rotated. After a 4 h exposure the mutagenic and cytotoxic activity was assayed with the CHO/hypoxanthine-guanine phosphoribosyl transferase (CHO/HGPRT) system. Results indicated that SF sub 6 was neither cytotoxic nor mutagenic to CHO cells. Spark-decomposed SF sub 6 was found to be strongly cytotoxic (-80% cell death following 4 h exposure to 2 kJ spark discharge in 60 cm sup 3 at 1000 torr of SF sub 6 ) but not mutagenic. Increasing spark energy increased cytotoxicity but the spark samples remained nonmutagenic. The CHO/HGPRT system was coupled with a metabolic activation (S9 fraction) system used for detecting promutagens. When exposures were carried out in the presence of S9 fraction, SF sub 6 was still neither cytotoxic nor mutagenic; spark-decomposed SF sub 6 was again strongly cytotoxic but not mutagenic. It appears that SF sub 6 and sparked SF sub 6 are neither promutagens nor direct acting mutagens in the CHO/HGPRT system. Studies have begun using a more mutagenically sensitive subclone of the CHO cells known as CHO-AS sub 52 . The results of initial experiments using the CHO-AS sub 52 cells remain unchanged. 9 refs., 1 tab. (ERA citation 12:025962)