A novel apparatus for the exposure of cultured cells to volatile agents

This article presents a novel exposure apparatus that allows the exposure o f cultured cells to volatile chemicals, e.g., inhalation anesthetics. The a pparatus consists of an exposure chamber and a tightly linked vaporizer uni t with pumps and valves allowing adjustable fluxes of mixtures of test chem icals and carrier gas under open and closed-circuit conditions. The exposur e chamber uses commercially available cell culture flasks and accommodates up to 12 flasks simultaneously. Both modules fit into a standard culture in cubator. The exposure chamber may be mounted onto an oscillating axis to ti lt the cultures periodically forth and back, thus allowing direct contact o f the cells with test atmosphere. The vaporizer unit is connected to a pers onal computer which lets the experimenter set the "open" and "close" interv als of individual valves thereby controlling the composition and now rate o f the test gas mixture. The vapor concentration of test chemicals can be mo nitored at the inlet and outlet using infrared photodetectors or mass spect rometers. Computer-aided processing of exposure protocols allows unattended runs. Exposure protocols can be scripted and stored on disk, thus ensuring interexperimental reproducibility of complex exposure profiles. As an appl ication example, the effect of three volatile anesthetics, halothane, enflu rane, and isoflurane, on the viability of three commercially available cell lines (A549-human lung carcinoma, HTC-rat hepatoma, MDCK-Madin-Darby canin e kidney) was investigated. After exposure to haloalkyl vapors (3%) for 6 a nd 24 h, respectively, significantly increased LDH levels versus controls, indicating cellular membrane damage, were detected in A549 and hepatoma cel ls after exposure for 24 h. Hepatoma cells showed a significant LDH release also after 6 h exposure to isoflurane. On the other hand, LDH release from MDCK cells was not significantly different from controls even after 24 h o f continuous exposure to any of the tested anesthetics. (C) 1999 Elsevier S cience Inc.