Chemico-Biological Interactions 146 (2003) 191–200 Effect of halothane on lung carcinoma cells A 549 Ralitza Valtcheva a , Elena Stephanova a,∗ , Albena Jordanova b , Roumen Pankov c , George Altankov b , Zdravko Lalchev a a Department of Cell biology, Faculty of Biology, Sofia University, St. Kliment Ohridski, 8 Dragan Tsankov blv, 1164 Sofia, Bulgaria b Institute of Biophysics, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria c Craniofacial Developmental Biology and Regeneration Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Department of Health and Human Services, Bethesda, MD 20892-4370, USA Received 1 May 2003; received in revised form 21 August 2003; accepted 21 August 2003 Abstract The halogenated hydrocarbons, such as halothane, are widely used as anesthetics in clinical practice; however their application is often accompanied with metabolic, cardiovascular and respiratory complications. One of the possible factors for this negative outcome might be the severe toxicity of these agents. In this paper, we investigate in vitro effects of halothane on human lung carcinoma A 549 cells, namely on their cytotoxicity, adhesive properties and metabolic activity. The cytotoxicity response of lung carcinoma A 549 cells to halothane was determined by lactate dehydrogenase (LDH) assay (for cytotoxicity), by detachment assay after adhesion to type IV collagen (for cell adhesive properties) and by surface tension measurements of culture medium (for cell metabolic activity). Regarding the cytotoxicity, the determined maximal non-toxic concentration of halothane on A549 cells, given here as volume percentages (vol.%) was 0.7 vol.% expressed as aqueous concentration in the culture medium. Direct measurement of the actual halothane concentration in the culture medium showed that 0.7 vol.% corresponds to 1.05 mM and 5.25 aqueous-phase minimum alveolar concentration (MAC). Concentrations equal or higher than 1.4 vol.% (2.1 mM; 10.5 MAC) of halothane provoked complete detachment (cell death), or reduction of initial adhesion to collagen IV in half of the cell population. Surfactant production of A 549 cells, registered up to 48 h after halothane treatment, was inhibited by halothane concentrations as low as 0.6 vol.% (0.9 mM; 4.5 MAC). Our results demonstrate that sub toxic halothane concentrations of 0.6 vol.% inhibits surfactant production; concentrations in the range 0.8–1.4 vol.% induce membrane damages and concentrations equal and higher than 1.4 vol.%—cell death of approxi- mately 50% of the cells. © 2003 Elsevier Ireland Ltd. All rights reserved. Keywords: Halothane; Cytotoxicity; A 549; Pulmonary surfactant ∗ Corresponding author. Tel.: +359-2-6330-213; fax: +359-2-865-66-41. E-mail address: stephanova@biofac.uni-sofia.bg (E. Stephanova). 1. Introduction The halogenated hydrocarbons, such as halothane, sevoflurane, enflurane and desflurane are widely used as anesthetics in clinical practice. The perioperative period, especially in the case of long-durable surgery 0009-2797/$ – see front matter © 2003 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.cbi.2003.08.002