Volatile anaesthetic halothane causes DNA damage in A549 lung cells

Effect of Inhalation Anesthetics on Tumor Metastasis

Many factors affect the prognosis of patients undergoing tumor surgery, and anesthesia is one of the potential influencing factors. In general anesthesia, inhalation anesthesia is widely used in the clinic because of its strong curative effect and high controllability. However, the effect of inhalation anesthetics on the tumor is still controversial. More and more research has proved that inhalation anesthetics can intervene in local recurrence and distant metastasis of tumor by acting on tumor biological behavior, immune response, and gene regulation. In this paper, we reviewed the research progress of diverse inhalation anesthetics promoting or inhibiting cancer in the critical events of tumor recurrence and metastasis, and compared the effects of inhalation anesthetics on patients' prognosis in clinical studies, to provide theoretical reference for anesthesia management of patients undergoing tumor surgery.

The common anesthetic, sevoflurane, induces apoptosis in A549 lung alveolar epithelial cells

Lung alveolar epithelial cells are the first barrier exposed to volatile anesthetics, such as sevoflurane, prior to reaching the targeted neuronal cells. Previously, the effects of volatile anesthetics on lung surfactant were studied primarily with physicochemical models and there has been little experimental data from cell cultures. Therefore it was investigated whether sevoflurane induces apoptosis of A549 lung epithelial cells. A549 cells were exposed to sevoflurane via a calibrated vaporizer with a 2 l/min flow in a gas‑tight chamber at 37˚C. The concentration of sevoflurane in Dulbecco's modified Eagle's medium was detected with gas chromatography. Untreated cells and cells treated with 2 µM daunorubicin hydrochloride (DRB) were used as negative and positive controls, respectively. Apoptosis factors, including the level of ATP, apoptotic‑bodies by terminal deoxynucleotidyl transferase‑mediated dUTP nick end labeling (TUNEL) assay, DNA damage and the level of caspase 3/7 were analyzed. Cells treated with sevoflurane showed a significant reduction in ATP compared with untreated cells. Effects in the DRB group were greater than in the sevoflurane group. The difference of TUNEL staining between the sevoflurane and untreated groups was statistically significant. DNA degradation was observed in the sevoflurane and DRB groups, however this was not observed in the untreated group. The sevoflurane and DRB groups induced increased caspase 3/7 activation compared with untreated cells. These results suggest that sevoflurane induces apoptosis in A549 cells. In conclusion, 5% sevoflurane induced apoptosis of A549 lung alveolar epithelial cells, which resulted in decreased cell viability, increased apoptotic bodies, impaired DNA integrality and increased levels of caspase 3/7.

An alternative gas-phase in vitro exposure system for toxicity testing: the interaction between nitrous oxide and A549 cells

An original in vitro approach was adopted to expose cells to volatile agents. The anaesthetic nitrous oxide (N(2)O) was chosen as the model agent, and type II pneumocyte-like cells (A549 cells) were used as the target to represent the lungs. A time-lapse microscopy station was equipped with a manual gas mixer that allowed the generation of a mixture of N(2)O/air/CO(2) in the gas phase, to provide a uniform distribution of the volatile agent. The dissolution of N(2)O in the culture medium was monitored by gas chromatography-electron capture detection. Biochemical alterations, in terms of homocysteine accumulation, demonstrated that intracellular methionine synthase had been inactivated by N(2)O absorbed by the cells, a process that also occurs in vivo. Toll-like receptors, which are key molecules in inflammatory lung diseases, were also investigated at the molecular level. Our experiments indicated that biochemical and molecular alterations occurred in the cells, even under conditions where neither morphologic changes nor consistent alterations in cell proliferation were evident. This in vitro exposure system can be efficiently adopted for looking at the repeat-dose effects of volatile agents on respiratory tissues. Moreover, it could be of further benefit for identifying the wide range of specific cell targets, and for monitoring relevant endpoints in the cellular and molecular processes that occur during exposure to volatile compounds.

The in vivo genotoxicity of cisplatin, isoflurane and halothane evaluated by alkaline comet assay in Swiss albino mice

The aim of this study was to evaluate the genotoxicity of repeated exposure to isoflurane or halothane and compare it with the genotoxicity of repeated exposure to cisplatin. We also determined the genotoxicity of combined treatment with inhalation anaesthetics and cisplatin on peripheral blood leucocytes (PBL), brain, liver and kidney cells of mice. The mice were divided into six groups as follows: control, cisplatin, isoflurane, cisplatin-isoflurane, halothane and cisplatin-halothane, and were exposed respectively for three consecutive days. The mice were treated with cisplatin or exposed to inhalation anaesthetic; the combined groups were exposed to inhalation anaesthetic after treatment with cisplatin. The alkaline comet assay was performed. All drugs had a strong genotoxicity (P<0.05 vs. control group) in all of the observed cells. Isoflurane caused stronger DNA damage on the PBL and kidney cells, in contrast to halothane, which had stronger genotoxicity on brain and liver cells. The combination of cisplatin and isoflurane induced lower genotoxicity on PBL than isoflurane alone (P<0.05). Halothane had the strongest effect on brain cells, but in the combined treatment with cisplatin, the effect decreased to the level of cisplatin alone. Halothane also induced the strongest DNA damage of the liver cells, while the combination with cisplatin increased its genotoxicity even more. The genotoxicity of cisplatin and isoflurane on kidney cells were nearly at the same level, but halothane caused a significantly lower effect. The combinations of inhalation anaesthetics with cisplatin had stronger effects on kidney cells than inhalation anaesthetics alone. The observed drugs and their combinations induced strong genotoxicity on all of the mentioned cells.

Mitochondria are involved in stress response of A549 alveolar cells to halothane toxicity

During inhalation anaesthesia lung epithelial cells are directly exposed to halogenated hydrocarbons such as halothane. Information about the effects of volatile anaesthetics on lung cells is rather limited although their noxious effect on the A549 alveolar cells has been shown recently. The present study indicated that halothane decreases cell viability, impairs DNA integrity and provokes stress-induced apoptosis in A549 cells when applied at clinically relevant concentrations. Data obtained clearly demonstrated intensive expression of anti-apoptotic Bcl-2 protein during treatment with all tested concentrations. In post-treatment periods the increased DNA injury was accompanied by reduction of Bcl-2 expression. We concluded that the in vitro effect of halothane on lung cells involved alteration in the expression of proteins of the mitochondrial apoptotic pathway.