engleski

Combined exposure to halothane and 1 or 2 Gy ionizing radiation causes synergistic effect in DNA damage in both blood and liver of Swiss albino mice

Patient immobilization by general volatile anaesthesia (VA) during medical radiology treatment is sometimes necessary and thus far it has had quite an annual increase. With ionizing radiation exposure there will be for sure some level of DNA damage since IR is a well-known genotoxic and cytotoxic agent, although the doses used are maintained at the minimum, with good localization in order to spare as much as possible healthy tissue and organs that do not need to be exposed. Recently, there is a growing number of studies demonstrating that volatile anaesthetics can cause also DNA damage effect in patients, and in occupationally exposed personnel. Since there are no studies on IR and VA combined effects, we decided to use animal model and check whether there are elevated levels of DNA damage after combined exposure by mimicking the real conditions of exposure during the radio-treatment using animal model of Swiss albino mice. Healthy mice were anaesthetized by inhaling 2.4% halothane mixture with oxygen and air for 2 hours and then were exposed to either 1 or 2 Gy of ionizing radiation (60Co source, Theratron Phoenix teletherapy unit, Atomic Energy Ltd., in at the Clinical Hospital ʺSveti Duhʺ, 1.88Gy/min doze rate). With 5 animals per group, there were groups exposed only to halothane, only to radiation of 1 or 2 Gy and to combined exposure of halothane and 1 Gy or 2 Gy radiation, and there were groups examined immediately after exposure, 2, 6 and 24 hours after the exposure. Blood was taken from the tail immediately after the exposure, and liver after sacrifice of the animal. Study was approved by Ethical Committee of the Faculty of Science (University of Zagreb, Croatia) and was designed in accordance with the relevant Croatian guidelines: The Animal Protection Act (NN 102/17.) and the Ordinance on the protection of animals used for scientific purposes (NN 55/13 ; 39/17). Single cell samples were prepared for the alkaline comet assay, and DNA damage was assessed with the Comet Assay IV software. The results performed in duplicate slide, in total od 200 comets per each point, demonstrated that both halothane and IR demonstrated elevated levels of DNA damage, and that combined treatment caused synergistic effect that increased with the dose of radiation and was not repaired not even after 24 hours from the exposure. These data are confirming the concern about safety of combined VA and IR exposure, and calling for further investigation on the safety and proper use of the type of the anaesthetic necessary used during radiotherapy

halothane ; ionizing radiation ; Swiss albino mice ; alkaline comet assay

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