Genomic instability induced by a-pinene in Chinese hamster cell line

Abstract

Here, we report the effects of exposure of mammalian cells to a-pinene, a bicyclic monoterpene used in insecticides, solvents and perfums. Morphological analysis, performed in V79-Cl3 cells exposed for 1 h to increasing concentrations (25 up to 50 mM) of a-pinene, indicated a statistically significant increase in micronucleated and multinucleated cell frequencies; apoptotic cells were seen at 40 and 50 mM. This monoterpene caused genomic instability by interfering with mitotic process; in fact, 50% of cells (versus 19% of control cells) showed irregular mitosis with multipolar or incorrectly localised spindles. Cytogenetic analysis demonstrated high-frequency hypodiploid metaphases as well as endoreduplicated cells and chromosome breaks. Clastogenic damage was prevalent over aneuploidogenic damage as demonstred by the higher proportion of kinetochore-negative micronuclei. Alkaline comet confirmed that monoterpene exposure caused DNA lesions in a concentration-dependent manner. This damage probably arose by increased reactive oxygen species (ROS) production. In order to assess the generation of ROS, the cells were incubated with CM-H2DCFDA and then analysed by flow cytometry. Results demonstrated an increase in fluorescence intensity after a-pinene treatment indicating increased oxidative stress. On the whole, these findings strongly suggest that a-pinene is able to compromise genome stability preferentially through mitotic alterations and to damage DNA through ROS production.