Genotoxic stress response in cave-dwelling bats from Vietnam: a pilot study

As flying mammals, bats are exposed to various environmental pollutants; therefore, a comprehensive health assessment is imperative. Evaluating cytogenotoxic biomarkers within bat populations offers insights into associated environmental risks. However, significant knowledge gaps exist regarding the cytogenotoxic investigation of bats across various habitats. Monitoring micronuclei (MNs) and polychromatic erythrocytes (PCEs) has been identified as a reasonably non-invasive method for observing the genotoxic risks to bat populations. This research constitutes the initial study of insectivorous bats in subtropical Asia to evaluate the cytogenotoxic stress responses of cave-dwelling bats in a human-impacted karst region, Vietnam. The analysis focused on three key indicators: heavy metal bioaccumulation, a hallmark of exposure; MNs, an indicator of irreversible genotoxic DNA damage; and the PCE ratio, a measure of cytotoxicity. The bioaccumulation of lead and cadmium was measured in guano samples from four caves. The frequency of MNs exhibited a significant correlation with elevated levels of lead and cadmium in guano, which surpassed the threshold required to induce MN formation. The observed MN and PCE frequencies suggest genotoxic and cytotoxic stress responses in cave-dwelling insectivorous bats due to the mutagenic potential posed by the surrounding environment. This study provides baseline datasets on the cadmium and lead thresholds for MN induction and the MN profile of cave-dwelling bats in Southeast Asia. Consequently, analysis of MNs and PCEs in bat erythrocytes offers researchers a means to evaluate the health implications of environmental contamination on these vital mammals and, by extension, on the health of the ecosystems they inhabit.