Proceedings of The Physiological Society

Europhysiology 2018 (London, UK) (2018) Proc Physiol Soc 41, PCB018

Poster Communications

Investigation of Glyphosate Toxicity and its Mechanisms using Zebrafish (Danio rerio) Vertebrate Animal Model

H. Gaur1, A. Bhargava1

1. Ion Channel Biology Lab, Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Telangana, India.

Human population is constantly exposed to health risks by exposure to chemicals belonging to various classes such as pesticides, pollutants and chemicals used in food industries etc. Unlimited and uncontrolled use of such pesticides can have serious consequences for human health. Glyphosate is one such chemical which is a non-selective, broad-spectrum herbicide, used to prevent the growth of weeds together with genetically-modified soy, corn, canola and cotton as well as in home gardens and parks. Few studies have reported a number of health issues that can arise as a result of chronic exposure to glyphosate as a pollutant. The overall objective of this study was to investigate the glyphosate induced pathology in zebrafish (Danio rerio) animal model including developmental abnormalities and cardiotoxicity. Our results indicate that glyphosate induced morphological and developmental abnormalities in developing zebrafish embryos. LC50 (Lethal concentration 50) was found to be approximately 66 μg/ml. To investigate cardiotoxicity, we chose heartbeat as a cardiac function assessment parameter. To assess heartbeat reliably and reproducibly, used our own developed ZebraPace (Gaur et al., 2018) method. Glyphosate-induced cardiotoxicity in zebrafish embryos as indicated by a significant decrease in the heartbeat in embryos exposed to 50 μg/ml (Roy et al., 2016) and 100 μg/ml of glyphosate for 48 and 72 hours. We attribute that to the selective downregulation of L-type calcium channel (encoded by cacna1c) accompanied by a selective upregulation of heat shock protein (encoded by hspb11) without any observed changes in ryanodine receptor (encoded by ryr2a) expression studied by the real-time qPCR assay. hspb11 has been used as a marker for changes in cytosolic calcium concentration. Therefore, we speculate that glyphosate may be inducing cardiotoxicity by changes in calcium signaling. In addition, in our experiments, glyphosate reduced the expression of nitric oxide (NO) as detected by fluorescence imaging using DAF-FM. NO is cardioprotective therefore any change in NO expression also indicates cardiotoxicity. Overall, our results indicate that glyphosate can induce cardiotoxicity and suggests caution in its continued and extended use especially when bioaccumulation of glyphosate has been reported.

Where applicable, experiments conform with Society ethical requirements