The Effects of Polyvinyl Chloride Microparticles on the Apoptotic Processes in Zebrafish (Danio rerio) Embryos

Abstract

Pollution caused by plastics is seen as an increasing risk factor for aquatic ecosystems in recent years. Once they are entered to aquatic environment, plastics gradually break down into smaller fragments, and form microparticles (<5 mm in size). These particles are persistent in the environment and cause pollution for a much longer period of time considering their volume and distribution surface. However, the studies about the effects of microplastics on fish are still limited. In whole of the life stages of all metazoan animals, apoptosis is a sine qua non process of tissue homeostasis that requires a sensitive balance between cell renewal and controlled cell death. Although the effects of so many chemicals on apoptosis on zebrafish embryos were widely studied, no report was recorded on the effects of polyvinyl chloride (PVC) microparticles on controlled cell death. For that purpose, zebrafish embryos were exposed 96h to three different concentrations (3, 6, 9 ppm) of PVC microplastics. Acridine orange stain was specifically used to identify the apoptotic cells, and the whole embryos were examined by fluorescein microscopy. Apoptotic cells identified in different parts of embryos were calculated and compared. It was revealed that the effects of PVC microplastics were depended on increased concentrations. As a result, our findings have shown that apoptotic process could be affected by PVC microplastics depending increasing concentrations in zebrafish embryos.

Keywords: PVC microparticle, apoptosis, zebrafish, embryo, acridine orange