Butyl benzyl phthalate induced reproductive toxicity in the endoplasmic reticulum and oxidative stress in Brachionus plicatilis Müller, 1786

To study the adverse effects of butyl benzyl phthalate (BBP) on Brachionus plicatilis, rotifers were exposed to different BBP concentrations (0 [control], 0.001, 0.01, 0.1, and 1 mg/L). We measured the activities of the antioxidant enzymes superoxide dismutase, catalase, and reduced glutathione, which play a key role in detoxification, and the malondialdehyde content, which represents the level of lipid peroxidation. In addition, we investigated the effect of BBP on the submicroscopic structure and transcriptome of rotifer ovary cells. Our results showed that B. plicatilis exhibited a rapid oxidative stress response accompanied by a significant increase in superoxide dismutase enzyme activity. High BBP concentrations resulted in a significant decrease in malondialdehyde content, which indicated that BBP interferes with the lipid metabolism of rotifer cells. Our observations showed that the endoplasmic reticulum structure of rotifer ovary cells was severely damaged by BBP exposure. Transcriptomic data further demonstrated that oxidative stress and cellular sub-microstructural damage were associated with altered expression of functional genes related to rotifer redox regulation, biosynthetic processes, and cellular damage components. In conclusion, our study demonstrates that BBP triggers changes in antioxidant-related indicators in rotifers; this leads to activation of related genes and subsequent changes in intracellular signaling, which in turn triggers endoplasmic reticulum stress and ultimately leads to disruption of cell function and structure. These findings highlight the potential risks associated with BBP exposure and provide fundamental insights into its toxicological effects on marine invertebrates. •Reproductive toxicity of BBP to B. plicatilis was assessed.•Oxidative stress response associated with the reproductive toxic effects of BBP.•BBP exposure led to significant structural damage of ER stress in reproductive organ.•BBP altered redox, biosynthetic, and cell damage genes expression in B. plicatilis.