Toxicity assessment of perfluorooctane sulfonate on regenerating planarian Dugesia japonica

As a common environmental contaminant, perfluorooctane sulfonate (PFOS) can be detected in environmental media, plants, animal organs, and humans. PFOS has multiple toxic effects on neural regeneration and development in planarians, zebrafish, and other animals, but the toxic effects exerted on the maintenance of cellular homeostasis and the expression of neuron-related genes during planarian regeneration remain unclear. In this study, planarians were cut at the post-auricle level and then exposed to PFOS for different lengths of time. It was found that PFOS exposure promoted the expression of DjpiwiA, a specific marker gene of neoblasts, which was related to regeneration and the maintenance of homeostasis in planarians. High PFOS exposure inhibited the proliferation of regenerating planarian neoblasts, and there was also an effect on apoptosis in regenerating planarians after PFOS exposure. The results suggested that PFOS exposure in regenerating planarians resulted in a reduction in the density of brain ganglia and inconspicuous brain branching and altered neuronal gene expression in the nervous system. The findings of this study suggest that PFOS has multiple toxic effects on the planarian regeneration and provide a basis for uncovering the toxic effects of PFOS on stem cell proliferation, apoptosis, and the CNS.