Quantification of computational fluid dynamics simulation assists the evaluation of protection by Gypenosides in a zebrafish pain model

In recent years, due to its rapid reproduction rate and the similarity of its genetic structure to that of human, the zebrafish has been widely used as a pain model to study chemical influences on behavior. Swimming behaviors are mediated by motoneurons in the spinal cord that drive muscle contractions, therefore a knowledge of internal muscle mechanics can assist the understanding of the effects of drugs on swimming activity. To demonstrate that the technique used in our study can supplement biological observations by quantifying the contribution of muscle effects to altered swimming behaviours, we have evaluated the pain/damage caused by 0.1% acetic acid to the muscle of 5 dpf zebrafish larvae and the effect of protection from this pain/damage with the saponin Gypenosides (GYP) extracted from Gynostemma pentaphyllum. We have quantified the parameters related to muscle such as muscle power and the resultant hydrodynamic force, proving that GYP could alleviate the detrimental effect of acetic acid on zebrafish larvae, in the form of alleviation from swimming debility, and that the muscle status could be quantified to represent the degree of muscle damage due to the acetic acid and the recovery due to GYP. We have also linked the behavioral changes to alteration of antioxidant and inflammation gene expression. The above results provide novel insights into the reasons for pain-related behavioral changes in fish larvae, especially from an internal muscle perspective, and have quantified these changes to help understand the protection of swimming behaviors and internal muscle by GYP from acetic acid-induced damage

Toxicity of a seafood toxin, domoic acid, in the retina via modulation of the NRF2 and NF-κB pathways

Domoic acid (DA), a biotoxin, is produced by several species of marine dinoflagellate and diatom during harmful algal bloom events. DA is a neurotoxin, in humans and non-human primates, oral exposure to DA results in gastrointestinal effects, while DA at higher doses leads to neurological symptoms, seizures and memory deficiency. Exposure of humans to DA occurs mainly through consumption of contaminated seafoods containing an accumulation of the toxin. Previously, it was unclear if DA can have toxic effects on the retina. We assessed the toxicity of DA in human retinal cells (ARPE-19) and in zebrafish embryos. DA significantly lowered ARPE-19 cell viability dose-dependently, and decreased anti-oxidative capacity, increased inflammation, and promoted cell death, possibly through modulating the NRF2 and NF-κB signalling pathways. Zebrafish embryos exposed to DA for four days from one day post fertilization (dpf) had an increase in mortality and a decrease in both hatching and heartbeat rate and exhibited morphological abnormalities. DA treatment also significantly downregulated expression of antioxidant genes and upregulated expression of inflammation mediators, as well as causing photoreceptor death in zebrafish embryos. The results demonstrate that consuming seafood containing DA will have potential toxic effects in human retinas