Okadaic Acid Exposure Induced Neural Tube Defects in Chicken (Gallus gallus) Embryos

Abstract

Okadaic acid (OA) is an important liposoluble shellfish toxin distributed worldwide, and is mainly responsible for diarrheic shellfish poisoning in human beings. It has a variety of toxicities, including cytotoxicity, embryonic toxicity, neurotoxicity, and even genotoxicity. However, there is no direct evidence of its developmental toxicity in human offspring. In this study, using the chicken (Gallus gallus) embryo as the animal model, we investigated the effects of OA exposure on neurogenesis and the incidence of neural tube defects (NTDs). We found that OA exposure could cause NTDs and inhibit the neuronal differentiation. Immunofluorescent staining of pHI3 and c-Caspase3 demonstrated that OA exposure could promote cell proliferation and inhibit cell apoptosis on the developing neural tube. Besides, the down-regulation of Nrf2 and increase in reactive oxygen species (ROS) content and superoxide dismutase (SOD) activity in the OA-exposed chicken embryos indicated that OA could result in oxidative stress in early chick embryos, which might enhance the risk of the subsequent NTDs. The inhibition of bone morphogenetic protein 4 (BMP4) and Sonic hedgehog (Shh) expression in the dorsal neural tube suggested that OA could also affect the formation of dorsolateral hinge points, which might ultimately hinder the closure of the neural tube. Transcriptome and qPCR analysis showed the expression of lipopolysaccharide-binding protein (LBP), transcription factor AP-1 (JUN), proto-oncogene protein c-fos (FOS), and C-C motif chemokine 4 (CCL4) in the Toll-like receptor signaling pathway was significantly increased in the OA-exposed embryos, suggesting that the NTDs induced by OA might be associated with the Toll-like receptor signaling pathway. Taken together, our findings could advance the understanding of the embryo–fetal developmental toxicity of OA on human gestation.

The influence of different sugammadex doses on neural tube development in early‐stage chick embryos

“…First, experimental research on animals may not always be predictive of human responses (Australian Government, 2011; Merck & Co., 2021). The avian embryo model is frequently used, and accepted as beneficial for developmental biology, experimental embryology, and teratology studies in early vertebrates since it is similar to mammalian embryos (Drake et al, 2006; Jiao et al, 2021; Tufan et al, 2007). The windowing technique may become another lingering question under this title (Drake et al, 2006).…”

“…With the advantage of being similar to mammalian embryos, the avian embryo model is widely used and quite valuable for developmental biology, experimental embryology, and teratology studies in early vertebrates (Drake et al, 2006; Jiao et al, 2021). Therefore, the current study aimed to analyze the effects of various sugammadex doses on NT and embryologic development by using the mentioned experimental model.…”

Current Trends and New Challenges in Marine Phycotoxins

“…It has been reported that OA can cause neuronal cell death by inducing hyperphosphorylation of a variety of microtubule-binding proteins, especially Tau protein and neurofibrillary tangles formation, resulting in changes in the neuronal cytoskeleton in vitro and in vivo [ 195 ]. It has been also demonstrated that OA can produce spatial memory impairment and neurodegeneration and cause hippocampal cell loss in rats [ 196 ].…”

Etiology and management of Alzheimer’s disease: Potential role of gut microbiota modulation with probiotics supplementation

“…Okadaic acid is produced by marine microalgae and causes toxicity in the brain. It is a polyether toxin that leads to diarrhetic shellfish toxicity (Jiao et al, 2021;Kamat et al, 2010). It is also involved in memory deficits by inhibition of synaptic activity.…”