TCDD-induced mitochondrial superoxide production does not lead to mitochondrial degeneration or genomic instability in human SH-SY5Y neuroblastoma cells

The SH-SY5Y human neuroblastoma cell line, a relevant in vitro cell model for investigating neurotoxicology in human: focus on organic pollutants

Investigation of the toxicity triggered by chemicals on the human brain has traditionally relied on approaches using rodent in vivo models and in vitro cell models including primary neuronal cultures and cell lines from rodents. The issues of species differences between humans and rodents, the animal ethical concerns and the time and cost required for neurotoxicity studies on in vivo animal models, do limit the use of animal-based models in neurotoxicology. In this context, human cell models appear relevant in elucidating cellular and molecular impacts of neurotoxicants and facilitating prioritization of in vivo testing. The SH-SY5Y human neuroblastoma cell line (ATCC® CRL-2266^TM) is one of the most used cell lines in neurosciences, either undifferentiated or differentiated into neuron-like cells. This review presents the characteristics of the SH-SY5Y cell line and proposes the results of a systematic review of literature on the use of this in vitro cell model for neurotoxicity research by focusing on organic environmental pollutants including pesticides, 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD), flame retardants, PFASs, parabens, bisphenols, phthalates, and PAHs. Organic environmental pollutants are widely present in the environment and increasingly known to cause clinical neurotoxic effects during fetal & child development and adulthood. Their effects on cultured SH-SY5Y cells include autophagy, cell death (apoptosis, pyroptosis, necroptosis, or necrosis), increased oxidative stress, mitochondrial dysfunction, disruption of neurotransmitter homeostasis, and alteration of neuritic length. Finally, the inherent advantages and limitations of the SH-SY5Y cell model are discussed in the context of chemical testing.

Plant-Derived Natural Biomolecule Picein Attenuates Menadione Induced Oxidative Stress on Neuroblastoma Cell Mitochondria

Several bioactive compounds are in use for the treatment of neurodegenerative disorders, such as Alzheimer’s and Parkinson’s disease. Historically, willow (salix sp.) bark has been an important source of salisylic acid and other natural compounds with anti-inflammatory, antipyretic and analgesic properties. Among these, picein isolated from hot water extract of willow bark, has been found to act as a natural secondary metabolite antioxidant. The aim of this study was to investigate the unrevealed pharmacological action of picein. In silico studies were utilized to direct the investigation towards the neuroprotection abilities of picein. Our in vitro studies demonstrate the neuroprotective properties of picein by blocking the oxidative stress effects, induced by free radical generator 2-methyl-1,4-naphthoquinone (menadione, MQ), in neuroblastoma SH-SY5Y cells. Several oxidative stress-related parameters were evaluated to measure the protection for mitochondrial integrity, such as mitochondrial superoxide production, mitochondrial activity (MTT), reactive oxygen species (ROS) and live-cell imaging. A significant increase in the ROS level and mitochondrial superoxide production were measured after MQ treatment, however, a subsequent treatment with picein was able to mitigate this effect by decreasing their levels. Additionally, the mitochondrial activity was significantly decreased by MQ exposure, but a follow-up treatment with picein recovered the normal metabolic activity. In conclusion, the presented results demonstrate that picein can significantly reduce the level of MQ-induced oxidative stress on mitochondria, and thereby plays a role as a potent neuroprotectant.

Maternal exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin suppresses male reproductive functions in their adulthood

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a ubiquitous environmental contaminant in the environment. The developmental period is more sensitive to TCDD and there is a possibility that maternal exposure to TCDD may affect in adulthood. Adult female Wistar rats were exposed to 0.5, 1.0, and 2.0 µg/kg TCDD during the critical stage of organogenesis, that is, on GD15. The results revealed a significant decrease in indices of reproductive organ weight in adult male rats exposed to prenatal TCDD, and dose-dependent reduction in epididymal sperm reserves, percent motile, and viable sperm with an increase in percent morphological abnormal sperm. Polymerase chain reaction analysis revealed downregulated expression levels of steroidogenic markers such as steroidogenic acute regulatory, cholesterol side-chain cleavage, and 3β- and 17β-hydroxysteroid dehydrogenase (HSDs) in experimental rats. Immunofluorescence sections portrayed reduced distribution of 3β- and 17β-HSD proteins in testes of experimental rats. Furthermore, spermatogenic markers (acid phosphatase, alkaline phosphatase, lactate dehydrogenase, and sorbitol dehydrogenase) were significantly altered in the testes. Serum levels of testosterone, follicle stimulating hormones, and luteinizing hormone were significantly decreased. Testicular levels of hydrogen peroxide and lipid peroxidation were significantly elevated with a decline in superoxide dismutase, catalase, glutathione peroxidase activities, and total thiol levels. Moreover, histological and morphometric examination of testicular cross-sections depicted degenerative changes. Male fertility assessment in adult rats revealed a significant decrease in mating index, fertility index, and mean number of pre- and postimplantations with an increase in pre- and postimplantation losses in rats cohabited with in utero TCDD-exposed adult males. In conclusion, the findings of this study provided clear evidence that maternal exposure to TCDD during the critical stage of development results in suppressed reproductive health in adulthood.