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Aging at the cellular level is characterized by oxidative stress, inflammation, and cell senescence. An extract of the brown seaweed Ascophyllum nodosum rich in phlorotannins has been studied for its inhibitory activity against oxidative stress, inflammation, and senescence. A. nodosum extract at 0.2 % prevented tBHP-induced reactive oxygen species production (evaluated using the H2DCF-DA test in cytofluorometry) in epithelial cells and LPS-induced TNF-α and IL-6 release (evaluated using ELISA technique) in macrophages. A. nodosum extract also increased nuclear SIRT1 activity in epithelial cells. Altogether, these beneficial cellular effects of phlorotannin-rich A. nodosum extract could be used in topical therapeutic formulations against aging.

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The cytotoxicity observed with fluoroquinolone eye drops seems to be caused mainly by the preservative, which induced P2X7 cell death receptor activation associated with oxidative stress and apoptosis. Therefore, it is recommended that fluoroquinolone be used in preservative-free formulations.

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Background: Bisphenol A (BPA), a reprotoxic and endocrine-disrupting chemical, has been substituted by alternative bisphenols such as bisphenol F (BPF) and bisphenol S (BPS) in the plastic industry. Despite their detection in placenta and amniotic fluids, the effects of bisphenols on human placental cells have not been characterized. Our objective was to explore in vitro and to compare the toxicity of BPA to its substitutes BPF and BPS to highlight their potential risks for placenta and then pregnancy. Methods: Human placenta cells (JEG-Tox cells) were incubated with BPA, BPF, and BPS for 72 h. Cell viability, cell death, and degenerative P2X7 receptor and caspases activation, and chromatin condensation were assessed using microplate cytometry and fluorescence microscopy. Results: Incubation with BPA, BPF, or BPS was associated with P2X7 receptor activation and chromatin condensation. BPA and BPF induced more caspase-1, caspase-9, and caspase-3 activation than BPS. Only BPF enhanced caspase-8 activity. Conclusions: BPA, BPF, and BPS are all toxic to human placental cells, with the P2X7 receptor being a common key element. BPA substitution by BPF and BPS does not appear to be a safe alternative for human health, particularly for pregnant women and their fetuses.

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A B S T R A C TThe YO-PRO-1 assay provides a quantitative estimation of P2X7 receptor activation. P2X7 receptor is associated to pathological conditions including infectious, inflammatory, neurological, musculoskeletal disorders, pain and cancer. Most primary cells and cell lines from diverse origin may be used thanks to the ubiquitous distribution of P2X7 receptor. To study the activation of P2X7 receptor by chemicals or biological agents, we established a microplate-based cytometry protocol to accurately and rapidly quantify the activation of P2X7 receptor that leads to the formation of large pores in cell membranes. The YO-PRO-1 assay is based on the ability of cells to incorporate and bind YO-PRO-1 dye to DNA after activation of P2X7 receptor through pore formation. Cells are seeded in 96-well plates and incubated with the compound being tested for the appropriate time. The microplate is then incubated for 10 min with YO-PRO-1 staining solution. After the 10 min staining time, fluorescence signal is read using a microplate reader in 1 min. This procedure is easier and requires less handling steps than flow cytometry. 96-well plate based YO-PRO-1 assay is a reproducible and fast method to study both P2X7 receptor activation by toxic agents at subnecrotic concentrations and P2X7 receptor inhibition by antagonists.