Silicon as neuroprotector or neurotoxic in the human neuroblastoma SH-SY5Y cell line

[Display omitted] •Silicon show a double-edged-sword effect depends on the concentrations used.•Silicon at high doses may act as neurotoxic by necrosis and apoptosis mechanisms.•Silicon at low doses may act as neuroprotector by inducing anti-apoptotic effects. Silicon (Si) is a trace element that has been considered to be an environmental contaminant for many years, although different studies have recently reported it is an essential element for living cells. The present study tested the ability of different concentrations of Si G57™ to induce neuroprotection or neurotoxicity over 24h in the SH-SY5Y human neuroblastoma cell line. Cell viability, cellular proliferation, LDH release, ROS, antioxidant capacity, TBARS, caspase-3, -8 and -9, DNA fragmentation, and TNF-α levels were evaluated. Low Si doses (50–250ngmL−1) increased the cell viability and reduced caspase-3 and -8 activities and TNF-α level. The increase in cell viability was independent of any proliferative effect as there was no variation in cyclin E and PCNA levels. At higher concentrations, Si increased caspase-3, as well as TBARS, LDH, DNA fragmentation, and TNF-α releases. Altogether, these results suggest that Si could act either as a neuroprotector or a neurotoxic agent depending on the concentration tested. This study emphasizes the importance of developing new neuroprotective therapies based on low Si doses.