Thallium stimulates ethanol production in immortalized hippocampal neurons

Abstract

Lactate and ethanol (EtOH) were determined in cell culture medium (CCM) of immortalized hippocampal neurons (HN9.10e cell line) before and after incubation with Thallium (Tl). This cell line is a reliable, in vitro model of one of the most vulnerable regions of central nervous system. Cells were incubated for 48 h with three different single Tl doses: 1, 10, 100 μg/L (corresponding to 4.9, 49 and 490 nM, respectively). After 48 h, neurons were “reperfused” with fresh CCM every 24/48 h until 7 days after the treatment and the removed CCM was collected and analysed. Confocal microscopy was employed to observe morphological changes. EtOH was determined by head space—solid phase microextraction -gas chromatography -mass spectrometry (HS-SPME-GCMS), lactate by RP-HPLC with UV detection. Tl exposure had significant effects on neuronal growth rate and morphology. The damage degree was dose-dependent. In not exposed cells, EtOH concentration was 0.18 ± 0.013 mM, which represents about 5% of lactate concentration (3.4 ± 0.10 mM). After Tl exposure lactate and EtOH increased. In CCM of 100 and 10 μg/L Tl-treated cells, lactate increased 24 h after reperfusion up to 2 and 3.3 times the control value, respectively. In CCM of 10 and 100 μg/L Tl-treated cells 24 h after reperfusion, EtOH increased up to 0.3 and 0.58 mmol/L. respectively. These results are consistent with significant alterations in energy metabolism, despite the low doses of Tl employed and the relatively short incubation time.

A Two-Step GRIN Lens Coating for In Vivo Brain Imaging

“…The federal maximum contaminant level for thallium in drinking water is 0.5 lg/L according to the US Environmental Protection Agency (https://www.epa.gov/sites/production/ files/2015-06/documents/ny_hh_255_w_09241998.pdf). A previous study showed that 48-h exposure to 100 lg/L thallium induces the complete loss of neurites in cultured hippocampal neurons [13]. Next, we cultured hippocampal neurons in the presence of uncoated lenses for 15 days.…”

Toxicity of Thallium at Low Doses: A Review

“…While Tl effects in acute intoxication are well known [18], as well as those on biological systems at high concentrations [19,20,21,22,23,24], the effects of Tl at low doses and for short exposure periods on cell cultures have only recently been evaluated [25,26].…”

“…However, even a single 48 h exposure to Tl + doses more than 50 times lower (1, 10, and 100 μg/L) have been found to have significant effects on neuronal growth rate and morphology [25,26]. An early-onset mitochondrial dysfunction appears after Tl + exposure, which is associated with signs of cellular deregulation such as neurite shortening, loss of substrate adhesion, and increase of cytoplasmic calcium.…”

“…The dose-dependent alteration of mitochondrial ROS (mtROS) levels and transmembrane mitochondrial potential (ΔΨm) have been also observed at very low Tl concentrations (1 μg/L). The contents of ethanol and lactate are significantly and dose-dependently altered after Tl exposure [25,26].…”

Unraveling the Extracellular Metabolism of Immortalized Hippocampal Neurons Under Normal Growth Conditions

“…Recently, we published a study on the metabolic implications on the neuronal metabolism of the HN9.10e cell line following a short and transient exposure to low thallium chloride doses, based on the chromatographic analysis of CCM and on morphological and functional tests (Colombaioni et al, 2017b). This neuronal cell line presents structural and functional features analogous to primary hippocampal neurons and represents a reliable in vitro model of one of the most vulnerable regions of the central nervous system (Lee et al, 1990).…”