Complex mechanisms of tetrabromobisphenol A neurotoxicity in primary cultures of rat cerebellar granule cells

• Autorzy: Zieminska E. , Stafiej A. , Lazarewicz J.W.
• Języki publikacji: EN

Abstrakty

EN

Tetrabromobisphenol A (TBBPA) is a brominated flame retardant considered as the environmental toxin affecting the brain. The exact molecular mechanisms of the TBBPA-induced neurotoxicity are unclear, however recent studies suggest a role of the NMDA receptor-mediated excitotoxicity and/or of calcium imbalance. To verify this hypothesis in the present study we examined relation between toxicity of TBBPA applied to cultured neurons at the micro molar concentration range and activation of the NMDA receptors as well as changes in the intracellular calcium homeostasis, oxidative stress and a decrease in the mitochondrial membrane potential. Experiments were performed using an in vitro model of the primary cultures of rat cerebellar granule cells at 7th day in vitro. To evaluate TBBPA neurotoxicity, the cells were exposed for 30 min to TBBPA, and neuronal viability was tested after 24 h with propidium iodide staining. Changes in calcium homeostasis were characterized by measuring 45Ca uptake and increases in fluorescence of calcium-sensitive probe fluo-3. Changes in the mitochondrial membrane potential and in free radical production were evaluated using the fluorescent probes rhodamine 123 and DCF, respectively. The results demonstrated that TPPBA in the concentration-dependent manner in the range of 25 - 100µM induced severe neurotoxicity. TBBPA in concentrations exceeding 5 µM triggered rise in the intracellular calcium level, which was sensitive to inhibitors of ryanodine receptors 2.5 µM bastadin 10 with 200 µM ryanodine, but not to 2ABP, which inhibits IP3 receptors. TBBPA in concentrations above 25µM activated 45Ca uptake, which was sensitive to uncompetitive NMDA receptor antagonist 0.5 µM MK-801. Moreover we observed accumulation of the reactive oxygen species and a drop in the mitochondrial membrane potential evoked by TBBPA applied at micro molar concentrations. The toxic effect of TPPBA in concentrations up to 10 - 15 µM was insensitive to antagonists of NMDA receptors and ryanodine receptors, MK-801 and bastadin 10 with ryanodine, respectively. This points to a role of the mechanism of TBBPA neurotoxicity other than excitotoxicity and calcium imbalance. Tentatively we identify it as the oxidative stress. Collectively, these data point to complexity of the mechanisms of toxic effects of TBBPA. Depending of TBBPA concentrations they comprise oxidative stress, the release of calcium from ryanodie sensitive stores in endoplasmic reticulum and activation of NMDA receptors. This work was supported by the Polish MNiSW grant N N401 024635.

• Wydawca: -
• Czasopismo: Acta Neurobiologiae Experimentalis
• Rocznik: 2011
• Tom: 71
• Numer: 1
• Opis fizyczny: p.151

Twórcy

autor

Zieminska E.

• Mossakowski Medical Research Centre, Department of Neurochemistry, Polish Academy of Sciences, Warsaw, Poland

autor

Stafiej A.

• Mossakowski Medical Research Centre, Department of Neurochemistry, Polish Academy of Sciences, Warsaw, Poland

autor

Lazarewicz J.W.

• Mossakowski Medical Research Centre, Department of Neurochemistry, Polish Academy of Sciences, Warsaw, Poland