Search

Degenerative neurological diseases (senile dementia, Alzheimer`s disease, glaucoma), post-stroke sequelae are increasing as prevalence nowadays, in context of aging in general population, and there are strong evidences that astrocytes may play a significant role in neuroprotection. The study evaluates the effects of low intensity low frequency electromagnetic field (EMF) �in vitro� stimulation (195 mA, 7-8 Hz) on the glial cells, in different conditions, in order to identify the neuroprotective potential. Three cell lines were used for the study: the Clonetics (Lonza) line of normal human astrocytes, U87 glioblastoma tumor cells (ATCC) and L929 murine fibroblasts. The cell cultures were exposed to EMF stimulation for 2 hours/day, for 5 and 10 day, in absence and in the presence of oxidative stress stimuli. Cell viability, apoptotic potential, changes in cell phenotype, stimulation of cell proliferation for normal and malignant transformed cell lines, resilience to oxidative stress were investigated. The viability of the cells was investigated by MTS assay, and the Griess test was used to detect nitrite production as a marker of oxidation and inflammation. Inverted microscopy examination revealed that following exposure to the tested EMF, no morphological changes of the cells were recorded. In none of the cell lines tested, no cytotoxic or cytopathic effects were observed in the cultures exposed under low density conditions. In case of exposure of cell cultures for 10 days to the action of EMF, a viability of 98.2% of glial cells and 97% of exposed fibroblasts is observed, compared to unexposed cells. The viability of the cells exposed to both EMF and oxidative and inflammatory stimuli is increased by 0.96% in the case of H2O2 stimulation and in 3.76% in the case of LPS stimulation, suggesting a possible neuroprotective effect of EMF exposure. Low intensity low frequency EMF �in vitro� stimulation increased viability of the glial cells exposed to oxidative and inflammatory stimuli. No cytotoxic or cytopathic effects were observed in the exposed cultures under conditions of low density. Further tests are needed in order to elucidate the mechanisms of action of EMF on astrocytes, especially on astrocyte-neuron co-cultures to highlight the interactions between these cell types. Confirmation of the neuroprotective effect of low intensity and low frequency EMF opens the way for the development of an innovative, non-invasive therapy.

Heat shock inductors have potential as treatment for degenerative and protein misfolding diseases. Dimethyl-sulfoxide is widely used as a solvent in pharmacological screening tests and has been shown to have heat shock induction effects. Transgenic Tg (hsp70l:EGFP-HRAS_G12V)io3(AB) zebrafish larvae were exposed for 24 hours to dimethyl-sulfoxide in concentratios of 0.1-2%, and to moderate heat shock inductors pentoxifylline and tacrolimus. Positive controls were exposed to 35, 38 and 40�C for 20 min, and incubated for 24 h at 28�C. Heat shock response was measured by fluorescence microscopy and signal intensity quantification in FIJI. Dimethyl-sulfoxide caused a dose-dependant increase in fluorescent intensity, but significantly lower compared with exposure to 38 and 40�C. Pentoxifylline and tacrolimus induced a significantly higher increase in fluorescence compared with 0.5% dimethyl-sulfoxide. Thus, although dimethyl-sulfoxide has independent heat shock induction effects, concentrations of up to 0.5% are suitable for heat shock response screening tests.