Dimethyl-sulfoxide is a Suitable Solvent for Fluorescent Microscopy Detection of Medium and Strong Heat Shock Inductors Using Transgenic Zebrafish

Abstract

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.