2.4. Measurement of thiol/disulfide homeostasis
The thiol/disulfide homeostasis parameters were studied with a new method previously described by Erel et al. First, dynamic disulfide bonds (-S-S)were reduced to reactive thiol groups in the presence of sodium borohydride.9 Later, total thiol and native thiol (-SH) levels were determined using Ellman reagents.29 The dynamic disulfide amount was obtained by dividing the difference between the total and native thiol by two. Oxidized thiol, reduced thiol, and thiol-oxidation reduction parameters were calculated according to the formula below. Oxidized thiol [(-S-S-) X 100/ total thiol)], Reduced thiol [(-SH X 100) / total thiol] and Thiol oxidation reduction [(-S-S-) X 100/(-SH)]. Native thiol, total thiol, and disulfide levels were expressed as µmol/L.