Total SOD activity was determined as proposed by Marklund
and Marklund (1974), with the modifications of Gatellier, Mercier,
and Renerre (2004), by measuring the inhibition of pyrogallol
autoxidation. The reaction mixture contained 2850 lL of 50mM
phosphate buffer (pH 8.2), 75 lL of the supernatant and 75 lL of
10 mM pyrogallol. The absorbance at 340 nm was read as soon as
the reaction begin, and the increase in absorbance during the first
2 min was recorded. One unit (U) was defined as the activity that
inhibited the reaction by 50%, the result was expressed as U/g of
muscle.