ALTERED GLUTATHIONE LEVELS IN ISCHEMIC AND POSTISCHEMIC SKELETAL-MUSCLE - DIFFERENCE BETWEEN SEVERE AND MODERATE ISCHEMIC INSULT

The purpose of the present study was to investigate how the duration o f ischemia and reperfusion affect the glutathione (GSH) levels in skel etal muscle and to assess the presence of oxidative stress by quantita ting oxidized glutathione (GSSG) and the ratio of GSSG/GSH. The amount s of GSH and GSSG were quantitated in the tibialis anterior muscle of the rat hind limb after 2 and 4 hours of tourniquet ischemia and after 1 and 5 hours of reperfusion, and the levels were compared to those i n nonischemic control tibialis anterior muscles, In muscles subjected to 2 hours of ischemia, the levels of GSH, GSSG, and the ratio GSSG/GS H did not differ significantly from those of nonischemic controls, Aft er 4 hours of ischemia without reperfusion, the GSH levels were slight ly increased, compared to controls (p < 0.05), After 1 hour of reperfu sion following 4 hours of ischemia, the levels of GSH decreased by 50% compared to control (p < 0.01), and still after 5 hours of reperfusio n the levels of GSH were 50% lower than control levels, The GSSG/GSH r atio did not change during 1 and 5 hours of reperfusion compared to co ntrol, A major finding in this study was that, during reperfusion afte r severe ischemia of 4 hours, there was a marked depletion of glutathi one, which was not seen after a moderate ischemic insult of 2 hours.