Remote ischemic conditioning temporarily improves antioxidant defense

BackgroundRemote ischemic conditioning (RIC) is the most promising surgical approach to mitigate ischemia and reperfusion (IR) injury. It consists in performing brief cycles of IR in tissues other than those exposed to ischemia. The underlying mechanisms of the induced protection are barely understood, so we evaluated if RIC works enhancing the antioxidant defense of the liver and kidney before IR injury.Materials and methodsTwenty-one Wistar rats were assigned into three groups as follows: sham, same surgical procedure as in the remaining groups was performed, but no RIC was carried out. RIC 10, RIC was performed, and no abdominal organ ischemia was induced. After 10 min of the end of the RIC protocol, the liver and kidney were harvested. RIC 60, similar procedure as performed in RIC 10, but the liver and the kidney were harvested 60 min. RIC consisted of three cycles of 5-min left hind limb ischemia followed by 5-min left hind limb perfusion, lasting 30 min in total. Samples were used to measure tissue total antioxidant capacity.ResultsRIC protocol increased both liver (1.064 ± 0.26 mM/L) and kidney (1.310 ± 0.17 mM/L) antioxidant capacity after 10 min when compared with sham (liver, 0.759 ± 0.10 mM/L and kidney, 1.08 ± 0.15 mM/L). Sixty minutes after the RIC protocol, no enhancement on liver (0.687 ± 0.13 mM/L) or kidney (1.09 ± 0.15 mM/L) antioxidant capacity was detected.ConclusionsRIC works through temporary and short-term enhancement of liver and kidney cells antioxidant defenses to avoid the deleterious consequences of a future IR injury.