Severe total hepatic ischemia and reperfusion: Relationship between very high alpha-tocopherol uptake and lipid peroxidation

Reperfusion injury of the liver occurs in liver transplantation and in majo r hepatectomies. It triggers a severe oxidative stress that leads to increa sed lipid peroxidation. In our study we examined the effect of parenteral s upranutritional administration of alpha -tocopherol, a vitamin that plays a key role in the endogenous antioxidant system, to rats subjected to severe ischemia/reperfusion (I/R) injury of the liver. alpha -Tocopherol was admi nistered to the animals at doses of 30 and 300mg/kg bw, whereas total hepat ic ischemia was induced for 60 min followed by 120 min reperfusion. Tissue and blood samples were collected for malonyldialdehyde (MDA) and serum alph a -tocopherol assay, respectively. In the sham operation group, mean MDA le vel in liver was 1.14 nmole/g wet tissue in the control subgroup, and 1.01 or 0.74 nmole/g wet tissue in the subgroups given 30 or 300mg/kg alpha -toc opherol. In the I/R group, mean MDA level was 1.57 nmole/g wet tissue in th e control subgroup, and 0.97 and 0.77 nmole/g wet tissue in the subgroups g iven 30 or 300mg/kg alpha -tocopherol. Mean levels of a-tocopherol in serum (mu mole/l) were 10.20 and 1.80 in the control subgroups, 25.28 and 11.25 in the subgroups treated with 30 and 300 mg/kg bw of alpha -tocopherol, and 31.00 and 13.02 in the subgroups treated with 30 and 300 mg/kg bw of alpha -tocopherol, within the sham-operation and I/R groups, respectively. A sig nificant decrease of MDA accompanied by a significant increase of serum alp ha -tocopherol was documented in the alpha -tocopherol-treated rats within both groups. Ischemia/reperfusion triggered a significant increase of the M DA level in the liver of the rats not treated with alpha -tocopherol as com pares with the treated animals.