Analysis of oxidant and antioxidant system in experimental liver ischemia reperfusion injury in guinea pigs

98 VIII. SUMMARY The tissue damage after ischemia-reperfusion and the effect of this to blood parameters have significant importance on transplantatin issue of which medicine contemporarily deals with. The equilibrium between the formation and excretion of reactive oxygen molecules formed after injury was kept constant by autioxidative defence system. When reactive oxygen molecules can not be met by antioxidant system in pathological states such as ischemia-reperfusion, oxidative stress ensues. All blood vessels entering or leaving the liver were clamped experimentally for 60 minutes in thirty-one female guina-pigs and then reoxigenized in the following 30 minutes. The two seperate groups received SOD and allopurinol in various times of ischemia. At the end of the procedure, the degree of ischemic injury and the efficacy of antioxidant agents were evaluated by using antioxidant system and by histopathologic examination. SOD,GSH-Px were determined as the key enzymes of antioxidant system, GSH, whereas Na+- K+ ATPase, MDA levels in tissues and plasma, and serum Zn, Cu were assessed as an indicator of tissue damage. Tissue and plasma MDA levels were significantly higher in ischemia- reperfusion group when compared to sham group. It was found that ischemic injury markedly improved in the SOD and allopurinol receiving groups when these two groups were compared to ischemia-reperfusion group. It was also determined that ATPase activity was significantly lower in ischemia-reperfusion group in respect to sham group, whereas it was higher in the other groups. The results for intracellular antioxidants were somewhat different and were as follows. GSH-Px activity was significantly low in ischemia-reperfusion induced injury group compared to sham group (p<0.05), whereas there was a marked increase in parameters when ischemia- reperfusion and antioxidant groups were compared. This showed that exogenous antioxidant application to both groups supported the antioxidant defense system of the body. On the other hand, it was determined that SOD activity showed significant difference in all 3 groups when compared to sham group, whereas there was no significant difference between ischemia-reperfusion group and the other two groups that received antioxidants.99 These results revealed that exogenous antioxidants did not have a meaningful effect on the values of SOD in guinea pig erythrocytes that underwent ischemia-reperfusion injury. GSH levels of all groups were not different from sham group and major degenerations with changes similiar to cellular death were observed in the group that received. Ischemia-reperfusion whereas, a nearly normal or absolutely improved cell structure was observed in allopurinol group. Althought minimal there was still congestion and dilatation of central veins in SOD receiving group. Serum Cu levels were significantly low in ischemia-reperfusion group whereas there was no difference among other groups (p<0.05). the increased levels of the group that receiving only SOD as an antioxidant were statistically significant compared to ischemia-reperfusion group. Serum Zn levels showed significant difference in allopurinol receiving group (p<0.05). the other groups did not have any significant difference. In conclusion, these results showed that antioxidant capacity decreases as a result of increase in oxidative injury, consecutively exogenous antioxidants can be effectively used in the treatment of ischemia-reperfusion injury causes major changes and several complications in many organs and liver, which is the key point of the metabolism.