Monitoring influence of surgical stress on formation of hydroxyl radicals in tumor bearing rats by measuring salicylic acid metabolites

Hydroxyl radical (HOˇ) is one of the most harmful reactive oxygen species (ROS), which are formed in excess during oxidative stress (shock, sepsis, trauma, surgery, hypoxia, ischaemia-reperfusion, etc.). For measurement of HOˇ indirect methods are used determining aromatic acids hydroxylation products. The most used is salicylic acid whose hydroxylation products 2, 3-dihydroxybenzoic acid (2, 3-DHBA) and 2, 5-dihydroxybenzoic acid (2, 5-DHBA) can be separated and quantified by HPLC method with electrochemical detection. As 2, 5-DHBA can be produced also by enzymatic pathway, only 2, 3-DHBA serves as a measure for HOˇ radical production. The purpose of this work was to investigate HOˇ formation in surgically treated tumour bearing rats and to see whether difference in HOˇ production can be seen between healthy and tumour bearing animals. In normal, healthy rats increase in 2, 3-DHBA production was measured when they were surgically treated by laparatomy only (p<0, 05) or by laparatomy followed by I/R (p<0, 05). Such response was not noticed in tumour bearing rats where increase in 2, 3-DHBA production was not observed neither in animals exposed to laparatomy only nor if laparatomy was followed by the tumour I/R. The difference observed between operated controls and tumour bearing rats was significant (p<0, 05). For 2, 5-DHBA production, there was no difference observed between operated and non-operated rats for both control and tumour bearing animals.