Background: Oxidative stress is induced in the liver by application of the Pringle manoeuvre. Malondialdehyde is a carbonyl compound formed during lipid peroxidation and prostaglandin biosynthesis, which combines with DNA to form a number of adducts. Among them is the DNA adduct; 3-(2-deoxybeta-dierythropentafuranosyl) pyr [1, 2-alpha]-purin-10 (3H) one or M1G. This study was undertaken to determine the suitability of M1G as a novel marker of ischemia-reperfusion injury in the liver and its correlation with both the length of Pringle clamp application and the overall length of the operation.
Methods: Normal and colorectal liver metastatic tissues were obtained in 12 patients before and after application of the Pringle manoeuvre. All samples were snap-frozen in liquid nitrogen at -80 degree centigrade. DNA was extracted and M1G quantification was performed by immunoslotblot analysis.
Results: M1G levels in normal liver tissue were 4.0+/-1.0 per 10(7) nucleotides before the Pringle manoeuvre and 7.4 +/-1.0 per 10(7) nucleotides after the Pringle manoeuvre (mean+/-standard deviation) (P<0.05 by ANOVA). M1G levels in malignant liver tissue were 2.5+/-1.4 per 10(7) nucleotides before the Pringle manoeuvre and 6.5+/-1.9 adducts per 10(7) nucleotides after the Pringle manoeuvre (P<0.05). Adduct levels in normal liver tissue showed a significant correlation with cumulative period of Pringle application.
Conclusions: This is the first time that the tissue levels of M1G before and after application of the Pringle manoeuvre have been studied. The results show that the Pringle manoeuvre exerts significant oxidative stress in human hepatocytes, which is Pringle-time dependent. The results highlight the potential for oxidative DNA adducts levels as a tool for measuring the severity of ischemia-reperfusion injury.