Research

Sodium nitroprusside and peroxynitrite effect on hepatic DNases: an in vitro and in vivo study

Gordana Kocic¹ , Dusica Pavlovic¹ , Radmila Pavlovic² , Goran Nikolic² , Tatjana Cvetkovic¹ , Ivana Stojanovic¹ , Tatjana Jevtovic¹ , Radivoj Kocic³ and Dusan Sokolovic¹

¹  Institute of Biochemistry, Medical Faculty University of Nis, Serbia and Montenegro

²  Institute of Chemistry, Medical Faculty University of Nis, Serbia and Montenegro

³  Clinic for Endocrinology, Faculty of Medicine University of Nis, Serbia and Montenegro

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Comparative Hepatology 2004, 3:6doi:10.1186/1476-5926-3-6

Published:	31 August 2004

Abstract

Background

It has been documented that nitric oxide (NO) donor sodium nitroprusside (SNP) and authentic peroxynitrite are capable of promoting apoptosis in a number of different cell types. Various endonucleases have been proposed as candidates responsible for the internucleosomal cleavage of the genomic DNA observed during apoptosis, but the main effect is attributed to the alkaline-DNases (Mg²⁺- and caspase-dependent) and acid-DNase. The aim of this study was to examine an in vivo and in vitro possibility for alkaline- and acid-DNases to be activated by SNP and peroxynitrite.

Results

The effect on liver tissue alkaline and acid DNase activity together with the markers of tissue and plasma oxidative and nitrosative stress (lipid peroxidation, SH group content, carbonyl groups and nitrotyrosine formation) was investigated in plasma and liver tissue. The activity of liver alkaline DNase increased and that of acid DNase decreased after in vivo treatment with either SNP or peroxynitrite. A difference observed between the in vivo and in vitro effect of oxide donor (i.e., SNP) or peroxynitrite upon alkaline DNase activity existed, and it may be due to the existence of the "inducible" endonuclease. After a spectrophotometric scan analysis of purified DNA, it was documented that both SNP and peroxynitrite induce various DNA modifications (nitroguanine formation being the most important one) whereas DNA fragmentation was not significantly increased.

Conclusion

Alkaline DNase activation seems to be associated with the programmed destruction of the genome, leading to the fragmentation of damaged DNA sites. Thus, the elimination of damaged cells appears to be a likely factor in prevention against mutation and carcinogenesis.