Similar effect of sodium nitroprusside and acetylsalicylic acid on antioxidant system improvement in mouse liver but not in the brain.

BACKGROUND

The aim of the present study was to analyze the relative antioxidant effects of acetylsalicylic acid (ASA) and sodium nitroprusside (SNP) in mouse liver and brain.

METHODS

The activity of rhodanese, 3-mercaptopyruvate sulfurtransferase (MPST) and γ-cystathionase (CSE), functioning as antioxidant proteins and capable of producing HS, was investigated in mouse liver and brain after intraperitoneal once a day administration of sodium nitroprusside (5 mg/kg body weight) or acetylsalicylic acid (500 mg/kg body weight) continued for 5 days. The tissues were homogenized and then the obtained supernatants were used for further determinations. At the same time, the levels of sulfane sulfur, reduced and oxidized glutathione, cysteine, cystine, and cystathionine were also studied in these tissues.

RESULTS

Both ASA and SNP show a statistically significant increase of sulfurtransferases activities in liver. The mechanism of action of sodium nitroprusside appears to consist in liberation of nitric oxide (NO), an important signaling molecule in the mammalian body. SNP also releases cyanide ions, which are converted in the liver to thiocyanate by the enzyme rhodanese and/or MPST and/or γ-cystathionase - the activities of all the enzymes were elevated in reaction to SNP. The action of γ-cystathionase is dependent upon converting cystathionine to cysteine, a precursor of the major cellular antioxidant, glutathione. Under oxidizing conditions, an increase in cystathionine β-synthase activity might indirectly result in an increase in the antioxidant glutathione level; this was reflected by the increased GSH/GSSG ratio in the liver, but not in the brain, where a trace activity of γ-cystathionase is normally detected.

CONCLUSION

The results of the present investigations show that ASA and SNP may stimulate the GSH-dependent antioxidant system and protect liver cells from oxidative stress. An increased activity of the HS-producing enzymes and the increased GSH/GSSG ratio may lead to an elevated level of HS, a molecule with antioxidant properties. A similar effect was not observed in the brain. In case of both sodium nitroprusside and aspirin administration, homeostasis of sulfane sulfur level was noted in both the liver and brain.