Antioxidant effects of exogenous polyamines in damage of lysosomes inflicted by xanthine oxidase or stimulated polymorphonuclear leucocytes

Polyamines: Potential anti-inflammatory agents and their possible mechanism of action

Objective:

To evaluate the anti-inflammatory activity of exogenously administered polyamines on experimentally induced acute and chronic inflammation in wistar rats and to elucidate their possible mechanism of action.

Materials and Methods:

The in vivo anti-inflammatory activity of polyamines was studied using acute (carrageenin paw edema), sub-acute (cotton pellet granuloma) and chronic (Freund's adjuvant induced arthritis) models of inflammation. The biochemical parameters like liver lipid peroxides, SGOT and SGPT were also measured.

Results:

Polyamines exhibited significant anti-inflammatory activity in acute, sub-acute and chronic models of inflammation. Polyamines treatment inhibited the increase in lipid peroxides in liver and the serum concentration of marker enzymes (glutamate oxaloacetate transferase and glutamate pyruvate transferase) during inflammation.

Conclusion:

Polyamines possess anti-inflammatory activity in acute and chronic inflammation which can be attributed to their anti-oxidant and /or lysosomal stabilization properties.

Antioxidants suitable for use with chemiluminescence to identify oxyradical species

From a panel of 24 alleged antioxidants the most suitable antioxidants (AO) for use with chemiluminescence (CL) experiments were determined. Superoxide dismutase (SOD), using luminol as the chemiluminescence probe (Lum-CL), was inhibitory only towards O2*- and not HO* or (1)O2. SOD was thus a suitable antioxidant for O2*-, as was tiron. Tiron had advantages, however, since SOD acted as a pro-oxidant in the presence of H2O2 or H2O2/HO* generators. The two most suitable antioxidants for (1)O2 were diphenylisobenzofuran (DBF) and tryptophan, for both Lum and Lucigenin-CL (Luc-CL). Desferrioxamine, with both Lum and Luc-CL, was a very effective scavenger for HO*, but appeared to be an even more effective scavenger for (1)O2. Cysteamine showed the best discrimination between IC50s when the two (1)O2 generators NaOCl/H2O2 and NDPO2 were compared. Cysteamine was, therefore, the only scavenger that was appropriate for studies with hypochlorite. Melatonin, with Lum-CL, was found to be the most suitable scavenger for HO*. Mannitol, the classical AO for HO*, was not suitable when used with CL since it acted as a pro-oxidant. Some of the AOs revealed either calyx- or bell-shaped CL inhibition profiles and presumably, therefore, may act as both pro- or antioxidants at different concentrations. Antioxidants showing these kinds of dual activities should be used with caution in CL studies.

Polyamines in the lung: polyamine uptake and polyamine-linked pathological or toxicological conditions

The natural polyamines putrescine, cadaverine, spermidine, and spermine are found in all cells. These (poly)cations exert interactions with anions, e.g., DNA and RNA. This feature represents their best-known direct physiological role in cellular functions: cell growth, division, and differentiation. The lung and, more specifically, alveolar epithelial cells appear to be endowed with a much higher polyamine uptake system than any other major organ. In the lung, the active accumulation of natural polyamines in the epithelium has been studied in various mammalian species including rat, hamster, rabbit, and human. The kinetic parameters (Michaelis-Menten constant and maximal uptake) of the uptake system are the same order of magnitude regardless of the polyamine or species studied and the in vitro system used. Also, other pulmonary cells accumulate polyamines but never to the same extent as the epithelium. Although different uptake systems exist for putrescine, spermidine, and spermine in the lung, neither the nature of the carrier protein nor the reason for its existence is known. Some pulmonary toxicological and/or pathological conditions have been related to polyamine metabolism and/or polyamine content in the lung. Polyamines possess an important intrinsic toxicity. From in vitro studies with nonpulmonary cells, it has been shown that spermidine and spermine can be metabolized to hydrogen peroxide, ammonium, and acrolein, which can all cause cellular toxicity. In hyperoxia or after ozone exposure, the increased polyamine synthesis and polyamine content of the rat lung is correlated with survival of the animals. Pulmonary hypertension induced by monocrotaline or hypoxia has also been linked to the increased polyamine metabolism and polyamine content of the lung. In a small number of studies, it has been shown that polyamines can contribute to the suppression of immunologic reactions in the lung.

Protective effect of spermine on DNA exposed to oxidative stress

Pathological conditions that cause oxidative stress can affect DNA integrity. The aim of this research was to study the protective effect of spermine against DNA damage induced by an oxygen-radical generating system. Deoxyguanosine and DNA were separately dissolved in phosphate buffer and incubated for 1 h at 40 degrees C in the presence of 50 mM H2O2/10 mM ascorbic acid. Single nucleosides and their products of oxidation were then obtained by enzymatic digestion of DNA. The compounds were separated by micellar electrokinetic capillary chromatography (MECC) with SDS-modified mobile phase and detected at 254 nm. Two major products of DNA oxidation have been identified as derivatives of deoxyguanosine with electrophoretic properties different from 8-hydroxy-2'-deoxyguanosine. When the oxidation of DNA was carried out in the presence of 0.1 mM spermine, the formation of the two by-products of deoxyguanosine was markedly reduced. On the contrary, spermine did not prevent the oxidation of deoxyguanosine alone, suggesting that the polyamine should be bound to the DNA strands to exert its antioxidative effect.

Effect of one hyperbaric oxygen-induced convulsion on cortical polyamine content in two strains of mice

In rat striatum, after one hyperbaric oxygen (HBO)-induced convulsion, polyamine changes are found that could promote N-methyl-D-aspartate (NMDA) activation. In the HBO-sensitive CD1 mouse, unlike in the common C57 strain, there is some support for NMDA activation after the HBO seizure. We measured PA cortical content before and after the first HBO-induced convulsion (about 608 kPa O2) in CD1 and C57 strains. Putrescine, spermidine and spermine were dansyl derived and analysed by HPLC. Exposure to HBO significantly increased putrescine content only in CD1 though a similar trend was observed in C57. No further increase was observed after convulsion whatever the strain. There were no significant changes in spermidine or spermine to support NMDA activation. Therefore, putrescine increase in CD1 cortex could reflect the free radical formation that is known to be greater in CD1 than in C57 mouse. Attempts to increase putrescine levels before HBO exposure hastened HBO-induced convulsion, less than spermidine or spermine. Because of physiological polyamine interconversion, additional experiments with indirect manipulation of putrescine levels and study of their time-course would precise these preliminary reports on putrescine and HBO.

Estradiol-17 beta modifies the induction of spermidine/spermine N1-acetyltransferase activity in the liver of lipopolysaccharide-treated mice

In an attempt to elucidate the effects of estrogen on polyamine metabolism in lipopolysaccharide (LPS)-treated mice, we assayed polyamine content and the activity of spermidine/spermine N1-acetyltransferase (SAT) and ornithine decarboxylase (ODC) in some organs. LPS elevated N1-acetylspermidine levels in the liver and lung and putrescine levels in the liver, lung and spleen. LPS increased the activity of ODC at 6 h and that of SAT at 12 h in the liver. When estradiol-17 beta was simultaneously administered with LPS, the maximum increase in hepatic N1-acetylspermidine levels was found 6 h earlier than in the LPS control. Likewise, the peak of the hepatic SAT activity after LPS-treatment was observed 6 h earlier in the estradiol-17 beta-treated mice than in the LPS control. No such effect of estradiol-17 beta was found in the lung and spleen. The LPS-induced ODC activity was not affected by estradiol-17 beta in the liver, lung or spleen. Estrone and 16 beta-ethylestradiol (an anti-estrogen) were also effective in enhancing the LPS-induced elevation of N1-acetyl-spermidine and putrescine in the liver, while both diethylstilbestrol, which has a potent estrogenic activity without steroid structure and estradiol-17 alpha (a non-estrogenic isomer of estradiol-17 beta) were without effect. Tamoxifen (an estrogen receptor antagonist) did not suppress the estrogen-induced increase in hepatic N1-acetylspermidine levels.

Ischemia- and reperfusion-induced arrhythmias are prevented by putrescine

The influence of putrescine on cardiac arrhythmias induced by either permanent ligature of the left anterior coronary artery or heart reperfusion following a 5-min coronary occlusion was studied in anesthetized rats. Reperfusion-induced arrhythmias were significantly prevented by the i.v. injection of 150-200 mg/kg of putrescine, the survival rate being 100% in treated animals and 40% in controls. At a dose level of 200-300 mg/kg i.v., putrescine also significantly reduced the duration of ventricular tachycardia induced by permanent coronary occlusion. These findings show that putrescine significantly reduces the consequences of cardiac ischemia and reperfusion, probably as a consequence of its multiple stabilizing effects at the membrane level.