Adaptations of the antioxidant system in erythrocytes of trained adult rats: Impact of intermittent hypobaric-hypoxia at two altitudes

Abstract

We have investigated the effects of daily exposure to intermittent hypobaric-hypoxia to two simulated altitudes (5700 m and 6300 m) in adult male rats that had been regularly swim trained in normoxia at sea level prior to exposures. Superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) along with the oxidative stress (OS) indices, malondialdehyde (MDA) and protein carbonyl content were measured in erythrocytes and their membranes. Hemoglobin increased in the trained animals exposed to 5700 m and in untrained rats exposed to 6300 m. Osmotic fragility in terms of hemolysis increased in altitude exposed animals. SOD increased in those exposed to 6300 m, while CAT increased in trained rats exposed to 5700 m and to 6300 m unlike in untrained rats where CAT increased only at 6300 m. GSH-Px showed varying degrees of elevation in all animals exposed to both altitudes. Erythrocyte membranes showed significant elevations in malondialdehyde (MDA) at 6300 m, while elevated protein carbonyls were noticeable at both altitudes in whole cells and membranes. These results suggest a positively associated elevation in protein oxidation with altitude in trained rats. At 5700 m, animals were less stressed, unlike at 6300 m, as seen from the magnitude of elevations in the OS indices and from the responses of the antioxidant enzymes. D

Oxidative stress in erythrocytes: a study on the effect of antioxidant mixtures during intermittent exposures to high altitude

“…Oxidation of proteins by free radicals plays a major role in many oxidative processes within the cells, the magnitude of which is often measured by the carbonyl content (Hawkins and Davies 2001). Oxidative modification of proteins, considering their multiple functions, unlike LPO, can be selective and specific (Adams et al 2001). It is worth noting that membrane proteins are the major targets of postbiosynthetic alterations during erythrocyte intravascular aging, a situation similar to OS, wherein increased generation of free radicals occur (Gallagher et al 1998).…”

“…The latter two form a substantial defense network against oxidative stress imposed by several other factors such as physical exercise (Asha et al 2005;Cooper et al 2002).…”

“…The procedure for exposure of animals to IHH was essentially that reported in an earlier work (Asha et al 2005). In brief, the altichamber consisted of a thickwalled high pressure resistant glass animal chamber fitted with brass lid and with three brass outlets connected to the other components of the unit via vacuum tubes.…”

Oxidative stress and intracellular pH in the young and old erythrocytes of rat

“…Blood was drawn as previously reported (Asha et al , 2005 from the heart into 10% EDTAcoated tubes and erythrocytes were separated by the method of Dodge et al (1963). Blood was drawn as previously reported (Asha et al , 2005 from the heart into 10% EDTAcoated tubes and erythrocytes were separated by the method of Dodge et al (1963).…”

Peroxyl-induced oxidative stress in aging erythrocytes of rat

“…It has also been found that erythrocytes equilibrated at low pH show increased phagocytosis since acidification of RBC increases the interaction with monocytes (Biondi et al 2002). Our earlier studies on in vivo (Asha Devi et al 2005) and in vitro models (Vani et al 2010;Shiva Shankar Reddy et al 2007) of oxidative stress in rat erythrocytes have demonstrated the beneficial effects of using antioxidants, vitamin E and C in preventing stress-induced injury. It is clear therefore that a considerable interaction exists between antioxidant system and oxidative damage to membrane proteins and lipids in mammalian erythrocytes treated with 2, 2 0 -azobis (2-aminidinopropane) dihydrochloride (AAPH), a water-soluble peroxyl radical initiator (Asha Zou et al 2001).…”