BETA-CAROTENE AND CNS OXYGEN-TOXICITY IN RATS

beta-Carotene and CNS oxygen toxicity in rats. J. Appl. Physiol. 76(3) : 1073-1076, 1994. - beta-Carotenes are reported to be potent free rad ical quenchers, singlet oxygen scavengers, and lipid antioxidants. Oxy gen free radicals that are produced in excess during exposure to oxyge n at high pressures and overwhelm the body's normal antioxidant defens e systems seem to mediate the hyperoxic insult. We decided to test the possible protective effect against central nervous system oxygen toxi city of a natural beta-carotene composed of equal amounts of the all-t rans and 9-cis isomers obtained from the unicellular halotolerant alga Dunaliella bardawil. Rats implanted with chronic cortical electrodes for continuous electroencephalogram monitoring were fed on ground comm ercial food enriched with natural beta-carotene (1 g/kg diet). On comp letion of 1 wk of the diet, the rats were exposed to 0.5 MPa oxygen an d then their livers were removed for beta-carotene and vitamin A analy sis. A significant increase was noted in the latent period preceding o xygen seizures in the group of rats in which the diet was supplemented by natural beta-carotene compared with rats given a normal diet (38.5 +/- 3.4 vs. 16.8 +/- 1.8 min; P < 0.05). Further experiments are requ ired to evaluate the potential benefit of supplementing the diet of di vers and patients exposed to high pressures of oxygen with the beta-ca rotene-rich D. bardawil.