O-ß-N-Acetyl-D-glucosaminidase in erythrocytes of Italian air force acrobatic pilots

Objectives: Italian Air Force acrobatic pilots are occupationally susceptible to oxidative stress damage that can lead to overt signs and symptoms of hypoxia (1). Glycohydrolases are found on the plasma membrane and in the cytosol of human erythrocytes (2). Membrane and/or cytosol enzymes are involved in cellular aging, in signaling early membrane alterations (3) and in pathologies involving strong oxidative stress and physico-chemical alterations of the erythrocyte plasma membrane, such as Down’s syndrome (4). We propose erythrocyte glycohydrolases as new, sensitive markers to assess oxidative stress. We undertaken a study to compare Italian Air Force Acrobatic pilots and healthy subjects, closely controlled as regards their nutritional condition, for oxidative stress and the levels of these glycohydrolases as markers of cellular alteration. Erythrocytes, with their 120-day life-span, offer a useful model for investigations during the pilot’s three-month intensive training period. Methods: We measured erythrocyte levels of ß-D-glucuronidase, hexosaminidase, O-ß-N-acetyl-D-glucosaminidase, plasma membrane fluidity and plasma hydroperoxides from 19 pilots in comparison with 40 matched healthy subjects. Results: Plasma hydroperoxide levels and the erythrocyte ghosts’ fluorescence anisotropy were significantly lower in the pilots. Levels of ß-D-glucuronidase, O-ß-N-acetyl-D-glucosaminidase and hexosaminidase in pilots were significantly different from controls, respectively lower, higher and higher. Conclusions: Pilots, in spite of their oxidative stress, are better protected than controls, probably as a result of their physical training and proper diet. Our results confirm that erythrocytes, with their 120-day span-life, are a useful model for investigating physiopathological conditions and that glycohydrolases are good markers for monitoring oxidative stress even in healthy people.