Aim: The present study tests the hypothesis, that the iron chelator DFO prevents the free radical-induced decrease of cell membrane Na+,K+-ATPase activity in cerebral cortical tissue of newborn lambs following HI. Methods: HI was induced in 10 newborn lambs by decreasing FiO2 to 0.08 for 30 min, followed by 5 min of hypotension(MABP <35 mmHg). During HI electrocortical brain activity dropped to virtually 0 μV in all animals. Immediately after HI 5 lambs received DFO(2.5 mg/kg, i.v.), 5 other lambs were given normal saline. After 180 min the brains were obtained and frozen until analysis. Results: Na+,K+-ATPase activity was measured in the P2-fraction of cortical tissue. Na+,K+-ATPase activity in untreated HI lambs was 36.4 ± 4.4 μmol Pi/mg protein/h compared to 42.6 ± 9.2 in DFO treated lambs (differences N.S.). The decrease of Na+,K+-ATPase activity in these lambs following HI is similar to the decrease observed in newborn piglets and fetal guinea-pigs. Conclusion: Na+,K+-ATPase activity tended to be higher in cortical cell membranes of cerebral tissue of DFO-treated lambs. These results do not preclude, that NPBI plays a role in free-radical induced brain cell membrane injury following HI.

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