Lipid peroxidation in the rat brain after CO inhalation is temperature dependent

We reported previously that 7-hydroperoxycholesterols, 7 alpha- and 7 beta -hydroperoxycholest-5-en-3 beta -ol (7 alpha -OOH and 7 beta -OOH), indicat ed lipid peroxidation [1]. In the present study, we measured not only 7-hyd roperoxycholesterols but also oxysterols (7 alpha- and 7 beta -hydroxychole sterol, 7 alpha -OH, and 7 beta -OH) and 3 beta -hydroxycholest-5-en-7-one (7-keto) in the brains of rats that underwent either a sham operation (cont rol), hypoxia, or CO inhalation (1005 ppm) at 37 degreesC for 90 min follow ed by 48 h of recovery. The levels of 7-hydroperoxycholesterols, 7 beta -OH , and 7-keto were low in the hypoxia group, while the levels were unaltered in the CO group compared with the controls. Among the three groups of CO i nhalation, these levels were high in the hyperthermia group (39 degreesC), and the 7-hydroperoxycholesterols were low in the hypothermia group (32 deg reesC), compared with the control group. The blood O-2 saturation was almos t normal in the hypothermia group, while it was similarly low in the hypert hermia and normothermia groups. The temperature-dependent lipid peroxidatio n in the brain after CO inhalation and recovery can not be explained by hyp oxia due to CO-hemoglobin formation, but may contribute to the delayed neur onal death following CO inhalation. Hypothermia may be applicable to treat patients after CO inhalation. (C) 2001 Elsevier Science Inc.