Cross-tolerance : Hyperthermia preconditioning induces ischemic tolerance in immature rat brain

Abstract

In an ischemia-hypoxia model (I-H) employing neonatal rats, preconditioning by whole-body hyperthermia or hypoxia was induced at 24 hours prior to I-H. The numbers of animals that developed ishemia were 79 of 23 rats in the control group, 4 of 21 in the hyperthermia group, and 0 of 8 in the hypoxia group. The proportions of the ischemic area that survived the ischemia in striatal and hippocampal coronal sections were 54.6 ± 5.2% and 49.3 ± 5.6%, 90.6 ± 4.8% and 92.5 ± 3.8%, and 100 ± 0% and 100 ± 0% in the three groups, respectively (mean ± SE). The stress of hyperthermia induced an ischemic tolerance phenomenon (cross tolerance) during subsequent I-H in the immature rat brain.