Hyperthermic preconditioning prevents blood-brain barrier disruption produced by hypoxia-ischemia in newborn rat.
Effect of hyperthermic preconditioning on disruption of blood-brain barrier induced by hypoxic-ischemic insult was examined. Seven-day-old Wistar rats were separated into (1) pre-heated (15 min of hyperthermia at 41.5-42.0 degrees C) or (2) non-heated group (33 degrees C). Twenty-four hours after conditioning, all rats were subjected to 2 h hypoxia-ischemia (8% oxygen/92% nitrogen, at 33 degrees C), then 24 h later all brains were examined for immunohistological staining of endogenous macromolecule, IgG extravasation and staining of microtubule-associated protein 2 (MAP2) with MAP2 loss being an early marker of neuronal damage. Significant reduction in the area of IgG staining and loss of MAP2 staining was observed in the pre-heated group as compared to that in non-heated group. There was a close relationship between IgG staining and MAP2 staining loss, with the former area always found in the latter, suggesting that extravasation associates neuronal injury. Serum cortisol concentration in pre-heated group was significantly higher than that in non-heated group 24 h after hyperthermic treatment (14.8+/-0.6 vs. 12.5+/-0.3 ng/ml, p<0.01). These data indicate that hyperthermic preconditioning prevents disruption of blood-brain barrier, resulting in amelioration of hypoxic-ischemic neuronal damage in newborn rat.
Ikeda
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Department of Obstetrics and Gynecology, Miyazaki Medical College, 5200 Kihara, Kiyotake, Miyazaki, Japan. tikeda@post1.miyazaki-med.ac.jp
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Ikenoue
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D000818:Animals; D000831:Animals, Newborn / Q000502:physiology; D001812:Blood-Brain Barrier / Q000502:physiology*; D001921:Brain / Q000166:cytology / Q000378:metabolism / Q000473:pathology; D006358:Hot Temperature; D006854:Hydrocortisone / Q000097:blood; D006979:Hyperthermia, Induced; D020925:Hypoxia-Ischemia, Brain / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D007074:Immunoglobulin G / Q000032:analysis; D007150:Immunohistochemistry; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D009474:Neurons / Q000378:metabolism / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
D007074:Immunoglobulin G; D008869:Microtubule-Associated Proteins; D006854:Hydrocortisone