title: The effects of neonatal cryoanaesthesia-induced hypothermia on adult emotional behaviour and stress markers in C57BL/6 mice.
abstract: Since the early 1930s, deep hypothermia (cryoanaesthesia) has been a useful anaesthetic in several types of surgery on neonatal rodents. Especially against the background of modern techniques in systems neuroscience, the method enjoys again increasing popularity. However, little is known about its effects on the subsequent adult behavioural and physiological profile. To systematically investigate the effects of neonatal cryoanaesthesia on adult basal and emotional behaviour as well as on physiological development, 59 C57BL/6 mouse pups were randomly assigned to one of three treatment groups: Pups of the first group were exposed to the hypothermia treatment (H) on postnatal day 3, while pups of the other two groups served as controls: These pups either remained in the home cage without any intervention (C), or were separated from the mother for 15 min (MS) to differentiate between effects of neonatal isolation alone versus hypothermia that inevitably goes along with neonatal isolation. Subsequent behavioural analyses were conducted during adulthood (P 84-P 130), including tests for exploratory, anxiety-like and depression-like behaviour. At the age of about 145 days mice were decapitated to record BDNF levels in the hippocampus and serum corticosterone. Altogether, H mice were found to display slightly increased anxiety levels on the O-Maze, but did not differ from the control animals in any other behavioural test. Subtle alterations in anxiety-like behaviour, however, were not accompanied by physiological changes in serum corticosterone and hippocampal BDNF levels, arguing against an overall long-lasting effect of neonatal hypothermia on the emotional profile of adult mice.
authors.affiliation: Research Group Animal Models in Psychiatry, Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, 68159 Mannheim, Germany. Electronic address: richterh@uni-muenster.de.
authors.forename: S Helene
authors.initials: SH
authors.lastname: Richter
authors.affiliation: Research Group Animal Models in Psychiatry, Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, 68159 Mannheim, Germany.
authors.forename: Eva
authors.initials: E
authors.lastname: Wollmann
authors.affiliation: Research Group Animal Models in Psychiatry, Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, 68159 Mannheim, Germany.
authors.forename: Michaela
authors.initials: M
authors.lastname: Schmidt
authors.affiliation: Research Group Animal Models in Psychiatry, Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, 68159 Mannheim, Germany.
authors.forename: Uwe
authors.initials: U
authors.lastname: Zillmann
authors.affiliation: Department of Psychiatry, Charité Campus Mitte, 10117 Berlin, Germany.
authors.forename: Rainer
authors.initials: R
authors.lastname: Hellweg
authors.affiliation: Department of Molecular Neurobiology, Max-Planck-Institute for Medical Research, 69120 Heidelberg, Germany.
authors.forename: Rolf
authors.initials: R
authors.lastname: Sprengel
authors.affiliation: Research Group Animal Models in Psychiatry, Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, 68159 Mannheim, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Gass
mesh_terms: D000375:Aging / Q000378:metabolism / Q000523:psychology*; D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development / Q000523:psychology; D001007:Anxiety; D015415:Biomarkers / Q000097:blood / Q000378:metabolism; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism*; D003345:Corticosterone / Q000097:blood*; D050785:Cryoanesthesia / Q000523:psychology*; D003863:Depression; D004644:Emotions / Q000187:drug effects*; D005106:Exploratory Behavior; D005260:Female; D006624:Hippocampus / Q000378:metabolism; D007036:Hypothermia, Induced / Q000379:methods / Q000523:psychology*; D008297:Male; D018782:Maze Learning; D051379:Mice; D008810:Mice, Inbred C57BL; D013315:Stress, Psychological
chemical_list: D015415:Biomarkers; D019208:Brain-Derived Neurotrophic Factor; D003345:Corticosterone
keywords: Anaesthesia; C57BL/6 mice; Cryoanaesthesia; Emotional behaviour; Home cage behaviour; Hypothermia; Neonatal mice; Serum corticosterone