Hyperactivity in the Gunn rat model of neonatal jaundice: Age-related attenuation and emergence of gait deficits

Document Type

Article

Publication Date

1-1-2015

Identifier

DOI: 10.1038/pr.2014.199; PMCID: PMC4346430

Abstract

Copyright © 2015 International Pediatric Research Foundation, Inc.

Background:Neonatal jaundice resulting from elevated unconjugated bilirubin occurs in 60-80% of newborn infants. Although mild jaundice is generally considered harmless, little is known about its long-term consequences. Recent studies have linked mild bilirubin-induced neurological dysfunction (BIND) with a range of neurological syndromes, including attention-deficit hyperactivity disorder. The goal of this study was to measure BIND across the lifespan in the Gunn rat model of BIND.

Methods:Using a sensitive force plate actometer, we measured locomotor activity and gait in jaundiced (jj) Gunn rats versus their nonjaundiced (Nj) littermates. Data were analyzed for young adult (3-4 mo), early middle-aged (9-10 mo), and late middle-aged (17-20 mo) male rats.

Results:jj rats exhibited lower body weights at all ages and a hyperactivity that resolved at 17-20 mo of age. Increased propulsive force and gait velocity accompanied hyperactivity during locomotor bouts at 9-10 mo in jj rats. Stride length did not differ between the two groups at this age. Hyperactivity normalized, and gait deficits, including decreased stride length, propulsive force, and gait velocity, emerged in the 17-20-mo-old jj rats.

Conclusion:These results demonstrate that, in aging, hyperactivity decreases with the onset of gait deficits in the Gunn rat model of BIND.

Journal Title

Pediatric Research

Volume

77

Issue

3

First Page

434

Last Page

439

MeSH Keywords

Age Factors; Aniamls; Bilirubin; Gait Ataxia; Hyperkinesis; Neonatal Jaundice; Locomotion; Rats

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