title: Further investigation of phenotypes and confounding factors of progressive ratio performance and feeding behavior in the BACHD rat model of Huntington disease.
abstract: Huntington disease is an inherited neurodegenerative disorder characterized by motor, cognitive, psychiatric and metabolic symptoms. We recently published a study describing that the BACHD rat model of HD shows an obesity phenotype, which might affect their motivation to perform food-based behavioral tests. Further, we argued that using a food restriction protocol based on matching BACHD and wild type rats' food consumption rates might resolve these motivational differences. In the current study, we followed up on these ideas in a longitudinal study of the rats' performance in a progressive ratio test. We also investigated the phenotype of reduced food consumption rate, which is typically seen in food-restricted BACHD rats, in greater detail. In line with our previous study, the BACHD rats were less motivated to perform the progressive ratio test compared to their wild type littermates, although the phenotype was no longer present when the rats' food consumption rates had been matched. However, video analysis of food consumption tests suggested that the reduced consumption rate found in the BACHD rats was not entirely based on differences in hunger, but likely involved motoric impairments. Thus, restriction protocols based on food consumption rates are not appropriate when working with BACHD rats. As an alternative, we suggest that studies where BACHD rats are used should investigate how the readouts of interest are affected by motivational differences, and use appropriate control tests to avoid misleading results. In addition, we show that BACHD rats display distinct behavioral changes in their progressive ratio performance, which might be indicative of striatal dysfunction.
authors.affiliation: Institute of Medical Genetics and Applied Genomics, Tuebingen, Tuebingen, Germany.|Centre for Rare Diseases, Tuebingen, Tuebingen, Germany.
authors.forename: Erik Karl Håkan
authors.identifier: 0000-0002-5158-6924
authors.initials: EK
authors.lastname: Clemensson
authors.affiliation: Institute of Medical Genetics and Applied Genomics, Tuebingen, Tuebingen, Germany.|Centre for Rare Diseases, Tuebingen, Tuebingen, Germany.|QPS Austria, Grambach, Austria.
authors.forename: Laura Emily
authors.initials: LE
authors.lastname: Clemensson
authors.affiliation: QPS Austria, Grambach, Austria.
authors.forename: Benedikt
authors.initials: B
authors.lastname: Fabry
authors.affiliation: QPS Austria, Grambach, Austria.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Flunkert
authors.affiliation: Institute of Medical Genetics and Applied Genomics, Tuebingen, Tuebingen, Germany.|Centre for Rare Diseases, Tuebingen, Tuebingen, Germany.
authors.forename: Olaf
authors.initials: O
authors.lastname: Riess
authors.affiliation: QPS Austria, Grambach, Austria.
authors.forename: Robert
authors.initials: R
authors.lastname: Wronski
authors.affiliation: Institute of Medical Genetics and Applied Genomics, Tuebingen, Tuebingen, Germany.|Centre for Rare Diseases, Tuebingen, Tuebingen, Germany.
authors.forename: Huu Phuc
authors.initials: HP
authors.lastname: Nguyen
mesh_terms: D000704:Analysis of Variance; D000821:Animal Feed; D000818:Animals; D001522:Behavior, Animal; D015415:Biomarkers; D001823:Body Composition; D004195:Disease Models, Animal; D018450:Disease Progression; D005247:Feeding Behavior; D006816:Huntington Disease / Q000097:blood / Q000378:metabolism / Q000473:pathology*; D020738:Leptin / Q000097:blood / Q000378:metabolism; D008297:Male; D010641:Phenotype; D051381:Rats
chemical_list: D015415:Biomarkers; D020738:Leptin