Abstract

Huntington's disease (HD) is a neurodegenerative disease and is caused by an expanded trinucleotide repeat in the huntingtin gene. There are various animal models of HD which all mirror at least partially the behavioural and neuropathological phenotype of the human disease. Nevertheless, the results of the studies in HD animal models are inconsistent across laboratories because of the lack of standardised testing conditions and husbandry and the autotelic differences between the different lines. To avoid experimenter dependent effects in the behavioural evaluation of HD mice we have compared the YAC128 full length model (on a FVB/N background) and the Hdh Q111 knock-in mouse (on a C57Bl/6 background) with heterozygous HDHex4/5 knock-out mice using an automated home cage system at different ages. The Labmaster system measured automatically and in a standardised setting drinking, feeding and activity for a time period of 70 h. Therefore, it allows us to detect even subtle differences in circadian food and fluid consumption as well as locomotor activity with rearing behaviour. This is especially of importance in the ‘late onset’ full length models with a relatively mild and not rapidly progressive phenotype. Furthermore, it has been shown that expression levels of full length htt influence body weight in a dose dependent manner in YAC128, YAC18 and heterozygous Hdh knock-out mice.

Our study gives us the opportunity to carefully characterise the relationship between different levels of htt and activity and food intake in vivo. First results will be presented.