Behavioural effects of high fat diet in adult Nrg1 type III transgenic mice

Some diets appear to have detrimental effects on schizophrenia symptoms. Neuregulin 1 (NRG1) is a risk gene for schizophrenia and a recently developed transgenic mouse model for Nrg1 type III demonstrates a schizophrenia-relevant phenotype. The current study evaluated the behavioural response of Nrg1 type III transgenic mice to a high fat diet (HFD) to determine the potential interactive impact of diets and genetic risk factors on disease symptoms. Male and female Nrg1 III and control littermates (N = 13-24) were exposed during adulthood to either HFD or standard chow diet (CHOW) for eight weeks before being tested in behavioural domains relevant to schizophrenia. Locomotion and exploration, anxiety, social behaviours (including social preference), sensorimotor gating (i.e. prepulse inhibition, PPI), associative learning, and anhedonia were assessed. HFD increased the body weight gain of mice, suppressed locomotion, exploration, and anxiety-related behaviours in a sex-dependent manner. HFD augmented the PPI response in male mice and decreased anhedonia in a sucrose preference test. Finally, HFD had a sex-dependent impact on fear-associated memory with HFD-induced cognitive impairments being most prominent in Nrg1 transgenic females. In conclusion, HFD and mutant Nrg1 III interactively impair particular cognitive domains in a sex-specific manner. Thus, our preclinical data suggest that genetic predisposition to the schizophrenia risk gene NRG1 may modulate detrimental behavioural effects of diets. This indicates the importance to research further the role of particular diets in the context of populations at risk to develop schizophrenia.