Biology subjects

Miletto Petrazzini, M. E.

Publications and source records attributed to Miletto Petrazzini, M. E..

2 recordsLinked to original sources

bioRxiv2020

Stress reactivity elicits a tissue-specific reduction in telomere length in ageing zebrafish (Danio rerio)

Telomere length reflects cellular ageing. Increased telomere shortening in leukocytes is associated with a range of neurodegenerative and cardiovascular diseases, the onset and progression of which may be mediated by behavioural traits such as anxiety and stress reactivity. However, the effects of the hypothalamus-pituitary-adrenal axis stress response are shown to be tissue specific. As such, leukocyte telomere length may not give an accurate measure of the relationship between stress-reactivity and telomere length in disease relevant tissues. To test the hypothesis that stress-reactivity contributes to age-related telomere shortening in a tissue specific manner, we examined the correlation between telomere length in heart and brain tissue and stress-reactivity in a population of young (6-9 month) and ageing (18 month) zebrafish. Stress-reactivity was assessed by tank diving, a zebrafish version of the rodent open-field test, and through gene expression. Telomere length was assessed using quantitative polymerase chain reaction. We show that ageing zebrafish have shorter telomeres in both heart and brain. Telomere length is inversely related to stress-reactivity in heart but not brain of ageing individuals. These data support the hypotheses that an anxious predisposition contributes to telomere shortening in heart tissue, and by extension age-related heart disease, and that stress-reactivity contributes to age-related telomere shortening in a tissue-specific manner.

physiology↗

bioRxiv2020

Moderate early-life stress improves adult zebrafish (Danio rerio) spatial short-term memory but does not affect social and anxiety-like responses

Early-life stress (ELS) is defined as a short or chronic period of trauma, environmental or social deprivation, which can affect different neurochemical and behavioral patterns during adulthood. Zebrafish (Danio rerio) have been widely used as a model system to understand human neurodevelopmental disorders and display translationally relevant behavioral and stress-regulating systems. In this study, we aimed to investigate the effects of moderate ELS by exposing young animals (six weeks post-fertilization), for three consecutive days, to three stressors, and analyzing the impact of this on adult zebrafish behavior (sixteen weeks post-fertilization). The ELS impact in adults was assessed though analysis of performance on tests of unconditioned memory (free movement pattern Y-maze test), exploratory and anxiety-related task (novel tank diving test) and social cohesion (shoaling test). Here, we show for the first time that moderate ELS increases the number of pure alternations compared to pure repetitions in the unconditioned Y-maze task, suggesting increased spatial short-term memory, but has no effect on shoal cohesion, locomotor profile or anxiety-like behavior. Overall, our data suggest that moderate ELS may be linked to adaptive flexibility which contributes to build resilience in adult zebrafish by improving short-term spatial memory performance.

animal behavior and cognition↗