Study on some behavioral and oxidative changes observed in zebrafish exposed to chronic stress.

Zebrafish (Danio rerio) are currently used for various biomedical and environmental studies. Due to the comprehensive ethological and genetical description, but also due to a significant similarity to humans, zebrafish are successfully used in modelling some traits associated with human pathology (both psychiatric and others) and determining the effects of environmental factors on behaviour and highly conserved molecular processes. Due to the fact that chronic exposure to stress is a major problem for contemporary society, any description of the phenomenon and finding solutions to minimize its harmful effects are important research directions. Therefore, through this study, we aimed to evaluate and describe some behavioural and oxidative changes that occur following exposure to chronic stress, in an adapted animal model. Twenty zebrafish were acclimatized to laboratory conditions and randomly divided into 2 study groups: a control group and a group that was exposed to a combination of stressors for 10 consecutive days. Following stress exposure, locomotor activity and affective state were assessed. Afterwards, biological samples were collected and used to determine some oxidative status parameters (the enzymatic activity of superoxide dismutase, of glutathione peroxidase, and the amount of malondialdehyde). We obtained significant variations of some behavioural parameters suggesting a significant harmful effect of chronic stress on the locomotor activity. Also, manifestations of anxious-depressive behaviours were observed, as compared to the control group. Biochemical analyses revealed significant changes in the activity of the antioxidant enzymes and increased lipid peroxidation which suggests that exposure to chronic stress could lead to the occurrence of oxidative stress. [ABSTRACT FROM AUTHOR]