Exploring toothpaste ingredients as potential chemical kindling agents in neuropsychiatric disorders: An adult zebrafish (Danio rerio) study
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Published on: November 3, 2023
Thomas Mathew1, Shagun Bhardwaj1, Aditi Goyal1
1St. John's Medical College Hospital, Bengaluru, India.
Introduction:
Certain ingredients in toothpaste have the potential to cause headache disorders and seizures. Essential oils, particularly camphor and eucalyptus, may contribute to neuronal excitability. We hypothesize that toothpaste containing brain-stimulating substances may induce behavioral changes in zebrafish. The aim of this study was to investigate the neurobehavioral and histopathological effects of exposure to three commercially available toothpaste formulations in adult zebrafish (Danio rerio).
Methods:
We used four tanks, each containing 10 adult zebrafish, with one control and the three intervention tanks. 100 mg of three different toothpastes was added to the tanks for two weeks, after which the fish were observed for the next six weeks. The Mirror Biting Test and the Novel Tank Test were conducted at 4 weeks after intervention to assess aggression and anxiety, respectively. Python software was used to track the fish movements. Six weeks post intervention, histology and glial fibrillary acidic protein (GFAP) immunohistochemistry between the test groups were compared.
Results:
During the two-week screening phase prior to the addition of toothpaste, all the fish were healthy and exhibited normal activity. During the intervention, hyperactivity was observed in all intervention tanks compared to the control, especially in Tank 2, which contained a camphor-based toothpaste. The fish in the control tank moved at an average speed of 9.10 pixels/frame, while those in Tanks 1, 2, and 3 moved at 13.25 pixels/frame, 9.43 pixels/frame, and 9.94 pixels/frame, respectively. The Mirror Biting Test and the Novel Tank Test indicated increased aggression and anxiety in all intervention tanks, with the most notable effects observed in Tank 2. Histopathological examination revealed no neuronal alterations; however, an increase in GFAP expression was detected across all intervention groups.
Conclusions:
The findings of this study suggest that toothpaste ingredients can cause hyperactivity, aggression, anxiety and astrocytosis in adult zebra fish.
