Neurobehavioral assessment following e-cigarette refill liquid exposure in adult rats

Abstract

The present study was conducted to assess the toxic effect of e-cigarette refill liquid on cognitive and motor functions in adult rats. Animals were administered 28 μl/kg of body weight of e-liquid with/without a dose of 0.5 mg of nicotine/kg of body weight, using the intraperitoneally route for a period of 4 weeks. They were then evaluated by novel object recognition test (NORT) and spontaneous alternation T-maze test for cognitive functions. Results indicated that e-liquid without nicotine induced, in the NORT, a decrease in time exploring the novel object during the test session and lower discrimination and recognition indexes compared to control and e-liquid with nicotine treated rats. Furthermore, short-term spatial memory was affected after e-liquid treatment in the spontaneous alternation T-maze test, identifying recognition memory impairments. However, none of the treatments altered motor functions assessed by inclined plane test, Kondziela’s inverted screen test and weights test. Cell cytotoxicity assessment following e-liquid exposure showed a significant decrease in hippocampal cell viability, but no change in cortical cell viability. Thereby, e-liquid without nicotine causes cognitive impairments, especially on the hippocampus. Based on these results, more extensive assessments on e-cigarettes must be carried out.

Keywords:

• Adult rat
• cognitive impairments
• e-liquid
• neurotoxicity

Disclosure statement

The authors declare that there are no conflicts of interest.

Funding information

Financial support of the Tunisian Ministry of Higher Education and Scientific Research is gratefully acknowledged. We appreciated the assistance of Abdelhamid Mselmi and Radhouen Ben Kram from the Tunis Faculty of Sciences during animal treatment period. We are extremely grateful to Olfa Masmoudi from the Tunis Faculty of Sciences for the preparation of cell suspensions from hippocampal and cortical tissues.