Effects of Chronic Exposure to Ultrasound of Alternating Frequencies on the Levels of Aggression and Anxiety in CBA and BALB/c mice

Abstract

Stress-induced changes in the behavior of CBA and BALB/c mice were studied after 3-week ultrasound exposure (22-45 kHz). The mice of both lines demonstrated increased aggression in the resident-intruder and social interest paradigms and reduced number of social interactions in the social interest test. Elevated plus maze test showed a decrease in anxiety level in CBA mice and an increase in this parameter in BALB/c mice. Chronic exposure to ultrasound induced an increase in aggression level in mice of both lines that was not directly related to changes in anxiety level.

Understanding the molecular mechanisms of aggression in BALB/c and TPH2-deficient mice

“…Mice were subjected to a 3-week exposure of ultrasound of unpredictably alternating frequencies (see below), and after behavioural testing, were additionally investigated for brain levels of oxidative stress markers, carbonyl protein and total glutathione, gene and protein expression of AMPA receptor subunits GluA1-4, 5-HT6 receptor, and protein expression of PSD95, PSA-NCAM and β-catenin using RT-PCR and Western blot (see below; Fig.1A). Subgroups of mice from the ultrasound-exposed group were treated with thiamine or benfotiamine at the dose of 200 mg/kg/day via drinking water, as described elsewhere (Markova et al, 2017;Pavlov et al, 2017). Mouse behavior was investigated twenty-four hours after the termination of ultrasound exposure in a novel cage, a social interaction test and in the forced swim test; they were killed sixteen hours after the behavioural testing, their brains were dissected (see below; Fig 1A).…”

“…This test was carried out as described previously (Malatynska et al, 2012;Strekalova et al, 2015;Pavlov et al, 2017). Mice were placed into a plastic transparent pool (diameter of 15 cm and a height of 25 cm) filled with water to the depth for 17 cm; water temperature was +23°C, light intensity was 15 Lux.…”

“…Quantitative real-time PCR was carried out as described elsewhere Pavlov et al, 2017). Briefly, 1 μg total RNA was converted into cDNA using random primers and Superscript III transcriptase (Invitrogen, Carlsbad, CA, USA).…”

“…The housekeeping gene glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was selected as the reference gene since previous experiments demonstrated relatively low variability in GAPDH expression in the limbic structures of the rodents exposed to the ultrasound exposure Pavlov et al, 2019). Data were normalized to GAPDH mRNA expression and calculated as relative-fold changes compared to control mice as described elsewhere Pavlov et al, 2017Pavlov et al, , 2019).…”

“…Heavy metal exposure is also known to induce aggression and amenable to therapy after exposure to toxic concentrations of lead (Ebuehi et al, 2012), and cadmium (El-Tarras et al, 2016). Thiamine (vitamin B1) and its derivatives are regulators of mitochondrial function and metabolism (Bettendorff et al, 2014) and are known to exert anti-oxidative and anti-stress effects in in vitro models (Schmid et al, 2008;Bozic et al, 2015;Raj et al, 2018) and in experimental models of stress (Markova et al, 2017;Pavlov et al, 2017), traumatic brain injury (Mkrtchyan et al, 2018) and neurodegeneration (Pan et al, 2010(Pan et al, , 2016Tapias et al, 2018). We have recently shown that a two-week pre-treatment regime in mice with thiamine, or its more bioavailable analogue benfotiamine can prevent increases in the GSK3-beta activity and measures of depressive-like and anxiety-like behavior following both predator stress and modified swim test paradigms (Markova et al, 2017;.…”