Sex differences and similarities in depressive- and anxiety-like behaviour in the Wistar-Kyoto rat

Abstract

Depression is a debilitating psychiatric disorder that is highly comorbid with anxiety. Depression is twice as prevalent in women as in men, however, females remain underrepresented in preclinical research. The stress hyperresponsive Wistar-Kyoto (WKY) rat displays hypolocomotion in a novel aversive environment and depressive- and anxiety-like behaviours, which have been mostly characterised in males. The current study characterised behaviour in male and female rats in a battery of behavioural paradigms. Adult male and female WKY rats were tested in the open field and forced swim tests (tests with a locomotor component); and the marble burying, novelty-induced hypophagia and sucrose preference tests (tests with a minimal locomotor component) and 24h home-cage locomotor activity was also monitored. The tests were compared against the Sprague-Dawley (SD) strain, a commonly used "control" strain. SD, but not WKY, females exhibited higher home-cage locomotor activity compared to males. In the open field, WKY rats of both sexes exhibited a significant reduction in locomotor activity and increased anxiety-like behaviour as demonstrated by reduced time in the aversive inner zone of the open field, compared to SD counterparts. In the marble burying test, WKY females, but not males, exhibited a trend towards increased burying, indicative of anxiety-like/neophobic behaviour. In comparison, WKY males, but not females, exhibited enhanced novelty-induced hypophagia, indicative of increased anxiety-like behaviour compared to SD rats. In the forced swim test, WKY rats of both sexes spent more time immobile compared with SD counterparts, indicating depressive-like behaviour. However, in comparison to SD rats, WKY males, but not females, exhibited anhedonic-like behaviour. In conclusion, WKY rats exhibit depressive- and anxiety-like behaviours that are complex and nuanced depending on the sex of the rat and testing conditions. This study supports the use of a varied test battery to fully characterise depression/anxiety-like behaviour in male and female rats.

Chronic intermittent ethanol exposure leads to alterations in brain-derived neurotrophic factor within the frontal cortex and impaired behavioral flexibility in both adolescent and adult rats

“…Previous studies have shown a correlation between decreased activity (total distance travelled and arm entries) and anxiety-like behavior (center time and open arm time) on both open field and elevated plus maze behavior across rodent species (Walf and Frye, 2007; Bailey and Crawley, 2009; Moore et al, 2011; Burke et al, 2016). Other studies using traditional assessments of anxiety (open field, elevated plus maze, light-dark box) have shown that CIE increases anxiety-like behavior, where early adolescent EtOH exposure leads to decreased time spent in the light, open arms or center of a field (Pandey et al, 2006; Coleman et al, 2014; Sakharkar et al, 2016).…”

GHSR‐1 agonist sensitizes rat colonic intrinsic and extrinsic neurons to exendin‐4: A role in the manifestation of postprandial gastrointestinal symptoms in irritable bowel syndrome?

“…Anxiety‐ and depression‐like behaviors, including stress‐induced defecation and time spent in the aversive, exposed inner zone of the open‐field arena and behavior in the forced swim test are not reported to differ between male and female Sprague Dawley (SD) and Wistar Kyoto (WKY) rats . Moreover, both male and female WKY rats exhibit lower pain threshold to CRD as compared to SD rats.…”

“…Anxiety-and depression-like behaviors, including stress-induced defecation and time spent in the aversive, exposed inner zone of the open-field arena and behavior in the forced swim test are not reported to differ between male and female Sprague Dawley (SD) and Wistar Kyoto (WKY) rats. 27 Moreover, both male 28 and female 29 WKY rats exhibit lower pain threshold to CRD as compared to SD rats. Given the lack of sex difference and to avoid the cyclical hormonal changes, 8-to 12-week-old male SD and WKY rats, purchased from Envigo, Derbyshire, UK, were selected for this study.…”

A novel herbal treatment reduces depressive-like behaviors and increases brain-derived neurotrophic factor levels in the brain of type 2 diabetic rats

“…The LAT was used to evaluate depressive-like and anxiety-like behaviors13 as a complement to OFT. Each rat was placed in a black box (100×100×40 cm) without cover, which was enclosed in a soundproof box.…”