Chronic stress and its effects on adrenal cortex apoptosis in pregnant rats

The effects of chronic restraint stress on empathy-like behaviour in rats

It is clearly known that psychological stress is an important threat to health in today's modern societies. Recent studies have shown that acute stress causes an increase in positive social behaviours such as prosocial behaviour and devotion which are components of empathic behaviour. Neuropsychiatric manifestations such as anxiety and depression may affect empathic behaviour. The aim of this study was to investigate the effects of chronic restraint stress on empathy-like behaviour and the histopathological changes in the amygdala, prefrontal cortex in the adrenal glands and thymus, as well as the neurochemical pathways associated with empathy, oxytocin and vasopressin. The chronic stress group was subjected to restraint stress daily for 14 days after all subjects were trained to rescue its stressed cagemate using empathy test equipment for 12 days. It was observed that chronic restraint stress had no effect on empathy-like behaviour in rats. Vasopressin levels in amygdala was increased in chronic stress group compared to control group. Anxiety and depression indicators did not change in both groups. In the open field test, control group spent more time in thigmo zone compared to chronic stress group. Adrenal glands relative weights and apoptotic cell ratios were significantly higher in the chronic stress group compared to the control group (expectedly). Although there was no significant difference in behavioral tests, histopathological changes were detected. In subsequent studies, it is appropriate to examine the effects of different types of stress applications, gender-related changes, and other neurochemical pathways associated with stress and empathy.

Concentrate diet modulation of ruminal genes involved in cell proliferation and apoptosis is related to combined effects of short-chain fatty acid and pH in rumen of goats

Short-chain fatty acids (SCFA) regulate cell proliferation and cell apoptosis in gastrointestinal tissue in vitro and in vivo. We have tested the hypothesis that a medium-concentrate intake induces mRNA abundance alterations of genes involved in cell proliferation and cell apoptosis in the rumen epithelium of goats, and that these changes in mRNA abundance are related to ruminal SCFA concentration and ruminal pH. Goats (n=16) were randomly allocated to 2 groups and fed either a low-concentrate (LC) diet (10% concentrate; n=8) or a medium-concentrate (MC) diet (35% concentrate; n=8) in 2 equal portions daily. The individually housed goats were fed separately with their respective diet for 3wk and were slaughtered 6h after the morning feed on d 22. In vivo, goats receiving the MC treatment exhibited a greater ruminal SCFA concentration (73.7mM) compared with those receiving the LC treatment (53.2mM), and the pH decreased from 6.9 to 6.5. The expression of proliferative genes of cyclin A, cyclin B1, cyclin D1, cyclin E1, CDK1, CDK2, CDK4, and CDK6 mRNA in the MC group was enhanced. The gene expression of apoptosis genes (caspase 3, caspase 8, caspase 9, p53, and Bax) was significantly higher, and the ratio of Bcl-2 to Bax (Bcl-2/Bax) expression was lower in the MC group than in the LC group. The same trend was observed in the population of apoptotic cells analyzed by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay. The cell density in the stratum germinativum of the MC group was significantly increased compared with that in the LC group. During primary culture of rumen epithelial cells, SCFA or pH treatment alone of the culture medium had significant effects on the expression of most of the genes tested in the present study. Furthermore, SCFA and pH exerted combined effects on the expression of cyclin A, cyclin B1, cyclin E1, CDK6, p53, Bcl-2, and Bcl-2/Bax. Thus, the MC diet induces alteration of gene expression of the genes that regulate both cell proliferation and apoptosis. These genes are regulated by combined effect of ruminal SCFA and ruminal pH.