BDNF expression in the hippocampus of maternally separated rats: does Bifidobacterium breve 6330 alter BDNF levels?

Abstract

Brain-derived neurotrophic factor (BDNF) is of interest because of its putative role in stress and psychiatric disorders. Maternal separation is used as an animal model of early-life stress and of irritable bowel syndrome (IBS). Animals exposed to the paradigm show altered gut function together with heightened levels of arousal and corticosterone. Some probiotic organisms have been shown to be of benefit in IBS and influence the brain-gut axis. Our objective was to investigate the effects of maternal separation on BDNF under basal conditions and in response to the probiotic Bifidobacterium breve 6330. The study implemented the maternal separation model which we have previously described. Polymerase chain reaction and in situ hybridisation were performed to measure the effect of maternal separation on both BDNF total variants and BDNF splice variant (exon) IV in the hippocampus. Maternally separated and non-separated rats were treated with B. breve 6330, to investigate the effect of this probiotic on BDNF total variant and BDNF exon IV expression. Maternal separation increased BDNF total variants (P<0.01), whilst having no effect on BDNF exon IV. B. breve 6330 increased BDNF total variants (P<0.01), and decreased BDNF splice variant IV, in non-separated rats (P<0.01). B. breve 6330 did not alter BDNF levels in the maternally separated rats. Maternal separation caused a marked increase in BDNF in the hippocampus. While B. breve 6330 influenced BDNF in normal animals, it had no significant effect on BDNF in those which were maternally separated. We have demonstrated that an orally administered probiotic can influence hippocampal BDNF.

Microbiota and host determinants of behavioural phenotype in maternally separated mice

“…Altered BDNF in the hippocampus and the amygdala has been previously associated with anxiolytic and antidepressant behaviour by us 26 and others 25,27 , but in the present study, we did not find a overall correlation between BDNF levels and mouse behaviour, except for the increased levels of hippocampal BDNF and decreased behavioural despair in MS GF male mice. Controversial results emerge from previous studies of hippocampal BDNF in SPF mice following MS: some reported higher [46][47][48] and others lower BDNF levels 9,49,50 in MS rodents. These controversies may thus represent a combined, and sometime opposing, effects of MS and gut microbiota on the brain and behaviour.…”

MicroRNA-132 may play a role in coexistence of depression and cardiovascular disease: A hypothesis

“…It is broadly accepted that stress triggers the activation of the HPA axis and causes the brain to be exposed to corticosteroids, affecting neurobehavioral functions with a strong down-regulation of hippocampal neurogenesis, and is a major risk factor for depression [18–20]. Chronic or severe stress and high-dose treatment with glucocorticoids decrease hippocampal synaptic plasticity and morphological neuroplasticity.…”

Bifidobacterium breve with α-Linolenic Acid and Linoleic Acid Alters Fatty Acid Metabolism in the Maternal Separation Model of Irritable Bowel Syndrome

“…It is clear that the strain is metabolically active in the GI tract, however, no increases in arachidonic acid and DHA were observed in the liver of NS rats fed B. breve DPC6330. Interestingly, we have previously seen that feeding B. breve DPC6330 to MS and NS rats elicited differing responses, however, in that case B. breve DPC6330 altered brain derived neurotrophic factor (BDNF) in the NS animals, with no effect in MS rats [52]. We suggested that the reason a response was not observed in MS rats following administration of B. breve DPC6330 was due to a ceiling effect for the biomarker and perhaps this is the same in relation to palmitoleic acid, arachidonic acid and DHA for NS rats fed B. breve DPC6330.…”