Lactobacillus johnsonii BS15 Prevents Psychological Stress–Induced Memory Dysfunction in Mice by Modulating the Gut–Brain Axis

Abstract

Researchers are attempting to harness the advantages of the gut–brain axis to prevent neurocognitive disorders by enhancing intestinal health. In this study, four groups of ICR mice were orally gavaged with either phosphate-buffered saline (control and CW groups) or the probiotic strain Lactobacillus johnsonii BS15 (P and PW group; daily amounts of 2 × 10 8 colony-forming units) for 28 days. From days 22 to 28, the mice in the CW and PW groups were subjected to water-avoidance stress (WAS). The issue of whether psychological stress–induced memory dysfunction can be prevented via L. johnsonii BS15 pretreatment to modulate the gut–brain axis was investigated. Results show that L. johnsonii BS15 enhanced gut development by increasing villus height in the jejunum and ileum as well as villus height:crypt depth ratio in the ileum. L. johnsonii BS15 increased the activities of digestive enzymes, including trypsin and lipase in the jejunum and ileum. The intestinal goblet cell number was also increased by L. johnsonii BS15 pretreatment. Moreover, L. johnsonii BS15 balanced the gut microbiota by increasing the log 10 DNA gene copies of Lactobacillus spp. and L. johnsonii and decreasing that of Enterobacteriaceae in the cecum. L. johnsonii BS15 also exerted preventive effects on intestinal permeability WAS by modulating diamine oxidase and D -lactate levels in the serum and mRNA expression levels of the tight junction proteins claudin-1, occludin, and ZO-1 in the jejunum and ileum. L. johnsonii BS15 pretreatment modulated inflammatory factors, specifically tumor necrosis factor-alpha, interferon-gamma, and interleukin-10. L. johnsonii BS15 pretreatment improved their performance in two behavioral tests, namely the novel object and T-maze tests. This result indicates that psychological stress–induced memory dysfunction possibly could be prevented through the gut–brain axis. In addition, L. johnsonii BS15 exerted beneficial effects on the hippocampus by modulating memory-related functional proteins, especially those related to synaptic plasticity, such as brain-derived neurotrophic factor and stem cell factor. Moreover, L. johnsonii BS15 recovered antioxidant capacity and exerted protective effects on mitochondrion-mediated apoptosis in the hippocampus. Collectively, the modulation of the gut–brain axis by L. johnsonii BS15 could be considered a promising non-invasive treatment modality for psychological stress–induced memory dysfunction.

Fecal microbiota transplantation derived from Alzheimer’s disease mice worsens brain trauma outcomes in wild-type controls

“…The impact of the gut microbiome can extend past neurological conditions to capacity and behavioral outcomes. Specifically, a recent study showed that FMT rescued bacterial and behavioral changes after TBI (Wang et al, 2020). As expected, we found that the microbiota of AD mice transplanted into young mice after TBI produced motor deficits (Figure 3d).…”

“…Our current results show a trend wherein the levels of Lactobacillus johnsonii are decreased in FMT-AD animals compared to their FMT-young counterparts (Figure 2c). These results are further supported by a recent study that shows probiotics increased various Lactobacillus, including specifically the Lactobacillus johnsonii species, which prevented intestinal permeability, modulated proinflammatory factors, and correlated with better behavioral results (Wang et al, 2020). Other studies have shown that probiotics may increase the gut microbiome diversity and increase the abundance of Bacteroides and Faecalibacterium (Liu et al, 2020a).…”

Probiotics and their Metabolites Reduce Oxidative Stress in Middle-Aged Mice

“…4 c). Several beneficial functions of L. johnsonii have been reported, including thickened mucous membranes in stomach ulcers [ 30 ], restored numbers of serum IgA, IgG, and CD8 + cells, increased splenocyte counts in aged mice with protein–energy malnutrition [ 31 ], decreased glucagon and glucose levels in diabetic rats [ 32 ], and prevention of memory dysfunction [ 33 ]. The proportion of gut Akkermansia was also significantly elevated, to 0.41%, in mice receiving probiotics (high-dose) plus postbiotics, whereas in the 16-month-old mice it was only 0.04% (Fig.…”

Melatonin as Immune Potentiator for Enhancing Subunit Vaccine Efficacy against Bovine Viral Diarrhea Virus

“…The Ct values normalized with β-actin were used to calculate the mRNA-expression levels of brain-derived neurotrophic factor (BDNF), cyclic amp response element-binding protein (CREB), and the stem cell factor (SCF). Primers used in the RT-qPCR reactions were previously described [ 37 ] and are shown in Table 2 .…”