Heat-inactivated Lacticaseibacillus paracasei N1115 alleviates the damage due to brain function caused by long-term antibiotic cocktail exposure in mice.

Critical development period of intestinal microbiota occurs concurrently with brain development, and their interaction is influenced by the microbiota-gut-brain axis. This study examined how antibiotics exposure affected gut microbiota and brain development and analyzed the possible benefits of heat-inactivated Lacticaseibacillus paracasei N1115 (N1115). Thirty neonatal male mice were randomly divided into three groups and treated with sterilized water (control), an antibiotic cocktail (Abx), or antibiotics plus heat-inactivated N1115 (Abx + N1115) for 84 days. We found that while the mRNA levels of GABAAα1, GABAb1, and glucocorticoid receptor (GR) in the hippocampus and brain-derived neurotrophic factor (BDNF), GABAAα1, GABAb1, and nerve growth factor (NGF) in the prefrontal cortex were higher, the mRNA levels of 5-HT1A were lower in the Abx group. The Abx + N1115 group had lower mRNA levels of GABAAα1, GABAb1, and GR in the hippocampus and BDNF, GABAb1, and NGF in the prefrontal cortex than the Abx group. The latency period was longer in the Morris water maze test while longer rest time was seen in tail suspension test in the Abx group than the control and Abx + N1115 groups. In the open field test, the moving time and distance of the Abx group were reduced. Further, the alpha-diversity indexes of the Abx and Abx + N1115 groups were significantly lower than the control. Further, long-term exposure to antibiotics disrupted the intestinal microbiota as evidenced by decreased Bacteroides, Firmicutes, and Lactobacillus, and increased Proteobacteria and Citrobacter. However, N1115 significantly decreased the abundance of Citrobacter when compared with those in the Abx group. These results indicate that antibiotics can substantially damage the intestinal microbiota and cognitive function, causing anxiety and depression, which can be alleviated by heat-inactivated N1115 via modulation of the microbiota-gut-brain axis.

Streptococcus thermophilus MN-ZLW-002 Can Inhibit Pre-adipocyte Differentiation through Macrophage Activation.

It is well documented that obesity and metabolic syndrome have a deep association with the intestinal immune system of the host animal. Recent studies indicate that some selected probiotics can modulate the immune responses of the host animal, thereby altering its lipid metabolism. However, the underlying mechanisms are still not fully understood. This study was conducted to investigate the possibility of probiotics to activate macrophages in the hosts, thus alter the differentiation of pre-adipocytes. In this study, Streptococcus thermophilus MN-ZLW-002 (MN-ZLW-002) was co-cultured with RAW264.7 macrophages, with Lactobacillus rhamnosus GG (LGG) as a control. The conditioned medium (CM) of the co-culture was collected and then added to 3T3-L1 pre-adipocytes. Viable and heat-killed (80 °C, 30 min) MN-ZLW-002 stimulated RAW264.7 cells to produce significant amounts of interleukin (IL)-6 and tumor necrosis factor (TNF)-α and induced intense phosphorylation of P38, p44/42 mitogen-activated protein kinase (MAPK) (extracellular signal-regulated kinase (ERK)) and nuclear factor κB (NF-κB). Cytokine production reduced dramatically when heat-killed MN-ZLW-002 was treated with Ribonuclease. Viable and heat-killed LGG induced less cytokine production and little signaling protein activation. Viable and heat-killed MN-ZLW-002-stimulated RAW264.7-CM notably suppressed pre-adipocytes differentiation. However, viable LGG-stimulated RAW264.7-CM had a weaker effect and heat-killed LGG-stimulated RAW264.7-CM had no effect. These findings suggest that viable and heat-killed (80 °C, 30 min) MN-ZLW-002 may alter its lipid metabolism by regulating its immune response, possibly via the release of cytokine, particularly TNF-α. The RNA of heat-killed MN-ZLW-002 may be a key component in its immune activation effect.

Lactobacilli and bifidobacteria derived from infant intestines may activate macrophages and lead to different IL-10 secretion.

In this study, three strains of lactobacilli and bifidobacteria originally isolated from healthy infants, were tested for their abilities to activate RAW264.7 cells. Gene expression and cytokine production of interleukin-10 (IL-10) of RAW264.7 cells were evaluated. The activation of extracellular regulated protein kinases 1/2 (ERK1/2), p38, and nuclear factor-κB (NK-κB) were also assessed. These results suggest lactobacilli and bifidobacteria in infants may promote production of IL-10 in macrophages, conferring a protective effect in hosts suffering from inflammation. Dimerization of TLR2 and MyD88 and subsequent phosphorylation of the key downstream signaling molecules, such as MAPKs and NK-κB, may be one of the key underlying mechanisms of activation of macrophages by these microbes. Bifidobacteria and lactobacilli induced macrophages to secrete IL-10 in a different manner, which may relate to their abilities to activate key signaling pathways mediated by TLR2 and MyD88.

Antibiotics can cause weight loss by impairing gut microbiota in mice and the potent benefits of lactobacilli.

This study assessed whether antibiotics could alter gut microbiota to affect host growth and the possibility of alleviation by lactobacilli. We divided four-week-old BABL/c mice into control (Ctrl), antibiotic exposure (Abx), Lactobacillus plantarum PC-170 (PC), and Lactobacillus rhamnosus GG (LGG) group and the Abx, LGG, and PC group received an one-week antibiotic/antibiotic + probiotic treatment. The fecal microbiota and the expression of splenic cytokines were determined. Following the ceftriaxone treatment, the body weight gain of Abx was delayed compared with others. The ceftriaxone treatment significantly decreased the alpha-diversity of the fecal microbiota and altered the fecal microbiota but LGG and PC can partly alleviate the effect. At the end of the study, the microbial community of LGG and PC group were more similar to Ctrl compared with Abx group. The results indicated that ceftriaxone could significantly alter intestinal microbiota. Lactobacilli might alleviate the side effects of antibiotics by stabilizing the intestinal microbiota.

[Alleviation and recovery effects of Lactobacillus on the antibiotic-induced intestinal dysbiosis in early life stages of mice].

OBJECTIVE: To investigate the effects of Lactobacillus on the alleviation and recovery of ceftriaxone-induced intestinal dysbiosis in early life stages of mice, and the possible effect on immunity of the host. METHODS: A total of 48 four-week-old Balb/c male mice were randomly divided into four groups, with 12 in each group. The experiment lasted for four weeks. In the first week, mice were given normal saline, ceftriaxone, ceftriaxone plus Lactobacillus rhamnosus GG, ceftriaxone plus direct vat set pickle(PC) by gavage respectively in the control group(ctrl), ceftriaxone group(ceftri), PC group and LGG group. The PC group and LGG group were given PC and LGG respectively for the last three weeks. The feces were collected once a week, and the profile composition of fecal bacteria were analyzed by next-generation sequencing. The mRNA expression levels of interleukin-6(IL-6), IL-12 and tumor necrosis factor α(TNF-α) in the spleen were analysed using quantitative real-time PCR. RESULTS: In the first week, the simpson index decreased significantly in the ceftri group(P<0. 001), but not in PC and LGG groups. At week four, the observed-species index in the PC group increased significantly(P<0. 001) and the simpson index increased in both LGG group and ceftri group(P<0. 01). As for the flora structure, in the first week, the ctrl group differed from the other three groups significantly(P<0. 05) while no differences were found between the PC group and the LGG group. The firmicutes/bacteroides(F/B) ratio of three ceftriaxone-treated groups increased while the abundance of Akkermansia decreased, particularly in the ceftri group. In the fourth week, the intestinal flora structure were different between four groups(P<0. 05) and the F/B ratio and Akkermansia abundance recovered. Ruminococcaceae, Bacteroidaceae and Tannerellacea appeared in the ceftri group, while Lactobacillus was dominant in the PC group, and Akkermansia was the characteristic species of the LGG group. Weight lost was found in ceftriaxone-treated groups(P<0. 05) and the PC group recovered first. IL-12 and TNF-α mRNA expression of the spleen were lower in PC and LGG groups compared with the ceftri group(P<0. 01). IL-6 mRNA expression level in the LGG group were lower than the ctrl group(P<0. 01). CONCLUSION: The administration of antibiotics in the early life stage might inhibit weight gain, reduce the diversity of intestinal flora, damage functional bacteria and cause long-term inflammation, even though self-recovery ability exist. Lactobacillus might be helpful to alleviate the damage of antibiotics. But no therapeutic effect has been found.

Learning Stress, Involvement, Academic Concerns, and Mental Health among University Students during a Pandemic: Influence of Fear and Moderation of Self-Efficacy.

COVID-19 has had a profound impact on the mental health and well-being of students. An effective method that can enable students to cope with difficult times is to help them realize their inner potential. Following the stimulus-organism-response model, this study developed a theoretical framework that deepens our understanding of an environmental stimulus (fear of COVID-19) that is experienced by students; struggle within the organism (learning stress, learning involvement, and academic concerns); and the psychological response (psychological well-being). The findings clarified how the fear of COVID-19 affects the psychological well-being of university students and revealed the moderate role of academic self-efficacy in this process. Some systematic practical advice was provided to higher education institutions to develop effective interventions to protect the mental health of college students and establish strategies to promote their inner potential.

Influence of high-fat diet on host animal health via bile acid metabolism and benefits of oral-fed Streptococcus thermophilus MN-ZLW-002.

In this study, C57BL/6J male mice were fed normal chow (NC; control) or a high-fat diet (HFD) for 12 weeks, and HFD mice were supplemented with oral administration of Streptococcus thermophilus MN-ZLW-002 (HFD + MN002); n=20/group. Body weight, visceral fat, blood glucose, blood lipids and liver lipid deposition increased in the HFD group, and the composition of gut microbiota, cecum short-chain fatty acids and fecal bile acids (BAs) also changed. Oral-fed MN-002 increased the relative abundances of Ruminococcaceae, Lachnospiraceae and Streptococcaceae and improved blood glucose, liver cholesterol deposition, and serum IL-10, CCL-3 and the fecal BAs composition. In conclusion, the high-fat diet changed the composition of bile acids by shaping the gut microbiota into an obese type, leading to metabolic disturbances. Streptococcus thermophilus MN-ZLW-002 regulated gut microbiota by adjusting the composition of bile acids and improved the perturbation caused by high-fat diets. However, the effect of MN002 observed in animal experiments needs to be verified by long-term clinical trials.

Potential Health-Promoting Effects of Two Candidate Probiotics Isolated from Infant Feces Using an Immune-Based Screening Strategy.

Commensal microorganisms in the human gut are a good source of candidate probiotics, particularly those with immunomodulatory effects that may improve health outcomes by regulating interactions between the gut microbiome and distal organs. Previously, we used an immune-based screening strategy to select two potential probiotic strains from infant feces in China, Bifidobacterium breve 207-1 (207-1) and Lacticaseibacillus paracasei 207-27 (207-27). In this study, the in vitro immunological effects and potential in vivo general health benefits of these two strains were evaluated using Lacticaseibacillus rhamnosus GG (LGG) as the control. The results showed that 207-1 and 207-27 significantly and differentially modulated the cytokine profiles of primary splenic cells, while did not induce abnormal systemic immune responses in healthy mice. They also modulated the gut microbiota composition in a strain-dependent manner, thus decreasing Gram-negative bacteria and increasing health-promoting taxa and short-chain fatty acid levels, particularly butyric acid. Conclusively, 207-1 and 207-27 shaped a robust gut environment in healthy mice in a strain-specific manner. Their potential immunomodulatory effects and other elite properties will be further explored using animal models of disease and subsequent clinical trials. This immune-based screening strategy is promising in efficiently and economically identifying elite candidate probiotics.

A high-fat diet and high-fat and high-cholesterol diet may affect glucose and lipid metabolism differentially through gut microbiota in mice.

This study was conducted to investigate the effects of a high-fat diet (HFD) and high-fat and high-cholesterol diet (HFHCD) on glucose and lipid metabolism and on the intestinal microbiota of the host animal. A total of 30 four-week-old female C57BL/6 mice were randomly divided into three groups (n=10) and fed with a normal diet (ND), HFD, or HFHCD for 12 weeks, respectively. The HFD significantly increased body weight and visceral adipose accumulation and partly lowered oral glucose tolerance compared with the ND and HFHCD. The HFHCD increased liver weight, liver fat infiltration, liver triglycerides, and liver total cholesterol compared with the ND and HFD. Moreover, it increased serum high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and total cholesterol compared with the ND and HFD and upregulated alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase significantly. The HFHCD also significantly decreased the α-diversity of the fecal bacteria of the mice, to a greater extent than the HFD. The composition of fecal bacteria among the three groups was apparently different. Compared with the HFHCD-fed mice, the HFD-fed mice had more Oscillospira, Odoribacter, Bacteroides, and [Prevotella], but less [Ruminococcus] and Akkermansia. Cecal short-chain fatty acids were significantly decreased after the mice were fed the HFD or HFHCD for 12 weeks. Our findings indicate that an HFD and HFHCD can alter the glucose and lipid metabolism of the host animal differentially; modifications of intestinal microbiota and their metabolites may be an important underlying mechanism.