The Anti-Inflammatory Effect and Mucosal Barrier Protection of Clostridium butyricum RH2 in Ceftriaxone-Induced Intestinal Dysbacteriosis

Short-term exposure to antibiotics begets long-term disturbance in gut microbial metabolism and molecular ecological networks

BACKGROUND

Antibiotic exposure can occur in medical settings and from environmental sources. Long-term effects of brief antibiotic exposure in early life are largely unknown.

RESULTS

Post a short-term treatment by ceftriaxone to C57BL/6 mice in early life, a 14-month observation was performed using 16S rRNA gene-sequencing technique, metabolomics analysis, and metagenomics analysis on the effects of ceftriaxone exposure. Firstly, the results showed that antibiotic pre-treatment significantly disturbed gut microbial α and β diversities (P < 0.05). Both Chao1 indices and Shannon indices manifested recovery trends over time, but they didn't entirely recover to the baseline of control throughout the experiment. Secondly, antibiotic pre-treatment reduced the complexity of gut molecular ecological networks (MENs). Various network parameters were affected and manifested recovery trends over time with different degrees, such as nodes (P < 0.001, R2 = 0.6563), links (P < 0.01, R2 = 0.4543), number of modules (P = 0.0672, R2 = 0.2523), relative modularity (P = 0.6714, R2 = 0.0155), number of keystones (P = 0.1003, R2 = 0.2090), robustness_random (P = 0.79, R2 = 0.0063), and vulnerability (P = 0.0528, R2 = 0.28). The network parameters didn't entirely recover. Antibiotic exposure obviously reduced the number of key species in gut MENs. Interestingly, new keystones appeared during the recovery process of network complexity. Changes in network stability might be caused by variations in network complexity, which supports the ecological theory that complexity begets stability. Besides, the metabolism profiles of the antibiotic group and control were significantly different. Correlation analysis showed that antibiotic-induced differences in gut microbial metabolism were related to MEN changes. Antibiotic exposure also caused long-term effects on gut microbial functional networks in mice.

CONCLUSIONS

These results suggest that short-term antibiotic exposure in early life will cause long-term negative impacts on gut microbial diversity, MENs, and microbial metabolism. Therefore, great concern should be raised about children's brief exposure to antibiotics if the results observed in mice are applicable to humans. Video Abstract.

Immunoregulatory role of the gut microbiota in inflammatory depression

Inflammatory depression is a treatment-resistant subtype of depression. A causal role of the gut microbiota as a source of low-grade inflammation remains unclear. Here, as part of an observational trial, we first analyze the gut microbiota composition in the stool, inflammatory factors and short-chain fatty acids (SCFAs) in plasma, and inflammatory and permeability markers in the intestinal mucosa of patients with inflammatory depression (ChiCTR1900025175). Gut microbiota of patients with inflammatory depression exhibits higher Bacteroides and lower Clostridium, with an increase in SCFA-producing species with abnormal butanoate metabolism. We then perform fecal microbiota transplantation (FMT) and probiotic supplementation in animal experiments to determine the causal role of the gut microbiota in inflammatory depression. After FMT, the gut microbiota of the inflammatory depression group shows increased peripheral and central inflammatory factors and intestinal mucosal permeability in recipient mice with depressive and anxiety-like behaviors. Clostridium butyricum administration normalizes the gut microbiota, decreases inflammatory factors, and displays antidepressant-like effects in a mouse model of inflammatory depression. These findings suggest that inflammatory processes derived from the gut microbiota can be involved in neuroinflammation of inflammatory depression.

Tumorigenesis in Inflammatory Bowel Disease: Microbiota-Environment Interconnections

Colo-rectal cancer (CRC) is undoubtedly one of the most severe complications of inflammatory bowel diseases (IBD). While sporadic CRC develops from a typical adenoma-carcinoma sequence, IBD-related CRC follows different and less understood pathways and its pathophysiological mechanisms were not completely elucidated. In contrast to chronic inflammation, which is nowadays a well-recognised drive towards neoplastic transformation in IBD, only recently was gut microbiota demonstrated to interfere with both inflammation processes and immune-mediated anticancer surveillance. Moreover, the role of microbiota appears particularly complex and intriguing when also considering its multifaceted interactions with multiple environmental stimuli, notably chronic pathologies such as diabetes and obesity, lifestyle (diet, smoking) and vitamin intake. In this review, we presented a comprehensive overview on current evidence of the influence of gut microbiota on IBD-related CRC, in particular its mutual interconnections with the environment.

Clostridium butyricum and Its Culture Supernatant Alleviate the Escherichia coli-Induced Endometritis in Mice

Endometritis is a disease with a high incidence in dairy cows and causes great economic loss to milk production. This study examined the therapeutic effects of Clostridium butyricum and its culture supernatant on Escherichia coli-induced endometritis in mice. The results showed that Clostridium butyricum and its culture supernatant effectively suppressed inflammatory responses of uterine tissues, such as uterine morphological changes, pathological damage, and the production of inflammatory cytokines. Clostridium butyricum and its culture supernatant significantly decreased uterine microbial loads. In addition, Clostridium butyricum and its culture supernatant restored reproduction outcomes in Escherichia coli-induced endometritis mice. Western blot analysis showed that Clostridium butyricum and its culture supernatant suppressed the NF-κB signaling pathway. Therefore, the anti-inflammatory mechanism of Clostridium butyricum and its culture supernatant may occur through the anti-bacterial activity and regulation of the expression of NF-κB in the uterus. The anti-inflammatory effect of the culture supernatant of C. butyricum was slightly better than that of viable C. butyricum. Therefore, our experimental results showed that Clostridium butyricum culture supernatant may be an effective drug for treating endometritis.

Octenyl Succinic Anhydride-Modified Starch Attenuates Body Weight Gain and Changes Intestinal Environment of High-Fat Diet-Fed Mice

Effects of octenylsuccinate (OS) starch on body composition and intestinal environment in high-fat diet-fed mice were investigated. C57BL/6J mice were treated with a regular-fat (RF) diet, a high-fat (HF) diet, or a high-fat diet supplemented with OS starch (HFOSS). Fecal short-chain fatty acids (SCFAs) were quantified using gas chromatography, and the fecal microbiota profile was analyzed by 16S rDNA sequencing. One-way ANOVA and metastats analysis were performed for statistical analysis. After 22 weeks of feeding, mice in the HFOSS group had significantly lower body weight, body fat, liver weight, and cumulative food intake than those in the HF group but higher than that of the RF group. Fecal total SCFA, acetic, propionic, and butyric acid concentrations were significantly higher in the HFOSS group than that in the HF and RF groups. OS starch intervention increased the relative abundance of Parabacteroides, Alistipes, and Ruminiclostridium_5 and decreased that of Tyzzerella, Oscillibacter, Desulfovibrio, and Anaerotruncus compared with the RF and HF groups. The relative abundance of Lachnospiraceae_UCG-006 in the HFOSS group was lower than that in the HF group but higher than that in the RF group. In conclusion, OS starch prevents fat accumulation in high-fat diet-fed mice and might provide potential health benefits due to its fermentability in the gut and its ability to regulate gut microbial community structure.

Clostridium butyricum RH2 Alleviates Chronic Foot Shock Stress-Induced Behavioral Deficits in Rats via PAI-1

Recent investigations have demonstrated that the chronic stress-induced behavioral disorders can be ameliorated by probiotics including Clostridium butyricum (C. butyricum) via the gut-brain-axis. However, the molecular mechanisms underlying the beneficial effects of C. butyricum on brain remain largely unknown. Here, we investigated whether chronic foot shock stress (CFSS) paradigm used for a hypertensive animal model could induce mood disorders such as anxiety, depression and cognitive impairments. Then, we assessed the impact of C. butyricum RH2 on the behavior disorders and neurobiological alterations in the hippocampus. Male Sprague-Dawley (SD) rats received intermittent electric shocks for consecutive 14 days and were treated with C. butyricum RH2 for 17 days. Anxiety- or depression-like behaviors were evaluated by open field test (OFT), and elevated plus maze (EPM). The Morris water maze test (MWM) was used to evaluate the cognitive functions. CFSS intervention led to mild anxiety- or depression-like behavior or cognitive impairment and C. butyricum RH2 treatment reversed the CFSS-induced symptoms. The serum ACTH or CORT was increased following CFSS but was completely reversed by C. butyricum RH2 treatment. In the hippocampus of CFSS rats, the expressions of BDNF and TrkB were downregulated but proBDNF and P75^NTR were upregulated. These expression changes were partially reversed by C. butyricum RH2, suggesting a mode of action on BDNF and proBDNF balance. CFSS exposure resulted in downregulation of tissue-type plasminogen activator (tPA) but upregulation of plasminogen activator inhibitor 1(PAI-1), which could contribute to the decrease in BDNF by reduced conversion from proBDNF to BDNF in the hippocampus. C. butyricum RH2 treatment reversed the upregulated PAI-1 but not the downregulated tPA, which was in parallel with the amelioration of behavioral abnormalities, suggesting a novel tPA independent mechanism for PAI-1 action. Our results demonstrate for the first time that C. butyricum RH2 attenuates stress-induced behavior disorders via inhibiting the expression of brain PAI-1.

Trans-Anethole Alleviates Subclinical Necro-Haemorrhagic Enteritis-Induced Intestinal Barrier Dysfunction and Intestinal Inflammation in Broilers

This study investigated the alleviative potential of trans-anethole (TA) on the impaired intestinal barrier and intestinal inflammation and its regulatory effects on gut microbiota in broilers with subclinical necro-hemorrhagic enteritis (NE) challenge. Subclinical NE challenge led to a severe decline in the 21-day body weight (BW) and average daily gain (ADG), but an increase in feed conversion ratio (FCR) and intestinal lesion score of birds compared with controls (P < 0.05). Compared with the subclinical NE group, the TA administration group exhibited lower (P < 0.05) intestinal lesion score and crypt depth (CD), serum diamine oxidase activity, and D-lactate concentration, but higher (P < 0.05) intestinal tight junction protein expressions, villus height (VH), VH/CD, and numbers of proliferating cell nuclear antigen (PCNA)-positive cells. The administration of TA also inhibited (P < 0.05) the expression of intestinal pro-inflammatory cytokines including interleukin (IL)-1β, IL-8, interferon-gamma (IFN-γ), and tumor necrosis factor-alpha (TNF-α) but increased (P < 0.05) jejunal IL-10 and secretory immunoglobulin A (sIgA) concentration. TA inclusion also led to a remarkable reduction of intestinal NF-kappa-B inhibitor alpha (IκBα) degradation and nuclear factor kappa beta (NF-κB) translocation. Moreover, TA modulated the cecal microbiota abundance and diversity of NE birds, as confirmed by reducing the phylum Firmicutes and genera Ruminococcaceae_UCG-014, Eubacterium_coprostanoligenes_group, and Ruminococcaceae_NK4A214_group when supplemented at 600 mg/kg and reducing genera Butyricicoccus, Oscillibacter, and Flavonifractor when supplemented at 400 mg/kg (P < 0.05). Supplementation of TA in broiler diets could alleviate subclinical NE infection by restoring intestinal barrier integrity, inhibiting NF-κB signaling pathway, and modulating gut microbiota. A 600-mg/kg dose of TA is the optimum concentration for ameliorating subclinical NE in broilers.

Probiotic fermentation of Ganoderma lucidum fruiting body extracts promoted its immunostimulatory activity in mice with dexamethasone-induced immunosuppression

Ganoderma lucidum is a legendary traditional Chinese medicine with various bioactivities. This study was conducted (a) to explore the in vitro fermentation of the water extracts of G. lucidum fruiting body with Lactobacillus acidophilus and Bifidobacterium breve and (b) to investigate the effect of fermentation broth (GLFB) on dexamethasone (DEX)-induced immunosuppressed mice. Our results demonstrated that probiotic fermentation of G. lucidum fruiting body extracts underwent structural changing of major ganoderic acid components, such as ganoderic acid A (GA) into GC2, and this fermentation process involves changing of several metabolic pathways in the probiotic strains. GLFB could significantly improve the immunity, intestinal integrity, and gut microbiota dysbiosis in DEX-treated mice, and the immunostimulatory activity of GLFB was found closely related to its direct regulation on the expansion of CD4⁺ T cells in Peyer's patches of mice. These data implied that probiotic fermentation of G. lucidum fruiting body extracts promoted its immunostimulatory activity via biotransformation of components such as GA. This research provides a theoretical support for the development and application of G. lucidum fermentation by probiotics.