Photopolymerizable and Antibacterial Hydrogels Loaded with Metabolites from Lacticaseibacillus rhamnosus GG for Infected Wound Healing.

In response to increasing antibiotic resistance and the pressing demand for safer infected wound care, probiotics have emerged as promising bioactive agents. To address the challenges associated with the safe and efficient application of probiotics, this study successfully loaded metabolites from Lacticaseibacillus rhamnosus GG (LGG) into a gelatin cross-linked macromolecular network by an in situ blending and photopolymerization method. The obtained LM-GelMA possesses injectability and autonomous healing capabilities. Importantly, the incorporation of LGG metabolites endows LM-GelMA with excellent antibacterial properties against Staphylococcus aureus and Escherichia coli, while maintaining good biocompatibility. In vivo assessments revealed that LM-GelMA can accelerate wound healing by mitigating infections induced by pathogenic bacteria. This is accompanied by a reduction in the expression of key proinflammatory cytokines such as TNF-α, IL-6, VEGFR2, and TGF-ß, leading to increased re-epithelialization and collagen formation. Moreover, microbiological analysis confirmed that LM-GelMA can modulate the abundance of beneficial wound microbiota at family and genus levels. This study provides a facile strategy and insights into the functional design of hydrogels from the perspective of wound microenvironment regulation.

Effects of Bifidobacterium breve 207-1 on regulating lifestyle behaviors and mental wellness in healthy adults based on the microbiome-gut-brain axis: a randomized, double-blind, placebo-controlled trial.

PURPOSE: Our study aimed to explore the efficacy of Bifidobacterium breve 207-1 on specific neurotransmitters and hormones and the ability to regulate lifestyle behaviors in healthy adults. METHODS: In total, 120 healthy adults with high mental stress, overweight, insomnia, and constipation were randomly assigned to receive low-dose B. breve 207-1 (LD, n = 40), high-dose B. breve 207-1 (HD, n = 40), or placebo (n = 40) for 28 days. Fecal and blood samples were collected and questionnaires were answered before and after the trial. Neurotransmitters and serum hormones were detected using enzyme-linked immunosorbent assay. The gut microbiota composition was assessed using 16 S rRNA sequencing. Short-chain fatty acids (SCFAs) concentrations were determined via gas chromatography-mass spectrometry (GC-MS). RESULTS: The primary outcome of our study was changes in mental wellness, including neurotransmitters, the hypothalamic-pituitary-adrena (HPA) axis hormones, and the psychological scales. The results showed that γ-aminobutyric acid (GABA) increased significantly and the HPA axis hormones were suppressed overall in the probiotic groups while 5-hydroxytryptamine (5-HT) did not change significantly. However, there was no significant change in mood scale scores. The secondary outcome focused on the ability of 207-1 to regulate the body and lifestyle of healthy adults (e.g., sleep, diet, exercise, etc.). The PSQI scores in the probiotics groups significantly decreased, indicating improved sleep quality. Meanwhile, the probiotic groups had a slight increase in exercise consumption while dietary intake stabilized. By physical examination, the participants showed weight loss although no statistically significant difference was observed between the groups. Then, validated by gut microbiota, changes in the gut microbiota were observed under the effective intervention of 207-1 while short-chain fatty acids (SCFAs) increased in the LD group, particularly acetic and propionic acids. There was a slight decrease in alpha-diversity in the HD group. CONCLUSION: Bifidobacterium breve 207-1 entered the organism and affected neurotransmitter and the HPA axis hormone levels via the microbiome-gut-brain axis. Meanwhile, 207-1 supplementation improved daily lifestyle behaviors in healthy adults, which may in turn lead to changes in their bodies (e.g. weight and lipid metabolism). However, this study did not find significant mood-modulating efficacy. The mechanism of the overall study is unclear, but we hypothesize that SCFAs may be the key pathway, and more experiments are needed for validation in the future. TRIAL REGISTRATION: This trial was retrospectively registered in the Chinese Clinical Trial Registry under the accession number ChiCTR2300069453 on March 16, 2023.

[Relationship between gut microbiome and neurodevelopment in early life].

OBJECTIVE: To compare the differences in gut microbiome composition between children with good neurodevelopment and those with delayed neurodevelopment, and to analyze the relationship between gut microbiome and the neurodevelopment status of infants in early life. METHODS: The mothers were included at the Second West China Hospital from November 2020 to April 2021. Their infant stools were collected on day 0 and day 90 after birth, and the follow-up questionnaires at the corresponding time points were completed. Additionally, the Ages and Stages Questionnaires-Third Edition(ASQ-3) were completed by mothers at 12 months of age. The structure and diversity of gut microbiota were examined by 16S rRNA sequencing, and the relationship between gut microbiome and ASQ-3 questionnaire scores in early life was analyzed. RESULTS: According to the ASQ-3 scores, mothers and infants into neurodevelopment good group(G group, n=18) and neurodevelopmental delay group(D group, n=10). Compared with the D group, the relative abundance of the Firmicutes was significantly higher in the G group at day 0(P<0.05), while the level of the Proteobacteria was lower(P<0.05). At day 90 after birth, the relative abundance of the Actinobacteria, Bifidobacteriaceae and Enterococcaceae was significantly higher in the G group(P<0.05). In addition, alpha diversity was not statistically different between the two groups. Spearman's correlation analysis showed that Clostridiaceae of the postnatal day 0 infants was positively correlated with the communication domain score, but negatively associated with gross motor domain score in children at 12 months of age, whereas the relative abundance of Proteobacteria and Enterobacteriaceae of children at postnatal day 90 was negatively associated with communication development, while the relative abundance of Erysipelatoclostridiaceae showed a negative correlation with gross motor domain scores. CONCLUSION: The structure of the gut microbiome in early life between neurodevelopment good and delayed infants, and were associated with the development of communication and gross motor domain in infants at 12 months of age, suggesting that gut microbiome in early life may be related to the level of neurodevelopment in infants.

Breastfeeding might partially contribute to gut microbiota construction and stabilization of propionate metabolism in cesarean-section infants.

PURPOSE: This study was aimed to determine how delivery mode and feeding pattern influence the infant's gut microbiota construction and the variation of fecal microbial metabolites from a birth cohort. METHODS: Fecal samples collected from 61 full-term born Chinese infants at four time points: day 0, day 7, month 1, and month 3. Based on delivery mode (vaginal delivery [V] or cesarean section [C]) and feeding pattern (breastfeeding [B] or mixed feeding [M]), infants were divided into four groups, namely VB, CB, VM, and CM groups. The gut microbiota composition and bacterial diversity were assessed using 16S rRNA sequencing. Short-chain fatty acid (SCFA) concentrations were determined via gas chromatography-mass spectrometry (GC-MS). RESULTS: The CM group had a significantly higher relative abundance of Firmicutes (day 0 and month 1), Enterococcaceae (month 3), and Enterococcus (month 3) than the VB group and a significantly higher abundance of Firmicutes (month 1) and Blautia (month 3) than the CB group. The VB and CB groups exhibited a stable SCFA variation and a significantly lower level of propionate compared with the VM and CM groups. All groups showed an intense transition of enterotypes within 1 month and became stable at 3 months. The correlation between SCFA and enterotypes showed a significant positive correlation between Bifidobacteriaceae and acetate in the CB group (day 7 and month 3) and a significant positive correlation between Clostridiaceae and butyrate in the CB and VB groups (day 7 and month 3), respectively. CONCLUSION: These results indicated that C-section was associated with higher abundance of the phylum Firmicutes and family Enterococcaceae, and intense fluctuation of SCFA, at least propionate. And breastfeeding might partially contribute to gut microbiota construction and stabilization propionate metabolism in cesarean-section infants.

Bifidobacterium infantis and 2'-fucosyllactose supplementation in early life may have potential long-term benefits on gut microbiota, intestinal development, and immune function in mice.

The health benefits of nutritional interventions targeting the gut microbiota in early life are transient, such as probiotics, prebiotics, and synbiotics. This study sought to determine whether supplementation with Bifidobacterium infantis 79 (B79), 2'-fucosyllactose (2'-FL), or both (B79+2'FL) would lead to persistent health benefits in neonatal BALB/c mice. We found that at postnatal day (PND) 21, Ki67 and MUC2 expression increased, while total serum IgE content decreased in the B79, 2'-FL, and B79+2'-FL groups. The gut microbiota structure and composition altered as well. The levels of propionic acid, sIgA, and IL-10 increased in the 2'-FL group. Moreover, butyric acid content increased, while IL-6, IL-12p40, and tumor necrosis factor-α decreased in the B79+2'-FL group. At PND 56, Ki67 and MUC2 expression increased, whereas the gut microbiota remained altered in all 3 groups. The serum total IgG level increased only in the B79+2'-FL group. In conclusion, our study suggests that early-life supplementation with B79, 2'-FL, or their combination persistently alters the gut microbiome and promotes intestinal development; the immunomodulatory capacity of B79 and 2'-FL occurs during weaning, and their combination may persist into adulthood.

[Influence of different fecal microbiota transplantation cycles on the recovery of intestinal microbiota in the antibiotic cocktail-pretreated mice].

OBJECTIVE: To explore the effects of different transplantation frequencies and time of fecal microbiota transplantation on mice. METHODS: Twenty-four C57BL/6J mice were randomly divided into control group, fecal microbiota transplantation group 1(FMT1), fecal microbiota transplantation group 2(FMT2), and fecal microbiota transplantation group 3(FMT3). The control group was used as the donor of fecal microbiota transplantation, and the FMT1, FMT2, and FMT3 groups were intervened with mixed antibiotics(200 µL/d) for 2 weeks, and received fecal bacterial suspension(200 µL/d). The transplantation time of the FMT1 group frequency was 1 time/d for 1 weeks, the FMT2 group was 1 time/d for 2 weeks, and the FMT3 group was 3 times/week for 2 weeks. At the end of the experiment, the feces of the mice were collected to analyze the gut microbiota. RESULTS: Compared with the control group, there were more independent Amplicon Sequence Variants in the intestinal microbiota of mice in FMT1 group, FMT2 group and FMT3 group, and the ACE index and Chao1 index were significantly reduced(P<0.05). Beta diversity showed differences between fecal microbiota transplantation and control groups, with FMT2 and control groups being the closest. At the phylum level, there were two species in FMT1 group and one species in FMT3 group showed statistically significant differences compared with control group(P<0.05). However, there was no significant difference between the FMT2 group and the control group. At the genus level, there were 6 species in the FMT1 with statistically significant differences from the control group(P<0.05), and 2 species in the FMT2, 5 species in the FMT3 respectively. Among which FMT2 group has the least number of species that differed from the control group, suggesting that the compitsition of its intestinal microbiota is closet to that of the control group. CONCLUSION: Fecal bacteria transplantation helps to restore the intestinal microbiota structure of mice cleaned by antibiotics, and different transplantation frequencies and transplantation times have different recovery effects on the intestinal microbiota of mice pretreated with antibiotics, and the fecal bacteria transplantation effect is better with 1 time/d lasting 2 weeks.

[Heat-inactivated Streptococcus thermophilus MN002 alleviate lipid metabolism of high fat diet-fed induced obese mice through modulating gut microbiota structure and bile acids].

OBJECTIVE: To explore the effects of heat-inactivated Streptococcus thermophilus MN-ZLW-002(MN002) on glucose metabolism, lipid metabolism, gut microbiota and bile acids in high-fat diet fed obese mice. METHODS: Sixty 3-week-old male C57BL/6 mice were randomly divided into control group, high-fat group and intervention group(n=20). After 1 week of adaptive feeding, the control group was fed with normal chow and continued intragastric administration of normal saline for 12 weeks, the high-fat group was fed with high-fat diet and continued intragastric administration of normal saline for 12 weeks, and the intervention group was fed with high-fat diet and continued intragastric of MN002 for 12 weeks. During the experiment, the body weight, food intake, fasting blood glucose content of mice were measured and feces were collected. At the end of the experiment, the oral glucose tolerance of mice was measured and blood, periintestinal fat, peritestosterone fat and perirenal fat samples were collected. The histopathological changes of liver were observed by hematoxylin-eosin staining. Triglyceride, low density lipoprotein, high density lipoprotein and total cholesterol were detected by automatic biochemical analyzer, bile acids content in feces was detected by liquid chromatography-mass spectrometry, gut microbiota structure of mice was analyzed by 16S rDNA sequencing. RESULTS: Compared with high fat group, serum triglyceride, total cholesterol and perirenal fat in intervention group were significantly decreased(P<0.05), the content of fossil cholic acid sulfate in feces was significantly increased, while the content of ursodeoxycholic acid, porcine deoxycholic acid and deoxycholic acid were significantly decreased(P<0.01). Heat inactivation of MN002 could significantly increase the relative abundance of Ruminiclostridium and Alistipes and reduce the relative abundance of Lactobacillus(P<0.01). CONCLUSION: Heat-inactivated Streptococcus thermophilus MN002 can regulate the gut microbiota structure and bile acid composition and content of high-fat diet fed mice, thereby alleviating the lipid metabolic disorders caused by high-fat diet.

Sex discrepancy in establishing mouse visceral obesity model induced by high-fat diet. / é«˜è„‚é¥®é£Ÿè¯±å¯¼çš„å† è„è‚¥èƒ–å°é¼ æ¨¡åž‹å­˜åœ¨æ€§åˆ«å·®å¼‚.

OBJECTIVES: To establish a mouse visceral obesity model, and to investigate the effect of animal sex on this model. METHODS: Thirty-two 4-week-old BALB/c mice were randomly divided into female control group, female high-fat group, male control group and male high-fat group with 8 mice in each group.The control groups were given ordinary diet, and the high-fat groups were given high-fat diet. After 12 weeks of feeding, body weight, visceral fat, fasting blood glucose, glucose tolerance, blood lipid and metabolism-related hormone levels were measured, and the composition of gut microbiota of mice was analyzed by 16S rRNA sequencing. RESULTS: The high fat diet resulted in a significant increase of body weight and visceral fat content in male mice; the pathological results showed significantly increased fat area, accumulation of liver fat droplets, increased total cholesterol, fasting blood glucose, oral glucose tolerance and serum insulin levels (all P<0.05), as well as significant insulin resistance (P<0.01). However, the above changes were not significant in female mice. Compared with the control groups, there was an increase in the relative abundance of obesity-related gut microbiota in the model groups (such as Blautia), and the microbiota structure changed significantly, while the changes were less obvious in female mice. CONCLUSIONS: A visceral obesity mouse model has been stably established by feeding high-fat diet in BALB/c male mice, showing visceral fat accumulation, metabolic dysfunction and gut microbiota changes; while female mice are not sensitive in this obesity model.

Antibiotic cocktail-induced gut microbiota depletion in different stages could cause host cognitive impairment and emotional disorders in adulthood in different manners.

Gut microbiota depletion may result in cognitive impairment and emotional disorder. This study aimed to determine the possible association between host gut microbiota, cognitive function, and emotion in various life stages and its related underlying mechanisms. Seventy-five neonatal mice were randomly divided into five groups (n = 15 per group). Mice in the vehicle group were administered distilled water from birth to death, and those in the last four groups were administered antibiotic cocktail from birth to death, from birth to postnatal day (PND) 21 (infancy), from PND 21 to 56 (adolescence), and from PND 57 to 84 (adulthood), respectively. Antibiotic exposure consistently altered the gut microbiota composition and decreased the diversity of gut microbiota. Proteobacteria were the predominant bacteria instead of Firmicutes and Bacteroidetes after antibiotic exposure in different life stages. Long-term and infant gut microbiota depletion resulted in anxiety- and depression-like behaviors, memory impairments, and increased expression of γ-aminobutyric acid type A receptor α1 of adult mice. Long-term antibiotic exposure also significantly decreased serum interleukin (IL)-1ß, IL-10, and corticosterone of adult mice. Gut microbiota depletion in adolescence resulted in anxiety-like behaviors, short-term memory decline, decreased serum interferon-γ (IFN-γ), mRNA expression of 5-hydroxytryptamine receptor 1A, and neuropeptide Y receptor Y2 in the prefrontal cortex of adult mice. Antibiotic exposure in adulthood damaged short-term memory and decreased serum IL-10, IFN-γ, and increased γ-aminobutyric acid type B receptor 1 mRNA expression of adult mice. These results suggest that antibiotic-induced gut microbiota depletion in the long term and infancy resulted in the most severe cognitive and emotional disorders followed by depletion in adolescence and adulthood. These results also suggest that gut microbes could influence host cognitive function and emotion in a life stage-dependent manner by affecting the function of the immune system, hypothalamic-pituitary-adrenal axis, and the expression of neurochemicals in the brain.

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.

[Protective effect and mechanism of Bifidobacterium bifidum TMC3115 on long-term colitis in mice which exposed to antibiotic in early life].

OBJECTIVE: To explore the protective effect and mechanism of Bifidobacterium bifidum TMC3115 of improving the gut microbiota disorder caused by antibiotic exposurein early life, and the possible protection of inflammatory bowel disease in adulthood in mice. METHODS: 80 newborn mice were randomly divided into 3 groups, a blank control group(n=40), a ceftriaxone exposure group(n=20), a Bifidobacterium bifidum TMC3115 intervention group(n=20). After birth, they were respectively treated with saline, ceftriaxone(100 mg/kg), and ceftriaxone(100 mg/kg) + TMC3115(1×10~9CFU/d) for 3 weeks. After 3 weeks, half of each group was randomly sacrificed, and the rest were normally fed to 6 weeks. At 6 weeks, the blank control group was randomly divided into a negative control group(n=10) and a colitis model group(n=10). The negative control group drunk pure water freely, and the other three groups were added 3% DSS to the drinking water for 4 days to induce colitis. At 6 weeks and 4 days, the remaining mice were sacrificed. The weight change, spleen coefficient, gut microbiota analysis based on second-generation sequencing and serum tumor necrosis factor-α(TNF-α), interleukin-6(IL-6), and interleukin-10(IL-10)levels of the mice at 3 weeks and after DSS intervention were recorded. In addition, the colon length and inflammation pathology score of the mice after DSS intervention were also measured. RESULTS: At 3 weeks, compared with the control, antibiotic exposure in the early life inhibited the weight gain and reduced the diversity and uniformity of the gut microbiota of the mice(P<0.05). The intervention of TMC3115 under antibiotic exposure during this period increased the relative abundance of Bifidobacterium in the intestines(P<0.05), and the effect still existed after DSS stimulation in adulthood, laying the foundation for TMC3115 to exert long-term benefits. After DSS stimulation in adulthood, mice showed significant weight gain inhibition, colon length shorteningand inflammation pathology scoreincrease compared with the negative control(P<0.05), showed the inflammatory bowel disease(IBD)model was successfully constructed. The relative abundance of beneficial bacteria such as Lactobacillus in the Bifidobacterium bifidum TMC3115 intervention group increased compared with the ceftriaxone exposure group(P<0.05), while the relative abundance of harmful bacteria such as Staphylococcus, Clostridium, and Desulfovibrio decreased(P<0.05). Furthermore, the mice exposed to antibiotic in early life produced a stronger immune response, but the mice which received TMC3115 intervention at the same time had a significant decrease in serum TNF-α and IL-6 levels and increase in IL-10 level compared with the mice which only interfered with antibiotics(P<0.05). CONCLUSION: Antibiotic exposure in early life is a negative factor for long-term inflammatory bowel disease, and TMC3115 has preventive significance for long-term inflammatory bowel disease under the background of antibiotic exposure. The mechanism of TMC3115 may be to adjust the gut microbiota and balance the immune system.

[Bifidobacterium bifidum TMC3115 Promotes Early Life Intestinal Microbiota Building to Alleviate Symptoms of Inflammatory Bowel Disease].

Objective: To investigate the effects of using Bifidobacterium bifidum TMC3115 in early life on intestinal microbiota and immune functions and the long-term impact on inflammatory bowel disease. Methods: Fourteen pregnant BALB/c mice were purchased and 84 newborn BALB/c mice were subsequently obtained. Then, the newborn mice were randomly assigned to a normal saline (NS) group and a TMC3115 group, given via oral gavage normal saline and TMC3115, respectively, at a daily volume of 0.2 mL for each mouse. About 42 mice were assigned to each group. The gavage was stopped after 3 weeks. At this point, half of the mice in each group were sacrificed, and then the remaining mice in each group were randomly divided into NS-water group, NS-DSS group, TMC3115-water group, and TMC3115-DSS group, with about 10 mice in each group. The mice were given regular feed until the end of week 6 when they were given 3% dextran sulphate sodium (DSS) ad libitum for 4 days to establish the enteritis model, while the non-modeling groups were given pure water ad libitum. The experiment ended after 6 weeks and 4 days. The weekly body mass changes of the mice were documented. The intestinal tissue at the end of the experiment and the fecal samples, spleen and serum of the mice at 3 weeks and at the end of the experiment were collected to determine the pathology scores of colonic inflammation, the composition of fecal gut microbiota, spleen organ index and the mass concentration of serum cytokines. Results: 1) At the end of the experiment, the inflammatory pathology score was significantly lower in the TMC3115-DSS group compared with that of the Saline-DSS group ( P<0.05), with less disruption of colonic crypt structures and other structures, less inflammatory infiltration, and more intact epithelial structures. 2) At 3 weeks, in comparison with those of the NS group, the relative abundance of Bifidobacteriumwas significantly higher in the feces of the TMC3115 ( P<0.05), the relative abundance of both Enterococcusand Staphylococcuswas lower ( P<0.05), the splenic organ index was significantly higher ( P<0.05), and interleukin (IL)-10 was significantly decreased ( P<0.05), while there was no significant change in IL-6 or TNF-α ( P>0.05). At the end of the experiment, in comparison with those of the NS-DSS group that undergone DSS induction, the TMC3115-DSS group had reduced relative abundance of Staphylococcus, Staphylococcus tumefaciens and Escherichia/ Shigellain the feces ( P<0.05), while the splenic organ index was significantly higher ( P<0.05), and there were no significant changes in IL-6 or TNF-α ( P>0.05). Conclusion: The use of TMC3115 in early life promotes the construction of gut microbiota in neonatal mice, thereby producing a long-term effect that alleviates colitis in mice, but the mechanisms involved are still not fully understood.

[High-fat diet induces metabolic syndrome in mice and its influence on intestinal development, liver function and intestinal microbiota].

OBJECTIVE: To evaluate the possibility of high-fat diet to induce metabolic syndrome and to alter intestinal development, liver function and intestinal microbiotaof C57 BL/6 J mice. METHODS: Total 40 of male C57 BL/6 J aged 3 weeks old were randomly divided into two groups: control group and high-fat diet group. After one week of adaptive feeding, the tested mice in high-fat diet group were fed with high-fat diet for 20 weeks, while those in control group were fed with ordinary diet. During the intervention, the body weight of the tested mice was measured weekly and fasting blood glucose(FBG) was measured monthly. Before the end of the experiment, the oral glucose tolerance test(OGTT) of the tested mice was conducted and the fecal 16 S rRNA sequencing was used to profile fecal microbiota of the test mice. Real-time qPCR was used to analyze the concentration of fecal bifidobacteria. Viscera coefficient of liver, spleen and pancreas, visceral fat-body ratio and intestinal length were measured. The indexes of liver function and the levels of serum lipids, leptin and adiponectin were also measured. Liver inflammation and fat infiltration were observed by anatomical pathological analysis. RESULTS: After intervention of high fat diet, the body weight, FBG, oral glucose tolerance, the fat-body ratio, the levels of serum lipids, leptin and adiponectin of mice were significantly increased(P<0. 05). The inflammatory state of liver and the degree of fat infiltration increased. The length of intestine decreased(P<0. 05). The concentration of Bifidobacterium decreased(P<0. 05), however, the concentration of B. bifidum and B. angulatum increased(P<0. 05). The ACE, Chao1, Shannon and Simpson indexes of the high-fat diet were significantly lower than that of the control group(P<0. 05). Firmicutes, Proteobacteria and Deferribacteres were found significantly more in high-fat diet group(P<0. 05), while Bacteroidetes and Verrucomicrobia were apparently more in control group(P<0. 05). CONCLUSION: High-fat diet could induce the metabolic syndrome in tested C57 BL/6 J, and lead to the damage of intestinal development, abnormality of liver tissue and its function, decrease diversity of intestinal microbiota, and the transformation of intestinal microbiota community to obesity type.

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.

[Effects of oral administration of ceftriaxone in early life on glucolipid metabolism of high fat diet-induced mice].

OBJECTIVE: This study aimed to explore whether exposure to ceftriaxone during early life could influences glucose and lipid metabolism of high fat diet-induced mice. METHODS: Total 48 of female BALB/c aged 2 week old were randomly divided into control group(treated with saline), antibiotic group(treated with100 mg/kg ceftriaxone), high-fat diet group(treated with saline) and combined action group(treated with 100 mg/kg ceftriaxone)(n=12), respectively to stop gavage 2 weeks later. Then high-fat diet group and combined action group were fed with high-fat diet for 12 weeks. Fasting blood glucose(FBG) and oral glucose tolerance test were conducted in the last week. Serum total cholesterol(TC), triglyceride(TG), high-density lipoprotein cholesterol(HDL-C), low-density lipoprotein cholesterol(LDL-C), fasting insulin, leptin and TG, TC in liver were also measured. Furthermore, homeostasis model assessment of insulin resistance(HOMA-IR) was calculated from FBG and insulin. RESULTS: Compared with normal chow diet, high-fat diet impaired oral glucose tolerance and increased the levels of abdominal adipose tissue, FBG, HOMA-IR, lips in serum and liver and leptin(P<0. 05). The oral administration of ceftriaxone in early life impaired oral glucose tolerance and increased the levels of abdominal adipose tissue, FBG and TG in liver(P<0. 05). In addition, early ceftriaxone intervention could enhance the impaired glucose tolerance, the increasing FBG, insulin resistance and liver lipids associated with high-fat diet(P<0. 05). CONCLUSION: Early ceftriaxone intervention not only significantly increases the level of abdominal adipose tissue, FBG, insulin resistance and liver lipids, but also enhances glycolipid metabolic disorders induced by high-fat diet. These result suggest that the exposure to antibiotics in the early life might increase the sensitivity of host animal to high fat diet induced abnormal glycolipid metabolism late.

[Intestine lactobacilli of 1-4 months infant and characterize their biochemical properties in Chengdu City in 2015-2016].

OBJECTIVE: To collect intestinal lactobacilli in healthy infants and to characterize them biochemically for further studies. METHODS: Lactobacilli were isolated from the fecal samples collected from total 41 of 1-4 month old healthy infants with culture method by selective medium. After morphological observation and oxygen test, the isolates were tested for their abilities to use 50 carbohydrate and identified with API 50 CHL system and 16 S RNA sequencing. The isolates were also detected for their 19 enzyme activities with API ZYM system. RESULTS: A total of 71 Lactobacillus strains were successfully isolated and well identified, including L. paracasei( 42. 3%), L. gasseri( 18. 3%), L. salivarius( 14. 1%), L. brevis( 5. 6%), L. rhamnosus( 4. 2%), L. fermentum( 1. 4%), L. plantarum( 1. 4%) and other species( 12. 7%). The seven species of Lactobacillus had strong ability of utilizing carbohydrate. Except for 14 carbohydrates that could not be fermentable, 4 kinds of carbohydrates could be metabolized by all lactobacilli from the seven species, and the other 31 kinds of carbohydrates were metabolized differently among species. Most lactobacilli were active on Leucine arylamidase, Galactosidase and Glucosidase, while other enzyme activities were species-specific and strains-specific. CONCLUSION: L. paracasei, L. gasseri and L. salivarius could be considered as dominant species of 1-4 months healthy infants. However, the carbohydrate utilization and enzyme activities of the fecal lactobacilli might be species and strain dependent.

[Effect of ceftriaxone on the intestinal epithelium and microbiota in neonatal mice].

OBJECTIVE: To investigate the effect of ceftriaxone on the intestinal epithelium and microbiota in mice in the early-life stage, as well as the recovery of the intestinal epithelium and reconstruction of intestinal microbiota in adult mice. METHODS: A total of 36 BALB/C neonatal mice were randomly divided into control group and experimental group, with 18 mice in each group. The mice in the experimental group were given ceftriaxone 100 mg/kg every day by gavage within 21 days after birth. Those in the control group were given an equal volume of normal saline by gavage. Immunohistochemistry was used to measure the expression of Ki67, Muc2, and ZO-1 in the intestinal epithelium. qPCR and next-generation sequencing were used to analyze the overall concentration and composition of fecal bacteria. RESULTS: After 21 days of ceftriaxone intervention, the experimental group had a significant reduction in body weight, a significant reduction in the expression of Ki67 and ZO-1 and a significant increase in the expression of Muc2 in intestinal epithelial cells, a significant reduction in the overall concentration of fecal bacteria, and a significant increase in the diversity of fecal bacteria compared with the control group (P<0.05). Firmicutes was the most common type of fecal bacteria in the experimental group, and there were large amounts of Staphylococcus and Enterococcus. The experimental group had a certain degree of recovery of the intestinal epithelium, but there were still significant differences in body weight and the structure of intestinal microbiota between the two groups at 56 days after birth (P<0.05). CONCLUSIONS: Early ceftriaxone intervention significantly affects the development of the intestinal epithelium and the construction of intestinal microbiota in the early-life stage. The injury of the intestinal microbiota in the early-life stage may continue to the adult stage and affect growth and development and physiological metabolism.

Live and Heat-Inactivated Streptococcus thermophilus MN-ZLW-002 Mediate the Gut-Brain Axis, Alleviating Cognitive Dysfunction in APP/PS1 Mice.

Research on regulating brain functions with probiotics and postbiotics through the gut-brain axis is attracting attention, offering the possibility of adjuvant therapy for Alzheimer's disease (AD). Three-month-old male APP/PS1 mice were gavaged with live and heat-inactivated S. thermophilus MN-002 for three months. This study demonstrated that live and heat-inactivated S. thermophilus MN-002 improved cognitive dysfunctions in APP/PS1 mice, especially in spatial memory. However, the main effects of live S. thermophilus MN-002 directly altered the intestinal microbiota composition and increased serum IL-1ß and IL-6. Heat-inactivated S. thermophilus MN-002 increased colonic propionic acid levels and enhanced the hippocampus's antioxidant capacity. Furthermore, the changes were more obvious in the high-dose group, such as astrogliosis in the hippocampus. These results indicate that different forms and doses of the same strain, S. thermophilus MN-002, can partly improve cognitive functions in AD model mice via the gut-brain axis.

Gut Microbiota Perturbation in Early Life Could Influence Pediatric Blood Pressure Regulation in a Sex-Dependent Manner in Juvenile Rats.

The present study aimed to investigate whether gut dysbiosis induced by ceftriaxone in early life could influence pediatric blood pressure regulation in childhood with or without exposure to a high-fat diet (HFD). Sixty-three newborn pups of Sprague-Dawley rats were administered ceftriaxone sodium or saline solution until weaning at 3 weeks, and the rats were fed a HFD or regular diet from 3 to 6 weeks. Tail-cuff blood pressure, the expression levels of genes of the renin-angiotensin system (RAS), the concentrations of IL-1ß, IL-6, and TNF-α in the colon and prefrontal cortex, and the composition of fecal microbiota were analyzed. Ceftriaxone treatment significantly increased the diastolic blood pressure of male rats at 3 weeks. At 6 weeks, systolic blood pressure (SBP) was significantly increased only in ceftriaxone treated male rats fed with HFD. The RAS showed increased activation in the kidney, heart, hypothalamus, and thoracic and abdominal aorta of male rats, but only in the kidney, heart, and hypothalamus of female rats. HFD-fed female rats showed a decreased level of IL-6 in the colon. α diversity of gut microbiota decreased and the Firmicutes to Bacteroidetes ratio increased in both male and female rats at 3 weeks; however, these parameters recovered to various degrees in female rats at 6 weeks. These results revealed that early-life gut dysbiosis induced by antibiotics combined with a HFD in childhood could be involved in pediatric blood pressure regulation and an increase in SBP in juvenile rats, and these effects occurred in a sex-dependent manner.