Complex probiotics alleviate ampicillin-induced antibiotic-associated diarrhea in mice.

Aim: Antibiotic-associated diarrhea (AAD) is a common side effect during antibiotic treatment, which can cause dysbacteriosis of the gut microbiota. Previous studies have shown beneficial effects in AAD treatment with Bifidobacterium lactis XLTG11, Lactobacillus casei Zhang, Lactobacillus plantarum CCFM8661, and Lactobacillus rhamnosus Probio-M9. However, no studies have been conducted on the immunomodulatory effects and protective intestinal barrier function of four complex probiotics. The aim of our study is to investigate the alleviation effects of complex probiotics on ampicillin-induced AAD. Methods: Thirty-six BALB/c mice were randomly divided into six groups: normal control group (NC), model control group (MC), low-, medium-, and high-dose probiotics groups (LD, MD, and HD), and positive drug (Bifico, 1 × 107 cfu) control group (PDC; Bifico, also known as Bifidobacterium Triple Live Capsule, is composed of Bifidobacterium longum, Lactobacillus acidophilus, and Enterococcus faecalis). An AAD model was established by intragastric administration of ampicillin, by gavage of different doses of complex probiotics and Bifico. The weight gain, fecal water content, loose stool grade, intestinal permeability, total protein and albumin levels, intestinal barrier, cytokine levels, and gut microbiota were determined. Results: The results showed that complex probiotics significantly decreased the fecal water content, loose stool grade, intestinal permeability, and ileum tissue damage. Their application increased the weight gain, SIgA, TP, and ALB levels. Additionally, complex probiotics significantly decreased the levels of pro-inflammatory cytokines and increased those of anti-inflammatory cytokines. Meanwhile, the mRNA expression levels of ZO-1, occludin, claudin-1, and MUC2 were significantly upregulated in the probiotic-treated group. Furthermore, the complex probiotics increased the gut microbiota diversity and modulated the changes in the gut microbiota composition caused by ampicillin. At the phylum level, the abundance of Proteobacteria in the HD group was lower than that in the MC group, whereas that of Bacteroidetes was higher. At the genus level, the abundances of Klebsiella and Parabacteroides in the HD group were lower, whereas those of Bacteroides, Muribaculaceae, and Lactobacillus were higher than those in the MC group. Moreover, Spearman's correlation analysis also found that several specific gut microbiota were significantly correlated with AAD-related indicators. Conclusion: We found that complex probiotics improved the diarrhea-related indexes, regulated gut microbiota composition and diversity, increased the expression levels of intestinal protective barrier-related genes, preserved the intestinal barrier function, and relieved inflammation and intestinal injury, thereby effectively improving AAD-associated symptoms. Graphical Abstract.

Mood, hormone levels, metabolic and sleep across the menopausal transition in VCD-induced ICR mice.

AIMS: Menopausal transition is the transitional period before menopause in women, often accompanied by abnormal fluctuations in hormone levels that increase the risk of aging-related diseases. 4-vinylcyclohexene dioxide (VCD) is a chemical agent that induces gradual depletion of ovarian follicles, which can mimic the natural human process of transition from menopausal transition to post-menopause. Previous studies have shown that the onset of menopausal transition or menopause in VCD-injected mice is associated with a specific strain, even in inbred animals. Institute of Cancer Research (ICR) mice constitute general purpose outbred population, which has not been well-characterized in the VCD-induced model. Thus, the current study aimed to explore the characteristic features, including sleep, mood, and metabolism, of the model by examining the effect of timing of VCD injection in ICR mice to extend the applications of this model. MATERIALS AND METHODS: ICR mice were randomly divided into six groups: 20d VCD and 20d Control, 35d VCD and 35d Control, 52d VCD and 52d Control. VCD mice were intraperitoneally injected with VCD (160 mg/kg), while Control mice were injected intraperitoneally with sesame oil for 4 consecutive weeks, five times a week daily. A vaginal smear was used to observe the estrous cycle of the mice. On the 20th, 35th, and 52nd day after VCD or sesame oil injection, the ovarian morphology, the number of atretic cells, hormone levels, anxiety, depression-like behaviors, sleep phase, and energy metabolism were observed. KEY FINDINGS: The menopausal transition model was successfully replicated by injecting VCD into ICR mice. On the specific days after VCD treatment, the number of atretic follicles increased, the level of E2 decreased and FSH increased, the depressive- and anxiety-like behavior increased, the time of REM and NREM sleep time decreased, and energy metabolism was reduced. SIGNIFICANCE: These results suggested that the ICR mice model has human-like characteristics during the menopause transition. Moreover, the ICR model has a long menopausal transition duration.

Immunomodulatory effects of complex probiotics on the immuno-suppressed mice induced by cyclophosphamide.

Introduction: Previous studies have reported the beneficial effects of Bifidobacterium animalis subsp. lactis XLTG11, Lacticaseibacillus casei Zhang, and Lactiplantibacillus plantarum P8, respectively. However, studies on the immunomodulatory enhancing effects of three complex probiotics have not been conducted. The aim of our study is to investigate the immunomodulatory effects of complex probiotics effect on the immunosuppressed mice induced by cyclophosphamide (CTX). Methods: An immunocompromised mouse model was established by intraperitoneal injection of cyclophosphamide, which was gavage of different doses of complex probiotics and levamisole hydrochloride. The splenic and thymic indices, intestinal barrier, leukocyte and lymphocyte counts, percentage of splenic lymphocyte subpopulations, cytokine levels, and gut microbiota were determined. Results: Results showed that the complex probiotics significantly elevated the spleen and thymus indices, increased the villi and crypt depth and the goblet cells. The leukocyte and lymphocyte counts and the percentage of splenic lymphocyte subpopulations in the CTX-treated mice were significantly elevated by the complex probiotics. In addition, the cytokines (IL-6, IL-10, IL-1ß, and IFN-γ) were significantly increased after complex probiotic treatment. The complex probiotics restored the gut microbiota structure to the pattern of the control group by reducing the ratio of Firmicutes/Bacteroidetes and enhancing the relative abundances of specific microbiota that produced short-chain fatty acids. Discussion: This study provides theoretical support for the immunity-enhancing function of the complex probiotics as well as a pharmacological basis for its further development and utilization.

Effect of evaluation timing and duration of anxiety-like behaviors induced by conditioned fear in rats: Assessment using the triple test.

The fear conditioning-based models of anxiety disorders have been widely used for assessing anxiolytic action. The triple test is an evaluation method for anxiety-like behaviors that integrates the open field, elevated plus maze, and light/dark box, which can comprehensively reflect the anxiety-like behaviors state of animals. However, there are many factors that can affect the evaluation results of anxiety-like behaviors, especially the time of day (morning or afternoon), which are often ignored by most experimental studies. Accordingly, in the present study, we first measured the anxiety-like behavior in the fear conditioning-based model rats by using the triple test in the morning and afternoon, respectively (experiment 1). In experiment 2, the anxiety-like behaviors were evaluated on the 1st, 7th, 10th and 14th day after experiencing foot shock for 4 consecutive days, respectively. The fear-conditioned rats exhibited increased anxiety-like behaviors only in the afternoon and prolonged freezing times either in the morning and afternoon. Furthermore, model rats exhibit increased anxiety-like behaviors in open field, elevated plus maze, and light/dark box on the 1st day; in open field and light/dark box on the 7th day; in elevated plus maze on the 10th day; and in light/dark box on the 14th day after the final foot shock. The results suggested that the time of day had a significant effect on anxiety-like behaviors caused by conditioned fear, and increased in the afternoon vs morning. Moreover, the lasting increased in anxiety-like behavior for 14 days was appropriated to explore the effects of long-term administration of anxiolytics.

Development of hexagonal maze procedure for evaluating memory in rat.

Memory is known as a series of behavioral changes caused by an experience, while learning is a process for acquiring memory. In the present study, we suggested a new method (hexagonal maze) to evaluate the learning and memory of rats. For preliminary validation, the authors used the maze to carry out two classical experiments. At first, the performance of rats of various ages was observed in the maze. Additionally, after establishing the rapid eye movement (REM) sleep deprivation model using the modified multiple platform method (MMPM), the authors also utilized a new experimental device to analyze learning and memory responses to REM sleep deprivation in rats. Behavior of the rats in the maze was recorded by a video recorder and was then quantified. According to the behavioral characteristics, rats of various ages showed differences in memory. Middle-aged male rats exhibited a higher level compared to the young (P<0.05) and the old group (P<0.01). The results also indicated that the ability of learning and memory showed a significant decrease (P<0.05) after REM sleep deprivation. These findings were consistent with those of several similar studies using one of the adopted procedures (Morris water maze, radial arm maze and the Y-maze). Based on the above-mentioned preliminary experiments, the introduction of a hexagonal maze may provide an applicable method for analyzing learning and memory of rat.