OBJECTIVES: To investigate the effects of early life intervention with Bifidobacterium bifidum BD-1 (B. bifidum BD-1) on hyperactivity in a female mouse model of attention deficit hyperactivity disorder (ADHD) and explore the underlying mechanisms. METHODS: Eight newborn female Wistar-Kyoto (WKY) rats and 6 spontaneous hypertensive rats (SHRs) were gavaged with saline and another 6 SHRs were gavaged with B. bifidum BD-1 (10⁹ CFU) daily for 3 weeks. Open field test of the rats was conducted at 7 weeks, and fecal samples were collected at weaning (3 weeks) and at 7 weeks for 16S rRNA sequencing. Immunofluorescent staining was used to detect dopamine transporter (DAT) and tyrosine hydroxylase (Th) levels in the striatum and activated microglia in the prefrontal cortex. Treg cells in the mesenteric lymph nodes, spleen and blood were analyzed using flow cytometry. RESULTS: The SHRs traveled a significantly greater distance in open fields test than WKY rats, and this behavior was significantly attenuated by B. bifidum BD-1 intervention. The expression of DAT and Th in the striatum was significantly lower in the SHRs than in WKY rats, while B. bifidum BD-1 treatment obviously increased Th levels in the SHRs. B. bifidum BD-1 intervention significantly deceased the number of activated microglia and increased Treg cell counts in the spleen of SHRs. The treatment also enhanced α diversity in gut microbiota of the SHRs and resulted in a decreased Firmicutes/Bacteroidota ratio, more active Muribaculaceae growth, and suppression of Clostridia_UCG-014 proliferation. CONCLUSIONS Early life intervention with B. bifidum BD-1 alleviates hyperactivity in female SHRs by modulating the gut microbiota and peripheral immune response, suppressing neuroinflammation and improving dopaminergic system function. These findings provide evidence for early prevention strategies and support the development and application of psychobiotics for ADHD.
Animals ; Female ; Rats ; Rats, Inbred WKY ; Rats, Inbred SHR ; Attention Deficit Disorder with Hyperactivity/therapy* ; Bifidobacterium bifidum ; Probiotics/therapeutic use* ; Dopamine Plasma Membrane Transport Proteins/metabolism* ; Tyrosine 3-Monooxygenase/metabolism* ; Gastrointestinal Microbiome ; Disease Models, Animal

Objective To make a preliminary investigation of the effect of the immune pathway mediated by live Lacticaseibacillus paracasei N11 15 on the development of primary hippocampal neurons cultured in vitro.Methods Live Lacticaseibacillus paracasei N1115 suspension of an appropriate concentration was used as the experimental group.Peptidoglycan(PGN)and lipopolysaccharide(LPS)were used as positive controls,and RPMI1640 medium served as the blank control.These were co-cultured with RAW264.7 cells to obtain the co-culture mediums and the total cellular RNA,and to measure the expression and secretion of cytokines.After centrifugation,the supernatants were co-cultured with primary hippocampal neurons at appropriate ratios.The co-culture mediums were collected,and the total cellular RNA was extracted to measure the expression of genes related to synaptic development in neurons.Following immunofluorescence staining of the primary hippocampal neurons,the presynaptic and presynaptic membrane-associated proteins,including synaptophysin(SYP)and the postsynaptic density protein 95(PSD95),and neuronal cell maturation markers,including microtubule-associated protein 2(MAP-2),and doublecortin(DCX)were quantitatively analyzed.Additionally,the morphological development of the neurons were measured.Results Compared with the blank control,the mRNA expression levels of interleukin(IL)-6 and tumor necrosis factor-α(TNF-α)increased by 7471％and 926％,respectively,after the RAW264.7 cells were treated with live Lacticaseibacillus paracasei N1115,while their secretion levels increased by 184.16 pg/mL and 12320.76 pg/mL,respectively,all showing statistically significant differences(P＜0.05).The activation ability of N1115 live bacteria was stronger than that of PGN but weaker than that of LPS,showing statistically significant differences(P＜0.05).Compared with the blank control,following the intervention with the supernatant from the co-culture of N1115 live bacteria and RAW264.7 cells,the viability of primary hippocampal neurons in the 10％supernatant intervention group increased by 19.25％,showing statistically significant differences(P＜0.05),and the mRNA expression of SYP and PSD95 increased by 137％and 159％,respectively,showing statistically significant differences(P＜0.05).The total neurite length(489.88 μm)of the neurons of the group intervened with the supernatant of N11 15 live bacteria was increased compared to that of the blank control group(381.51 μm),and the cell body area(2092.22 μm2),maximum neurite length(184.78 μm),total neurite length,average neurite length(108.38 μm),and branching points(4.84 s)were higher than those in the two positive control groups,showing statistically significant differences(P＜0.05).Conclusion Lacticaseibacillus paracasei N1115 can significantly activate the immune regulatory function of macrophages,thereby promoting the morphological development and synaptic function of nerve cells.

In this research, we compared the visual neuron responses for LGN, A18 and PMLS of old and young cats with extracellular single-neuron recording techniques. We used firing rate vector to characterize information, and response irregularity of cells to evaluate the degeneration of visual characters. Response irregularity is characterized by means of the two coefficients of variation of firing rate vectors: Cv and Cv2. We found that there was no significant change of the response irregularity in LGN areas during the aging process from young to old cats. But in the other two areas, neurons of old cats exhibited significantly larger response irregularity than those of young cats. The result indicated that the information processing function of advanced visual cortex was impaired by aging. This result also provids a reference for the research of the other neuronal system changes during aging process.
Action Potentials ; physiology ; Aging ; physiology ; Animals ; Cats ; Neural Conduction ; Neurons ; physiology ; Visual Cortex ; physiology