Intracerebroventricular injection of propionic acid, an enteric bacterial metabolic end-product, impairs social behavior in the rat: Implications for an animal model of autism

Introduction: A neurodevelopmental disorder, autism typically identified with three primary behavioral consequences, such as social impairment, communication problems and limited or stereotypical behavior. Because of its co-morbidity and lack of therapeutic options, autism is a global economic burden. A short chain of fatty acid, propionic acid formed biologically by gut microbiome. Propionic acid levels that are too high can cause leaky intestines, which can lead to autism-like symptoms. Methods: To induce autism, male Albino Wistar rats were given propionic acid (250 mg/kg / po on the 21st, 22nd, and 23rd postnatal days). Rats were also received a ryanodine receptor antagonist (Ruthenium red: 3 mg/kg/po; postnatal 21st to 50th day) to see what influence it had on the propionic acid-induced autism. Anxiety, social behavior, and repeated behaviors were all assessed, as well as oxidative stress, inflammatory indicators, neuro signaling proteins, and blood brain barrier permeability. Results: Ruthenium red was found to counter the propionic acid induced increases in anxiety, repetitive behavior prefrontal cortex levels of IL-6, TNF-α, TBARS, Evans blue leakage and water content along with decreases in social behavior, IL-10, and GSH followed by hippocampus CREB and BDNF levels. Conclusion: Ryanodine receptor antagonist presented neuroprotective effect in propionic acid induced conditions like autism by modulatory effects on social and repetitive behavior, oxidative stress, neuroinflammation, and neuroprotein changes. Ryanodine receptors can be further explored in depth to manage autism as a condition.

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Lactobacillus plantarum PS128 prevents cognitive dysfunction in Alzheimer’s disease mice by modulating propionic acid levels, glycogen synthase kinase 3 beta activity, and gliosis

BMC Complementary Medicine and Therapies ◽

10.1186/s12906-021-03426-8 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Hei-Jen Huang ◽

Jie-Ling Chen ◽

Jian-Fu Liao ◽

Yu-Hsin Chen ◽

Min-Wei Chieu ◽

...

Keyword(s):

Lactobacillus Plantarum ◽

Propionic Acid ◽

Cognitive Dysfunction ◽

Glycogen Synthase ◽

Amyloid Β ◽

Glycogen Synthase Kinase ◽

Glycogen Synthase Kinase 3 ◽

Beta Activity ◽

Intracerebroventricular Injection ◽

Beneficial Effects

Abstract Background According to recent evidence, psychobiotics exert beneficial effects on central nervous system-related diseases, such as mental disorders. Lactobacillus plantarum PS128 (PS128), a novel psychobiotic strain, improves motor function, depression, and anxiety behaviors. However, the psychobiotic effects and mechanisms of PS128 in Alzheimer’s disease (AD) remain to be explored. Objectives The goal of the current study was to evaluate the beneficial effects of PS128 and to further elucidate its mechanism in AD mice. Methods PS128 (1010 colony-forming unit (CFU)/ml) was administered via oral gavage (o.g.) to 6-month-old male wild-type B6 and 3 × Tg-AD mice (harboring the PS1M146V, APPswe and TauP30IL transgenes) that received an intracerebroventricular injection of streptozotocin (icv-STZ, 3 mg/kg) or vehicle (saline) for 33 days. After serial behavioral tests, fecal short-chain fatty acid levels and AD-related pathology were assessed in these mice. Results Our findings show that intracerebroventricular injection of streptozotocin accelerated cognitive dysfunction associated with increasing levels of glycogen synthase kinase 3 beta (GSK3β) activity, tau protein phosphorylation at the T231 site (pT231), amyloid-β (Aβ) deposition, amyloid-β protein precursor (AβPP), β-site AβPP-cleaving enzyme (BACE1), gliosis, fecal propionic acid (PPA) levels and cognition-related neuronal loss and decreasing postsynaptic density protein 95 (PSD95) levels in 3 × Tg-AD mice. PS128 supplementation effectively prevented the damage induced by intracerebroventricular injection of streptozotocin in 3 × Tg-AD mice. Conclusions Based on the experimental results, intracerebroventricular injection of streptozotocin accelerates the progression of AD in the 3 × Tg-AD mice, primarily by increasing the levels of gliosis, which were mediated by the propionic acid and glycogen synthase kinase 3 beta pathways. PS128 supplementation prevents damage induced by intracerebroventricular injection of streptozotocin by regulating the propionic acid levels, glycogen synthase kinase 3 beta activity, and gliosis in 3 × Tg-AD mice. Therefore, we suggest that PS128 supplementation is a potential strategy to prevent and/or delay the progression of AD.

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