Ingestion of Lactobacillus strain reduces anxiety and improves cognitive function in the hyperammonemia rat

• DOI: 10.1007/s11427-014-4615-4
• Publication Date: 2014-02-19T09:21:07Z
• Authors: Jia Luo; Tao Wang; Shan Liang; Xu Hu; Wei Li; Feng Jin
• Keywords: cognition; Male; 0301 basic medicine; Serotonin; hyperammonemia; Interleukin-1beta; 610; Nitric Oxide Synthase Type II; Enzyme-Linked Immunosorbent Assay; Anxiety; Dinoprostone; neuroinflammation; Rats, Sprague-Dawley; 03 medical and health sciences; Environmental Science(all); Animals; Humans; Hyperammonemia; 0303 health sciences; Agricultural and Biological Sciences(all); Biochemistry, Genetics and Molecular Biology(all); Probiotics; Brain; Hydroxyindoleacetic Acid; anxiety; 6. Clean water; serotonin; Rats; 3. Good health; Disease Models, Animal; Lactobacillus; probiotics; Hepatic Encephalopathy; Inflammation Mediators; Cognition Disorders

Evidence suggests that the hyperammonemia (HA)-induced neuroinflammation and alterations in the serotonin (5-HT) system may contribute to cognitive decline and anxiety disorder during hepatic encephalopathy (HE). Probiotics that maintain immune system homeostasis and regulate the 5-HT system may be potential treatment for HA-mediated neurological disorders in HE. In this study, we tested the efficacy of probiotic Lactobacillus helveticus strain NS8 in preventing cognitive decline and anxiety-like behavior in HA rats. Chronic HA was induced by intraperitoneal injection of ammonium acetate for four weeks in male Sprague-Dawley rats. HA rats were then given Lactobacillus helveticus strain NS8 (10(9) CFU mL(-1)) in drinking water as a daily supplementation. The Morris water maze task assessed cognitive function, and the elevated plus maze test evaluated anxiety-like behavior. Neuroinflammation was assessed by measuring the inflammatory markers: inducible nitric oxide synthase, prostaglandin E2, and interleukin-1 β in the brain. 5-HT system activity was evaluated by measuring 5-HT and its metabolite, 5-HIAA, and the 5-HT precursor, tryptophan. Probiotic treatment of HA rats significantly reduced the level of inflammatory markers, decreased 5-HT metabolism, restored cognitive function and improved anxiety-like behavior. These results indicate that probiotic L. helveticus strain NS8 is beneficial for the treatment of cognitive decline and anxiety-like behavior in HA rats.