Lycium barbarum polysaccharide improves traumatic cognition via reversing imbalance of apoptosis/regeneration in hippocampal neurons after stress

Abstract

Aims: Previous studies in our laboratory have demonstrated the increased neuronal apoptosis in the hippocampus and abnormal hippocampal morphology after severe stress, which directly correlates to the pathogenesis of post-traumatic stress disorder (PTSD). This study aims to investigate the effects of Lycium barbarum polysaccharide (LBP) on intrusive memory of posttraumatic stress in rats, and to analyze the mechanism of regeneration/apoptosis balance in the hippocampal neurons.

Main methods: The experimental rats received 20 inescapable electric foot shocks in an enclosed box for six times in three days. The rats were treated by intragastric administration of LBP (20mg/kg/day) for 3 days before stress in the stress plus prophylactic group, and for 28 days after stress in the stress plus therapeutic group. The emotion, intrusive memory-related behavior (freezing, open field, pain latency, spatial cognition), hippocampus cell morphology, and relation of neurogenesis and apoptosis in dental gyrus of the hippocampus were observed. The hippocampus volume was evaluated by stereology. Meanwhile, the neurogenesis and apoptosis were analyzed with 5-bromo-2'-deoxyuridine and terminal deoxylnucleotidyl transferase mediated-dUTP nick end labeling (TUNEL) method.

Key findings: The treatment of LBP in pre-stress and post-stress had obvious beneficial effect on the behaviors and neurogenesis. The stressed rats showed improvement of intrusive memory related cognition defect, alleviation of the apoptosis in the hippocampus and recovery for the neurogenesis, which was related to the hippocampus volume after LBP treatment.

Significance: LBP treatment might effectively improve the traumatic cognition defect induced by severe stress and be useful for the intrusive memory-related cognition recovery.

Keywords: (5alpha, 6alpha, 7alpha, 22R)-5-hydroxy-6, 7: 22, 26-diepoxyergosta-2, 24-diene-1, 26-dione (PubChem CID: 14236711); 56973-41-2 (PubChem CID: 14236711); Apoptosis; Hippocampus; Hypothalamus–pituitary–adrenal (HPA) axis; Intrusive memory; Lycium barbarum polysaccharide (LBP); Lycium substance B (PubChem CID: 14236711); Neurogenesis; Posttraumatic stress; UNII-9YU877VU8K (PubChem CID: 14236711); Withanolide B (PubChem CID: 14236711).