Chitooligosaccharide from Pacific White Shrimp Shell Chitosan Ameliorates Inflammation and Oxidative Stress via NF-κB, Erk1/2, Akt and Nrf2/HO-1 Pathways in LPS-Induced RAW264.7 Macrophage Cells

Chitooligosaccharide (COS), found in both insects and marine sources, has several bioactivities, such as anti-inflammation and antioxidant activities. However, the mechanism of shrimp shell COS on retardation of inflammatory and antioxidant effects is limited. Therefore, the aim of this study is to examine the mechanism of the aforementioned activities of COS in LPS-activated RAW264.7 macrophage cells. COS significantly improved cell viability in LPS-activated cells. COS at the level of 500 µg/mL could reduce the TNF-α, NO and IL-6 generations in LPS-activated cells (p < 0.05). Furthermore, COS could reduce ROS formation, NF-κB overactivation, phosphorylation of Erk1/2 and Akt and Nrf2/HO-1 in LPS-exposed cells. These results indicate that COS manifests anti-inflammatory activity and antioxidant action via NF-κB, Erk1/2, Akt and Nrf2/HO-1 signaling with an increasing relevance for inflammatory disorders.

Oral Administration of Ethanolic Extract of Shrimp Shells-Loaded Liposome Protects against Aβ-Induced Memory Impairment in Rats

Alzheimer's disease is characterized by a progressive loss of memory and cognition. Accumulation of amyloid-beta (Aβ) in the brain is a well-known pathological hallmark of the disease. In this study, the ethanolic extract of white shrimp (Litopenaous vannamei) shells and the ethanolic extract-loaded liposome were tested for the neuroprotective effects on Aβ_1-42-induced memory impairment in rats. The commercial astaxanthin was used as a control. Treatment with the ethanolic extract of shrimp shells (EESS) at the dose of 100 mg/kg BW showed no protective effect in Aβ-treated rats. However, treatment with an EESS-loaded liposome at the dose of 100 mg/kg BW significantly improved memory ability in Morris water maze and object recognition tests. The beneficial effect of the EESS-loaded liposome was ensured by the increase of the memory-related proteins including BDNF/TrkB and pre- and post-synaptic protein markers GAP-43 and PSD-95 as well as pErk1/2/Erk1/2 in the cortex and hippocampus. These findings indicated the neuroprotective effects of the EESS-loaded liposome on Aβ-induced memory impairment in rats. It produced beneficial effects on learning behavior probably through the function of BDNF/TrkB/pErk1/2/Erk1/2 signaling pathway and subsequently the upregulation of synaptic proteins. The present study provided evidence that the neuroprotective property of the ESSE-loaded liposome could be a promising strategy for AD protection.