Protective Effect and Mechanism of Docosahexaenoic Acid-Enriched Phospholipids and Eicosapentaenoic Acid-Enriched Phospholipids on Lipopolysaccharide-Induced Acute Liver Injury in Mice

To investigate the protective effect and mechanism of docosahexaenoic acid-enriched phospholipids (DHA-PL) and eicosapentaenoic acid-enriched phospholipids (EPA-PL) on lipopolysaccharide (LPS)-induced acute liver injury.

DHA-PL and DHA-PL were obtained from the eggs of Sthenoteuthis oualaniensis and the body wall of Cucumaria frondosa, respectively. C57BL/6 male mice were randomly divided into four groups, i.e. control group, LPS-induced model group, LPS + DHA-PL group and LPS + EPA-PL group. The mice in the LPS + DHA-PL and LPS + EPA-PL groups were given DHA-PL and EPA-PL via the intragastric route at 400 mg/kg m_b on a daily basis for 28 days, respectively, while those in the control and model groups were gavaged with normal saline. The mice in the control group were injected with normal saline intraperitoneally at day 29, while those in the other groups were injected with LPS (10 mg/kg m_b) at an injection volume of 10 mL/kg m_b to establish a model of acute liver injury. The pathological changes of liver tissues were observed by hematoxylin-eosin (HE) staining. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities were measured. The transcriptional levels and contents of tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 in liver tissues were detected by real-time quantitative polymerase chain reaction (PCR) and enzyme linked immunosorbent assay (ELISA), respectively. The phosphorylation levels of mitogen-activated protein kinases (MAPKs) such as extracellular regulated protein kinases 1/2 (ERK1/2), c-Jun N-terminal kinase (JNK), p38, and nuclear factor (NF)-κB p65 were determined by Western blotting.

DHA-PL and EPA-PL intervention effectively alleviated LPS-induced acute liver injury and reduced hepatic index and serum ALT and AST activities, decreased the hepatic mRNA expression and contents of TNF-α, IL-1β and IL-6, and down-regulated the phosphorylation of ERK1/2, JNK, p38 and NF-κB p65.

DHA-PL and EPA-PL can prevent LPS-induced acute liver injury in mice, and the mechanism may depend on regulation of the MAPKs and NF-κB signaling pathways.