Caprylic Acid Improves Lipid Metabolism, Suppresses the Inflammatory Response and Activates the ABCA1/p-JAK2/p-STAT3 Signaling Pathway in C57BL/6J Mice and RAW264.7 Cells.

Objective: This study aimed to investigate the effects of caprylic acid (C8:0) on lipid metabolism and inflammation, and examine the mechanisms underlying these effects in mice and cells.
Methods: Fifty-six 6-week-old male C57BL/6J mice were randomly allocated to four groups fed a high-fat diet (HFD) without or with 2% C8:0, palmitic acid (C16:0) or eicosapentaenoic acid (EPA). RAW246.7 cells were randomly divided into five groups: normal, lipopolysaccharide (LPS), LPS+C8:0, LPS+EPA and LPS+cAMP. The serum lipid profiles, inflammatory biomolecules, and ABCA1 and JAK2/STAT3 mRNA and protein expression were measured.
Results: C8:0 decreased TC and LDL-C, and increased the HDL-C/LDL-C ratio after injection of LPS. Without LPS, it decreased TC in mice ( P < 0.05). Moreover, C8:0 decreased the inflammatory response after LPS treatment in both mice and cells ( P < 0.05). Mechanistic investigations in C57BL/6J mouse aortas after injection of LPS indicated that C8:0 resulted in higher ABCA1 and JAK2/STAT3 expression than that with HFD, C16:0 and EPA, and resulted in lower TNF-α, NF-κB mRNA expression than that with HFD ( P < 0.05). In RAW 264.7 cells, C8:0 resulted in lower expression of pNF-κBP65 than that in the LPS group, and higher protein expression of ABCA1, p-JAK2 and p-STAT3 than that in the LPS and LPS+cAMP groups ( P < 0.05).
Conclusion: Our studies demonstrated that C8:0 may play an important role in lipid metabolism and the inflammatory response, and the mechanism may be associated with ABCA1 and the p-JAK2/p-STAT3 signaling pathway.
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