ABSTRACT
ObjectiveTo investigate the mechanism of Lycium barbarum polysaccharides （LBP） in promoting the activation of RAW264.7 macrophages. MethodRAW264.7 macrophages were stimulated with LBP at different concentrations （50， 100， 200 mg·L-1）， and those stimulated with lipopolysaccharide （LPS） at 100 μg·L-1 and galactose （Gal） at 100 mg·L-1 as positive controls. After 24 h of LBP stimulation， the cell counting kit-8 （CCK-8） was used to detect the survival rate of RAW264.7 macrophages treated with LBP （0， 50， 100， 200， 400， 800 mg·L-1）. The levels of interleukin-6 （IL-6） and interleukin-12 （IL-12） in cell culture supernatant were detected by enzyme-linked immunosorbent assay （ELISA）. The protein and mRNA expression of p38 mitogen-activated protein kinase （MAPK）， extracellular signal-regulated kinase （ERK）， c-Jun N-terminal kinase （JNK）， and nuclear factor κB （NF-κB） in Toll-like receptor 4 （TLR4）/Toll-like receptor 2 （TLR2）/macrophage galactose-type lectin （MGL） pathway of RAW264.7 macrophages was detected by Real-time fluorescence-based quantitative polymerase chain reaction （Real-time PCR） and Western blot. ResultCCK-8 results showed that compared with the results in the blank group， the survival rate of RAW264.7 macrophages decreased in the 400， 800 mg·L-1 LBP groups （P<0.05）. ELISA results showed that compared with the blank group， 50 mg·L-1 LBP could promote the secretion of IL-12 in RAW264.7 macrophages （P<0.01）. Compared with the blank group， 100 mg·L-1 LBP and 200 mg·L-1 LBP could promote the secretion of IL-6 in RAW264.7 macrophages （P<0.05， P<0.01）. Western blot results showed that compared with the blank group， the LBP groups （50， 100， 200 mg·L-1） enhanced protein expression levels of MAPK key molecules （p-p38 MAPK， p-ERK， p-NF-κB， and p-JNK） in TLR4， TLR2， and MGL pathways （P<0.05， P<0.01）. Compared with the model group， the 200 mg·L-1 LBP group could promote the expression level of p-NF-κB protein in RAW264.7 macrophages （P<0.01）. Real-time PCR results showed that compared with the blank group， the LBP groups （50， 100， and 200 mg·L-1） enhanced the mRNA expression levels of MAPK key molecules （p38 MAPK， ERK， NF-κB， and JNK） in TLR4 and TLR2 pathways （P<0.05， P<0.01）. Compared with the model group， the 50 and 200 mg·L-1 LBP groups could promote the mRNA expression levels of JNK and ERK2 in RAW264.7 macrophages （P<0.05， P<0.01）. ConclusionLBP can regulate the activation of RAW264.7 macrophages and participate in the immune response through the TLR2/TLR4/MGL pathway.