Effects of Lycium barbarum polysaccharides with different molecular weights on function of RAW264.7 macrophages

The present study was aimed at investigating the effects of four LBP fractions with different molecular weights (MWs), designated LBP2, LBP3, LBP4 and LBP5, on RAW264.7 macrophages function. Results showed that LBP fractions could significantly enhance the expression of CD86 and MHC-II molecules on RAW264.7 macrophages. LBP3, LBP4 and LBP5 could enhance the production of ROS, NO, TNF-α and IL-6, and the phagocytosis of RAW264.7 macrophages. LBP2 with an MW of larger than 350 kDa could only enhance the secretion of TNF-α. LBP3 enhanced the RAW264.7 macrophages function in a dose-dependent manner and also enhanced the iNOS mRNA expression in the cells. These results demonstrated that the immunomodulatory activity of LBP on RAW264.7 macrophages was closely related to its MW. It indicated that fractions with an MW smaller than 350 kDa were the main active fractions of LBP in enhancing macrophages function.