Effect of Betulic Acid on RAGE/NF-κB/iNOS Signaling Pathway Expression in Steatosis Cell / 中国实验方剂学杂志

ABSTRACT

Objective:To investigate the effect of betulic acid(BA) on steatosis LO2 cells. Method:LO2 cells were intervened with BA at different gradient concentrations (0, 10, 20, 40, 80, 160, 250 μmol·L-1) for 24 hours. methyl thiazolyl tetrazolium(MTT) staining was used to observed cell viability to determine the final concentration of BA. The cells were divided into control, model, dimethylsulfoxide (DMSO) and BA groups, as well as BA groups intervened with low, middle and high concentrations. First, model, DMSO and BA group's cells were cultured in 10% Lipid Mix 1 medium for 24 hours to establish a nonalcoholic fatty liver model. Then, DMSO group and low, medium and high-concentration groups were separately cultured with 0.1%DMSO medium and 20, 40, 80 μmol·L-1 BA medium for 24 hours. And control and model groups were cultured in drug-free medium for 24 hours. Oil red O staining and Nile red staining were used to observe the intracellular lipid droplets. Immunofluorescence was used to detect the protein expression of inducible nitric oxide synthase (iNOS). Western blot was used to detect the protein expression levels of receptor for advanced glycation end-products (RAGE), nuclear factor κB p65 (NF-κB p55) and iNOS. Result:BA within the concentration of 80 μmol·L-1 had no significant toxicity on LO2 cells. Compared with control group, the intracellular lipid droplets were significantly increased in the model group, and the expressions of oxidative stress-related proteins RAGE, NF-κB p65 and iNOS also increased significantly(P<0.05). Compared with model group, the intracellular lipid droplets in DMSO group were similar to those in model group, with no significant difference in the three protein expressions between the two groups. However, the intracellular lipid droplets deposition in the BA group was significantly decreased. And the expressions of RAGE, NF-κB p65 and iNOS proteins in high-concentration BA group were significantly decreased(P<0.05, P<0.01). Conclusion:BA can significantly improve the intracellular fat deposition in LO2 cells, which was probably related to the inhibition of the expressions of oxidative stress-related proteins RAGE, NF-κB p65 and iNOS.