Abstract:

Objective

To investigate the effects and mechanisms of atorvastatin on macrophage polarization in high-fat diet-induced metabolic-associated fatty liver disease （MAFLD）in New Zealand rabbits.

Methods

Single-cell datasets from healthy individuals and MAFLD patients were downloaded from the GEO database. Fifteen male New Zealand rabbits were divided into normal control group （NCG）， high-fat diet model group （MCG）， and high-fat diet +atorvastatin treatment group （PCG）. The rabbits in NCG were fed with standard diet， while those in other groups were fed with high-fat diet. Atorvastatin was administered at a dose of 4 mg/kg/day.After 8 weeks， Oil Red O staining was used to assess the differences in hepatic lipid deposition among groups. Western blot was performed to measure the protein expression levels of Toll-like receptor 4/ nuclear factor kappa B （TLR4/NF-κB） in liver tissues. Flow cytometry was used to determine the proportions of macrophage subtypes in peripheral blood. ANOVA-test was used for comparisons among multiple groups， and the Bonferroni method was used for pairwise comparisons between groups.

Results

Single-cell data analysis revealed that TLR4 is expressed across all macrophage subtypes in MAFLD patients and associated with M2 macrophage polarization. Compared to the NCG group， N the hepatic lipid depositionand the expression levels of TLR4 （0.68 ± 0.08 vs 0.37 ± 0.06），NF-κB proteins （1.81 ± 0.14 vs 1.27 ± 0.13） were significantly elevated in the MCG group after 8 weeks of high-fat diet feeding （P ＜ 0.001）， which could be restored after atorvastatin treatment（TLR4 protein 0.58 ± 0.08 vs 0.68 ± 0.08， NF-κB protein expression 1.60 ± 0.14 vs 1.81 ± 0.14） .Compared with MCG group， theproportion of M2 macrophages （0.42 ± 0.05）% vs （2.22 ± 0.16）%in peripheral blood was increased in PCG group （P ＜ 0.001）.

Conclusion

Peripheral blood macrophage subtypes are associated with MAFLD progression. Atorvastatin reduces hepatic lipid deposition in high-fat diet-induced New Zealand rabbits by modulating the TLR4/NF-κB signaling pathway and regulating M1/M2 macrophage polarization.

Key words: Metabolic-associated fatty liver disease, Toll-like receptor, Macrophage polarization, NF-κB