Effect Of Hydroxychloroquine On Disease Activity And Gut Microbiota In Systemic Lupus Erythematosus Mice

Objective:To investigate the effects of hydroxychloroquine on systemic lupus erythematosus(SLE)mice(genotype B6.NZMSle1 / 2/3,TC mice)associated with disease severity,immune system and intestinal flora.Methods:20-week-old female TC mice were randomly divided into two groups.The experimental group was treated with 10 mg /(kg · d)hydroxychloroquine by gavage,and the control group was treated with 10 mg /(kg · d)saline for gavage for 8 weeks.The weight changes and skin symptoms of the two groups of mice were observed and recorded weekly.Enzyme-linked immunosorbent assay(ELISA)was used to detect the serum anti-dsDNA antibody titer level,interferon ?(IFN-?)and B cell activation factor(BAFF)levels.Hematoxylin and eosin staining(HE)was used to detect the pathological changes of the kidneys in mice,and immunofluorescence was used to detect the deposition of immune complexes in the kidneys of mice.Flow cytometry was used to detect the proportion of spleen lymphocytes in mice.Collect mouse feces for metagenomic sequencing,and analyze the diversity and difference of fecal microbial flora.Resullts:The skin hair loss and skin damage of the TC mice in the experimental group treated with hydroxychloroquine were significantly lower than those in the control group(P<0.05).HE staining of the kidney showed that the glomeruli increased in the experimental group.The increase of large and renal interstitial cells and the stenosis of renal vessels were significantly lower than that of the control group.Immunofluorescence staining of the kidney showed that the deposition of IgG and C3 in the kidney of the experimental group was significantly lower than that of the control group.Flow cytometry analysis showed that the proportion of spleen plasma cells in the experimental group was significantly higher than that in the control group(P<0.05),and there was no significant difference in the proportion of plasmablasts between the two groups.Compared with TC mice in normal saline group,Bacteroidetes,Firmicutes,Proteobacteria,Verrucomicrobia,Proteobacteria accounted for a higher proportion of intestinal flora of TC mice in HCQ treatment group.There is no statistically significant difference in relative abundance of Verrucobacterium spp.(P>0.05).The relative abundance of Deinococcus-Thermus,which accounts for a small proportion,increases significantly,the difference is statistically significant(P<0.05).There were no significant differences in the analysis of alpha diversity and beta diversity between the two groups of TC mice.Conclusion:Hydroxychloroquine effectively reduced the disease activity of TC mice,It has a regulatory effect on the ratio of spleen lymphocytes of TC mice and the number distribution of intestinal flora of TC mice at various classification levels.