The Effect Of Leflunomide On The NOD Mouse Model With Sj?gren's Syndrome

Objective To investigate the effect of leflunomide on hyposecretion of salivary gland and abnormal immunity in the NOD mouse with Sj?gren's syndrome(SS).Methods 28 NOD mice were randomly divided into four groups:preventive drug group(preventive administration at 8weeks),preventive control group(menstruum administration at 8weeks),therapeutic drug group(therapeutic administration at 16weeks)and therapeutic control group(menstruum administration at 16weeks).Salivary flow rate was measured after pilocarpine stimulation;After hematoxylin and eosin staining,the average number and area of infiltrating focus were compared;The percentage of CD3~+T,CD4~+T,CD8~+T,CD44~+CD62L~-CD4~+T,CD19~+B and CD138~+B cells in submandibular gland and spleen were detected by flow cytometry;The levels of serum inflammatory factors TNF-a,IL-17a and IL-6 were detected by CBA method.Results(1)Leflunomide improves the SS-like syndrome of NOD mouseThe salivary flow rate of NOD mouse in the prevention(t=-5.81,P<0.001)and treatment groups(t=-3.61,P=0.005)increased significantly.There was no significant difference between the prevention group and the treatment group(t=-0.06 P=0.954).(2)Leflunomide inhibits lymphocytic infiltration in submandibular gland and alleviates sialadenitisThe submandibular gland index in the treatment group decreased significantly(t=4.723,P<0.001),while that in the prevention group did not change significantly(t=1.36,P=0.204).The average number of lymphocytic focus in the prevention group(t=3.953,P=0.003)and the treatment group(t=4.94,P<0.001)were significantly decreased.The average infiltrating area of the prevention group(t=3.183,P=0.013)and the treatment group(t=2.352,P=0.043)was also significantly lower than that of the control group respectivly.(3)Leflunomide regulates lymphocyte subsets in submandibular glandThe CD4~+T(t=2.394,P=0.034)and CD44~+CD62L~-T(t=3.637,P=0.005)cells in submandibular gland of the preventive group were significantly decreased.In the treatment group,CD3~+T(t=2.789,P=0.015),CD4~+T(t=3.819,P=0.002),CD8~+T(t=2.225,P=0.046),CD44~+CD62L~-T(t=3.767,P=0.003),CD19~+B(t=5.132,P<0.001),CD138~+B(t=3.136,P=0.009)cells in submandibular gland were significantly down regulated.(4)Leflunomide regulates lymphocyte subsets in spleenThe CD3~+T(t=6.078,P<0.001),CD4~+T(t=2.307,P=0.039),CD8~+T(t=4.258,P=0.002),CD44~+CD62L~-T(t=3.283,P=0.007),CD19~+B(t=5.881,P<0.001),CD138~+B(t=4.305,P=0.001)cells were significantly decreased in the spleen of the preventive drug group.The CD3~+T(t=2.756,P=0.022),CD4~+T(t=2.391,P=0.038),CD19~+B(t=4.226,P=0.002),CD138~+B(t=4.456,P=0.002)in the spleen of the treatment group were also significantly decreased.(5)Leflunomide inhibits the level of inflammatory cytokines in serumThe serum level of TNF-?in the preventive group(t=4.56,P<0.001)was significantly decreased.The serum level of IL-17A in the preventive group(t=4.152,P=0.001)and the therapeutic group(t=3.357,P=0.007)decreased significantly.There was no significant difference in the level of IL-6 between the prevention group(t=2.245,P=0.051)and the treatment group(t=0.594,P=0.563).Conclusion This study suggests that leflunomide can prevent and improve salivary gland hypofunction and inhibit immune activation in NOD mice,providing a theoretical basis for evaluating leflunomide in the treatment of Sjogren's syndrome.