RESUMO
Objective To investigate the mechanism of pioglitazone preventing diabetes and the role of nuclear factor of actived T cells (NFAT) on non-obese diabetic(NOD) mice .Methods (1)Female NOD mice at 4 weeks of age were randomly divided into pioglitazone group(n=21) and control group(n=21) .The accumulative diabetes incidence was followed-up to 30 weeks of age in each group of NOD mice .(2)Pancreas were removed from NOD mice at 12 weeks of age in each group(n=15) to score insulitis se-verity by routine HE staining .IL-4 ,IFN-γand peroxisome proliferator-activated receptor γ(PPARγ) mRNA levels in spleens were tested by RT-PCR .IL-4 and IFN-γlevels in sera ,the activity of PPARγand NFATc1 nuclear protein in spleens were measured by enzyme linked immunosorbent assay (ELISA) .Results (1) At 15 weeks of age ,the diabetes incidence was 4 .76% in pioglitazone group ,and 33 .33% in control group(P0 .05) .(2) At 12 weeks of age ,the insulitis score in pioglitazone group was lower than that in control group[(1 .79 ± 0 .75) vs .(2 .38 ± 0 .66) ,P<0 .05] .(3) IFN-γ mRNA level in pioglitazone group was lower than that in control group[(0 .16 ± 0 .07) vs .(0 .53 ± 0 .26) ,P<0 .05] ,and PPARγmRNA level in pioglitazone group was higher than that in control group(0 .91 vs .0 .25 ,P<0 .05) .(4)IFN-γ level in pioglitazone group was lower than that in control group [(561 .05 ± 78 .61)pg/mL vs .(666 .43 ± 28 .42)pg/mL ,P<0 .05] .(5)At 12 weeks of age ,the spleen PPARγnuclear protein activity in pioglitazone group was higher than that in control group [(0 .05 ± 0 .01) vs .(0 .02 ± 0 .01) ,P<0 .05)] ,and NFATc1 nuclear protein activity was low-er than that in control group[(0 .23 ± 0 .04) vs .(0 .33 ± 0 .04) ,P<0 .05] .Conclusion Pioglitazone could activate PPARγ nuclear protein ,inhibit activity of NFATc1 nuclear protein ,downregulate IFN-γ,diminish Th cells deviating to Th1 ,and sequently prevents insulitis and diabetes onset in NOD mice .