Abstract: Objective Explore the mechanism of 1α,25-dihydroxyvitaminD3 regulation on Th1 cells in IgA nephropathy rats. Method The model of 32 IgA nephropathy rats were randomly divided into prednisone treatment group, 1α,25- dihydroxyvitaminD3 treatment group,prednisone + 1α,25- dihydroxyvitaminD3 treatment group and non treatment group.At the same time,we set up the normal control group.24 hours urine protein,serum creatinine value and IFN- γwere measured in each group. Results ①The level of 24-hour urine protein in group A,B,C,D and E, are respectively 7.03±0.99mg/d,51.49±3.04mg/d,12.15±0.75mg/d,23.0± 2.27mg/d and 9.99±0.79mg/d, in which the group A,C,D and E decreased significantly compared with the group B (F=47.778, P<0.05). ②The level of IFN-γin spleen of group A,B,C,D and E are respectively 0.64%± 0.05%,3.63%±0.22%,2.11%±0.13%,1.33%±0.10% and 0.97%±0.17%.The level of IFN-γin Lymph Node of
group A,B,C,D and E are respectively 2.13%± 0.42%,17.32%± 0.65%,8.44%± 0.38%,6.39%± 0.57% and 3.01%±0.27%, among the group A,C,D and E decreased significantly compared with the group B(F=479.381，P＜0.05). Conclusion 1α,25-dihydroxyvitaminD3 can reduce the level of urinary protein and IFN-γ in IgA nephropathy rats.

Key words: 1α,25-dihydroxyvitaminD3, IgA nephropathy, IFN-γ