Abstract: 【Abstract】Objective To explore the regulation effect of 1,25-dihydroxy vitamin D3 (1,25-OH2D3) on interleukin-4 (IL-4) in rat with IgA nephropathy. Method Fifty-two Wistar rats were divided into group A (normal control group), group B (no intervention group), group C (prednisone treatment group), group D (1,
25-OH2D3 treatment group), and group E (prednisone + 1,25-OH2D3 treatment group). Urine protein/24 h, IL-4 levels in spleen and lymph nodes were assayed. Result ①Urine protein/24 h was 7.03±0.99, 51.49± 3.04, 12.15±0.75, 23.0±2.27, and 9.99±0.79 mg/24 h in group A, B, C, D, and E, respectively. After the treatment, the decrease of urine protein/24 h was more in groups C, D and E than in group B (P＜0.05), and was more in group E than in groups C and D (P＜0.05). ② IL-4 level in spleen was 1.428±0.60, 5.10±0.08, 2.93± 0.13, 4.56±0.19, and 1.44±0.56% in group A, B, C, D, and E, respectively. ③ IL-4 level in lymph nodes was 1.50±0.13, 15.4±3.11, 2.74±0.29, 6.55±0.66, and 2.32±0.34% in group A, B, C, D, and E, respectively. After the treatment, the decrease of IL-4 levels in spleen and lymph nodes were more in groups C, D and E than in group B (P＜0.05), and were more in group E than in groups C and D (P＜0.05). Conclusion 1,25-OH2D3 treatment may down-regulate IL-4 expression and thus affect the regulation by Th2 lymphocytes in rats with IgA nephropathy.

Key words: 1,25- dihydroxy Vitamin D3, IgA nephropathy, Interleukin-4