Rapamycin alleviates renal damage in mice with systemic lupus erythematosus through improving immune response and function.

This study aimed to explore the therapeutic effect and mechanism of rapamycin (RAPA) on systemic lupus erythematosus (SLE) in BALB/C mice induced by pristane. The mice were randomly divided into 5 groups (n = 6): control, model, saline, RAPA (1 mg/kg) and RAPA (2 mg/kg). All groups were injected with pristane except control. HE staining revealed 1 mg/kg and 2 mg/kg RAPA treatments obviously alleviated pathological changes in the kidney of SLE mice such as glomeruli enlargement, hyperplasia of mesangial cells, epithelial and endothelial cells, infiltration of inflammatory cells, and edema-like degeneration of renal tubules. Compared with control group, body weights and anti-ribosomal P-protein antibody (ARPA) level of the mice in model group and saline group decreased (P < 0.05), while immune complex deposition and levels of anti-dsDNA antibody, anti-smRNP antibody and urine protein in model group and saline group increased (P < 0.05). However, compared with model group and saline group, body weights of the mice in RAPA (1 mg/kg) group and RAPA (2 mg/kg) group increased (P < 0.05), while immune complex deposition and levels of anti-dsDNA antibody, anti-smRNP antibody, ARPA, and urine protein in RAPA (1 mg/kg) group and RAPA (2 mg/kg) group decreased (P < 0.05). Compared with control group, the proportion of dentritic cells (DC) in the kidney and peripheral blood decreased while the proportion of Th1, Th2 and Th17 cells in the spleen, kidney and peripheral blood increased in model group and saline group (P < 0.05). Compared with model group and saline group, 1 mg/kg and 2 mg/kg RAPA treatments boosted the proportion of DC in the kidney and peripheral blood, reduced the proportion of Th1 and Th17 cells in the spleen, kidney and peripheral blood, and lessened the proportion of Th2 cells in the kidney and peripheral blood (P < 0.05). In conclusion, RAPA alleviated renal damage in SLE mice through improving immune response and function.