Demethylzeylasteral (T-96) Treatment Ameliorates Mice Lupus Nephritis Accompanied by Inhibiting Activation of NF-κB Pathway

BACKGROUND: Inflammation plays a vital role in the pathogenesis in lupus nephritis (LN), which is largely attributable to the activation of nuclear factor kappa B (NF-κB) signal pathway. NF-κB up-regulates pro-inflammatory mediators, such as TNF-α, cyclo-oxygenase-2 (COX-2) and ICAM-1, and promotes macrophage infiltration into renal tissue, further inducing the progression of LN. Over the past 30 years, research has demonstrated that Tripterygium wilfordii Hook F (TWHF) possesses potent anti-inflammatory and immunosuppressive activities, and that demethylzeylasteral (T-96), an extract of TWHF, may be one of the responsible compounds. Here, we investigate the pharmacodynamic role and therapeutic mechanism by which T-96 suppresses inflammation and reduces renal pathology in the lupus-prone MRL/lpr mice. METHODS: Forty-eight MRL/lpr mice were equally randomly divided into 6 groups (1.2, 0.6 or 0.3 mg/10g T-96, 0.022 pills/10g kang lang chuang san (one of Traditional Chinese herb as positive control), 0.125 mg/10g prednisone and 0.1 ml/10g normal saline as the LN disease control group). Also, eight WT C57BL/6 mice were used as normal control. After treatment by gavage with 0.10 ml/10g/day volumes for 8 weeks, all mice were sacrificed and renal tissues were collected. The amount of 24 h proteinuria and the levels of anti-dsDNA antibody in serum were assessed respectively at weeks 0, 4 and 8. Inflammation, cytokines and NF-κB levels were assessed by histological examinations, immunohistochemical analyses and Western blot analyses. RESULTS: In comparison with untreated MRL/lpr mice, mice treated with 1.2 and 0.6 mg/10g of T-96 showed a significant improvement in 24 h proteinuria and the levels of anti-dsDNA antibody in serum. In addition, T-96 reduced the secretion of pro-inflammatory mediators such as TNF-α, COX-2 and ICAM-1, and the infiltration of macrophages in renal tissue. Moreover, T-96 significantly suppressed phosphorylations of cytoplasmic IKK and nuclear p65. CONCLUSION: This study suggests that T-96 exhibits reno-protective effects in LN accompanied by inhibiting the activation of NF-κB, reducing the downstream pro-inflammatory mediators and thus restricting macrophage infiltration. Because of these potent properties, T-96 should be considered as a promising therapeutic drug for LN.