ABSTRACT
OBJECTIVE To investigate the therapeutic effect and side effect of ibrutinib long-term treatment in systemic lupus erythematosus (SLE) model mice induced by pristane. METHODS Female 6-week old BALB/c mice were ip given pristane 0.5 mL once for SLE induction. Four weeks later, the SLE model mice were divided into three groups based on the body mass and serum level of anti-double-strand DNA (DS-DNA) antibody and treated with 1%methylcellulose (model control group, ig), ibrutinib (30 mg·kg-1, ig) or prednisone (10 mg·kg-1, ig), respectively, once daily for 28 weeks. Every 4 weeks, body mass of each mouse was measured. Autoantibodies against DS-DNA, single-strand DNA (SS-DAN), and histone were tested by ELISA. The incidence of lupus arthritis and clinical score of inflammation and edema were recorded and graded. Biochemical analysis of urea protein, serum urea nitrogen and creatinine was used to evaluate kidney function. Mice were euthanized post 28 weeks of dosing. Inter-leukin-6 (IL-6), interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) were tested by ELISA. The heart, liver, spleen, lung, and kidney were collected and weighed for organ relative mass calculation. Biochemical analysis of serum glutamic-pyruvic transaminase (GPT), glutamic-oxal(o)acetic transaminase (GOT) and alkaline phosphatase (ALP) was used to evaluate liver function. Hind feet were collected for HE staining and pathological scoring to observe renal injury and inflammation. Immunohistochemical staining was used to study IgG immune complexes deposition in kidneys of lupus. RESULTS Compared with normal control group, autoantibodies (anti-DS-DNA, anti-SS-DNA and anti-histone antibodies), renal function indexes (serum creatinine, urea nitrogen and urine protein), and cytokines (IL-6, IFN-γ and TNF-α) levels in model group were significantly increased (P<0.01). The model group mice had obvious clinical symptoms of arthritis (P<0.01), serious inflammation cell invasion (P<0.01), and the mass of kidneys and spleen increased significantly (P<0.01). Compared with model group, after 28 weeks of treatment, ibrutinib decreased the level of anti-DS-DNA, anti-SS-DNA and anti-histone antibodies (P<0.01), decreased the lupus arthritis score (P<0.01) and the morbidity of arthritis, reduced the level of cyto-kines IL-6, IFN-γand TNF-α(P<0.01), reduced the level of serum creatinine, serum urea nitrogen and urine protein (P<0.01), improved pathological symptoms of hind feet such as inflammation, cartilage destruction, bone resorption and pannus (P<0.01), alleviated renal tissue inflammatory cell invasion and the immune-complex precipitation, and reduced the mass of organs (spleen and kidneys, P<0.01) and the level of liver function (GPT and ALP, P<0.01). CONCLUSION Long-term treatment with ibrutinib has therapeutic effect on the model mice of SLE, and has no obvious side effect.