Effect of combined methotrexate and cyclophosphamide therapy on the expression of B cell activation factor belonging to the TNF family in the salivary glands of mice with induced Sj(o)gren's syndrome / 中华风湿病学杂志

ABSTRACT

Objective To investigate the effect of combination therapy by observing the salivary glands function and related organ pathology after given methotrexate (MTX) and cyclophosphamide (CTX) intermittently in induced mice model of Sjogren's syndrome (SS). To further explore the synergistic effect of combination therapy by detecting the immunological regulatory factor B cell activation factor belonging to the TNF family (BAFF) expression. Methods The ingredients of Lewis rat's exocrine glands homogenate were injected into female C57BL/6 mice to set up the mice model of SS. After established the SS mice model successfully, they were randomly divided into six SS model group, including low-dose MTX treatment group (0.02 mg/w), high-dose MTX treatment group (0.06 mg/w), CTX pause treatment group (1.2 mg/3 w), CTX alternate day treatment group (0.6 mg/2 d), MTX+CTX combination treatment group (MTX 0.02 mg/3 w+ CTX 1.2 mg/3 w). Treatment effects were assessed both clinically and histologically. Results Eighteen weeks after the first treatment, the improvement of the salivary secretion of the CTX alternate day treatment group and MTX+CTX combination treatment group were higher than other groups, which showed statistically significant difference (P<0.01). Compared with the SS model control group, HE staining showed that the lymphocytic infiltration of exoerine glands was decreased in the treatment group. In the CTX alternate day treatment group and MTX+CTX combination treatment group, few amount of inflammatory cell infiltration were found, and the expression intensity of BAFF mRNA and protein were decreased markedly in salivary gland than others by RT-PCR and immunohistochemistry assay (P<0.01). Conclusion MTX and CTX can inhibit lymphocytic infiltration of the salivary glands, inhibit BAFF transcriptional level and production of BAFF protein, leading to an increase of fluid production. It suggests that modulation of signaling via BAFF pathways may be a mechanism of action. MTX and CTX combination therapy is more effective than single-agent therapy. The inhibitory effects of MTX and CTX on BAFF-mediated inflammatory pathways are primarily synergistic.