Safety of rituximab on testicles, a double-blindedcontrolled trial in mice

Objectives: Rituximab (RTX) is a biologic agent used for rheumatic and autoimmune disorders. RTX is a drug indicated for the treatment of patients with refractory rheumatoid arthritis patients who have not responded to nonbiological therapy and one or more anti-tumor necrosis factor-α drugs. The purpose of this trial was to investigate the RTX effects on testes in BALB/c mice by histology. Materials and Methods: A total of 20 mice were divided into two groups. Ten mice were subjected to weekly subcutaneous (SC) injection of RTX (0.31 mg/25 g body weight, in a final volume of 0.03 ml normal saline [NS] solution) for only the first 4 weeks. For the control group, ten mice were subjected to weekly SC injection of 0.03 ml NS solution. At the 10th week after first SC injection, mice were sacrificed, and histological analysis of tests was performed. Results: One out of ten mice died in the RTX-tested group; meanwhile, the remaining mice and the NS-tested group mice showed no abnormal histological findings. Conclusion: This is the first experimental animal trial which demonstrated that RTX treatment may not elicit testicular toxicity.