【Animal modeling】-Optimization of dose-response relationship between N-ethyl-N-nitrosourea and cyclophosphamide in pig-a gene mutation test in rats

  OBJECTIVE: To study the effect of different doses of N-ethyl-N-nitrosourea (ENU) and cyclophosphamide (CP) on the deletion rate of ankyrin CD59 in peripheral blood red blood cells of SD rats, and to optimize the Pig-a gene mutation test Detection method.

  Methods: SD rats were randomly divided into 4 groups according to body weight and peripheral blood RBC CD59-, namely vehicle control group, CP 40 mg/kg administration group, ENU 10 mg/kg administration group and ENU 40 mg/kg administration group Groups of 6 animals in each group were intraperitoneally injected, and the vehicle control group was injected with PBS solution. Weighing and blood collection were performed before and 7, 14, 21, 28, 42, and 56 days after exposure, and the incidence of RBC CD59- in peripheral blood was detected by flow cytometry.

  Results: Compared with the vehicle control group, the ENU 10 mg/kg administration group and the ENU 40 mg/kg administration group had no significant difference in body weight and body weight gain at each time point, and the CP 40 mg/kg administration group at each time point Body weight and body weight gain decreased (P < 0.05)? The CP 40 mg/kg administration group decreased on the 28th, 42nd and 56th days after administration, and the ENU 10 mg/kg administration group on the 42nd and 56th days after administration. The incidence of RBC CD59- in peripheral blood increased on the 7th, 14th, 21st, 28th, 42nd and 56th days after administration in the 40 mg/kg group (P < 0.05), and there was a dose-response relationship.

  Conclusion: In the Pig-a gene mutation test, ENU is better than CP in increasing the incidence of RBC CD59- in peripheral blood of rats, and the dose of 40 mg/kg is better than 10 mg/kg, and the test period is 28 d.