OBJECTIVETo establish a stable recipient mouse model for stem cell transplantation into seminiferous tubules and improve the traditional techniques for transplantation.

METHODSSixty male ICR mice were equally divided into Groups A, B, C and D, and injected with Busulfan at 15 mg/kg, 30 mg/kg, 40 mg/kg and 0 mg/kg, respectively. The survival rate was recorded every day, and the testis weight and spermatogenesis of testicular tubules were determined at 4, 8 and 12 weeks after the injection. We improved the stem cell transplantation technique and designed a new transplantation device, which connected the nozzle end, syringe and puncture needle by a three-way joint. The nozzle end was used for tentative injection, and the syringe for drawing and then injecting the cell suspension.

RESULTSOnly one mouse in Group C died after the injection. At 4 weeks after Busulfan treatment, the testis weight decreased apparently in Groups A, B and C, with significant differences from D (P < 0.05). The differences remained significant at 8 weeks (P < 0.05), except between Groups A and D (P > 0.05), but at 12 weeks none of the first three groups showed any significant difference from Group D (P > 0.05). At 4 and 8 weeks, the rate of hollow seminiferous tubules was < 50% in Group A and > 50% in Groups B and C, and almost returned to normal at 12 weeks, with no significant differences among the three groups (P > 0.05), but it remained unchanged in Group D. The improved transplantation device increased the success rate (> 90%), lowered the donor cell loss (< 50 microl cell suspension needed for both testes) and shortened the process ( < 10 min for one testis).

CONCLUSIONIntraperitoneal injection of Busulfan at 30 mg/kg is suitable for the establishment of the recipient mouse model of stem cell transplantation. The improved transplantation device and methods help promote the efficiency and success rate of the transplantation operation.