Investigation of a novel brachytherapy ureteral stent: trial studies on normal beagle dogs.

PURPOSE To evaluate the safety and feasibility of a newly designed 125I brachytherapy ureteral stent (BUS) in normal dogs. METHODS A BUS loaded with 10 125I seeds (Group A: 0.8 mCi, Group B: 0.4 mCi, Group C: 0 mCi) was designed and tested in 27 normal beagle dogs. Routine blood tests, gross observations, cumulative radiation doses, tissue reaction assessed by hematoxylin-eosin/Masson staining, mRNA analysis by RT-qPCR and protein expression of Caspase-3, Collagen I, PCNA, and α-SMA were performed at 2, 4 and 8 weeks. RESULTS The BUS was implanted successfully in all dogs (27/27) without surgery-related death. The ureter diameter and radiation injury score increased along with radiation accumulation (p < 0.05). Histopathologic analysis showed necrotic tissue and lateral fibrosis to different extents in the ureteral walls that gradually increased in all groups (p < 0.05); however, epithelial cell proliferation in groups A and B was lighter than that in the control group (p < 0.05). CONCLUSION Placement of the newly designed 125I BUS was safe and feasible in dogs, and clinical studies are required to test its use in humans.