Fig 1.
213Bi-BSA biodistribution in nude mice.
Biodistribution of 213Bi-BSA was determined at 15, 45, 90 and 180 minutes after injection. Three mice were sacrificed at each time point. The results are expressed as the percentage of injected activity per gram ± SD.
Table 1.
Mean dose to organs with 213Bi-BSA and comparison with mean dose to organs calculated applying 213Bi decay to 125I-BSA biodistribution.
Table 2.
Organ to blood activity ratio with 125I-BSA and 213Bi-BSA at different times.
Fig 2.
Total body weight and survival of mice injected with increasing activities of 213Bi-BSA.
Three groups of mice were injected with 213Bi-BSA at increasing activities: 3.7 MBq (n = 5), 7.4 MBq (n = 7), and 11.1 MBq (n = 5) while a control group (n = 5) was injected with PBS. (A) In the 11.1 MBq injected group, the median survival period was 189 days. In the 7.4 MBq injected group, it was 324 days. In the 3.7 MBq injected group, one mouse died at day 165 and a second one at day 255. The median survival time was not reached in this group. All mice in the control group survived to the end of the assay. *: significant differences. (B) Total body weights were monitored over a 385-day period on the same animals. *: significant differences.
Fig 3.
Haematological toxicity in mice injected with increasing activities of 213Bi-BSA.
Blood counts of WBC (A), RBC (B), and platelets (C) were performed in mice injected with PBS, 3.7 MBq, 7.4 MBq and 11.1 MBq of 213Bi-BSA. The mean numbers (± SD) at each time point are shown.
Fig 4.
Monitoring of plasmatic ALT and AST for liver toxicity assessment.
(A) ALT and (B) AST activity were assessed monthly in plasma of mice injected with PBS (control), 3.7 MBq, 7.4 MBq and 11.1 MBq of 213Bi-BSA. The mean level of ALT and AST (± SD) was expressed relative to the ALT and AST plasma activities at day 0 taken as a reference.
Fig 5.
Plasmatic creatinine and blood urea nitrogen (BUN) monitoring for kidney toxicity assessment.
(A) Creatinine and (B) BUN were assessed monthly in plasma of mice injected with PBS (control), 3.7 MBq, 7.4 MBq and 11.1 MBq of 213Bi-BSA. The mean level of creatinine and BUN (± SD) was expressed relative to the creatinine and BUN plasma levels at day 0 taken as a reference.
Fig 6.
Grade of activity-related hepatic histological features.
Activity-related increases in (A) cytomegaly/karyomegaly, (B) intranuclear cytoplasmic inclusion, and (C) inflammation/fibrosis of control mice (n = 10), mice injected with 3.7 MBq (n = 5), 7.4MBq (n = 8) and 11.1 MBq (n = 6). Histological features were graded on histological slides as follows: 0 (absent), 1 (moderate), 2 (marked) and 3 (severe). Histological grade occurrences in the different groups were compared using Fisher’s exact test. P values ≤0.05 were considered significant.
Fig 7.
Liver histology of control and 213Bi-BSA injected mice.
(A) Control liver, 26 weeks post-injection, (B) livers of mice 26 weeks after injection of 3.7 MBq 213Bi-BSA, and (C, D, E, F) livers of mice 26 weeks after injection of 11.1 MBq 213Bi-BSA. Livers of mice injected with 3.7 MBq 213Bi-BSA do not show any significant histological injury. Livers of mice injected with 11.1 MBq 213Bi-BSA show extramedullary haematopoiesis (C, arrow), isolated necrosis (D, arrow), karyomegaly (Ka), cytomegaly (Cy) and intranuclear acidophilic cytoplasmic invagination (INCI) (E). Inflammation and fibrosis are rarely observed (F, arrow). Haematoxylin-Eosin-Saffron (bar = 100 μm).
Fig 8.
Grade of activity-related renal histological features.
Activity-related increases in (A) cytomegaly/karyomegaly, (B) proteinaceous casts and (C) glomerulosclerosis, of control mice (n = 8), mice injected with 3.7 MBq (n = 5), 7.4 MBq (n = 8) and 11.1 MBq (n = 6). Histological features were graded as follows: 0 (absent), 1 (moderate), 2 (marked) and 3 (severe). Histological grade occurrences in the different groups were compared using Fisher’s exact test. P values ≤0.05 were considered significant.
Fig 9.
Kidney histology of control and 213Bi-BSA injected mice.
Comparison between kidneys of (A, D, G) control animals, (B, E, H) kidneys of mice 35 weeks after injection of 3.7 MBq of 213Bi-BSA, (C and I) 26 weeks after injection of 11.1 MBq of 213Bi-BSA and (F) 35 weeks after injection of 7.4 MBq of 213Bi-BSA. Control kidneys, Haematoxylin-Eosin-Saffron (A), Periodic Acid Schiff (D), and Masson’s Trichrome (G). Kidneys of mice injected with 3.7 MBq 213Bi-BSA do not show any significant histological injury (B (HES), E (PAS) and H (MT)). Kidneys of mice injected with 11.1 or 7.4 MBq 213Bi-BSA show basophilic tubules, karyomegaly and cytomegaly (C, arrow) (HES), proteinaceous casts (F, arrow), (PAS), and glomerulosclerosis (I, arrow) (MT) (bar = 100 μm).