Tissue Distribution of Gadolinium in Rats

Animals were anaesthetised with SevoFlo at an induction rate of 3 to 4% and subsequently by intramuscular injection of 0.20 mL/kg of Zoletil 50/50 (20 mg/kg) and 0.25 mL/kg of Rompun (5 mg/kg). Anaesthetic doses were calculated based on the last recorded body weight. Animals were euthanised and bled after collection of blood from the abdominal aorta. Blood was collected in tubes containing lithium heparin gel and stored at 2 to 8 °C until sample preparation was required for clinical chemistry or inductively coupled plasma/mass spectrometry (ICP-MS) analyses. After exsanguination, a complete macroscopic postmortem examination was performed. Any abnormal findings were recorded. Thereafter, each animal was dissected to obtain the following tissues for ICP-MS determination of Gd: cerebrum, cerebellum, liver, kidneys, peripheral nerves (lumbosacral plexus, sciatic, and tibial nerves from both legs), femur, and skin. Tissues were sampled from all animals using sterile disposable surgical instruments to avoid cross-contamination, weighed, then placed in disposable tubes and frozen at -80 °C ± 10 °C. A total of 461 blood/tissue samples were collected (58 animals; 7 tissue samples [− 3 missing skin samples], and 1 blood sample per animal).