Streptozotocin (STZ) and schistosomiasis mansoni change the biodistribution of radiopharmaceutical sodium 99mTc-pertechnetate in mice.

Introduction Technetium-99m ( 99m Tc) is a radionuclide commonly used in nuclear medicine to obtain 99m Tc-radiopharmaceuticals, which can be used to evaluate either physiological processes or changes related to diseases. It is also used in some experimental studies. Streptozotocin (STZ) administration to rodents causes lesions in very early stages and induces severe and permanent diabetes. Most morbidity of schistosomiasis mansoni is attributed to a granulomatous inflammatory response and associated liver fibrosis. This study was designed to investigate whether STZ administration and schistosomiasis modify the biodistribution of the radiopharmaceutical sodium 99m Tc-pertechnetate. Methods Adult female mice were infected by exposure to 100 Schistosoma mansoni cercariae (BH strain, Belo Horizonte, Brazil) and euthanized after nine weeks. STZ was administered by a single intraperitoneal injection of 100 mg/kg body weight, 3 or 15 days before euthanasia. Each animal received 100 μl of sodium (Na) 99m Tc-pertechnetate ( 99m TcO 4 − ) (740 kBq). The animals were divided into four groups: A, uninfected; B, infected; C, uninfected + STZ; and D, infected + STZ. Blood, brain, thyroid, heart, lungs, liver, spleen, pancreas and kidneys were removed. The radioactivity was counted and the percentage of the injected dose of Na 99m TcO 4 per gram of the organ (% ID/g) was determined. Results Three days after the STZ injection, there was a decrease of Na 99m TcO 4 uptake by the liver, lungs, pancreas and kidneys ( p < 0.05) in group D when compared with group A. After 15 days, the decrease of Na 99m TcO 4 uptake occurred also in the brain, thyroid, heart, spleen and blood ( p < 0.05) in group D. Conclusion We demonstrated modifications on the biodistribution of Na 99m TcO 4 due to STZ administration and schistosomiasis, possibly due to physiological alterations in some organs. Advances in Knowledge and Implications for Patient Care The biodistribution of radiopharmaceutical Na 99m TcO 4 should be carefully evaluated in subjects with diabetes and/or schistosomiasis infection. [ABSTRACT FROM AUTHOR]