Resumen
The present study investigated the effects of forced swimming on the technetium-99m (99mTc) labeling of blood constituents (BloCs). Rats (Wistar) were submitted to forced swim. In previous experiments, swimming animals would recover for different periods of time. Animals not submitted to swimming were used as control. Blood samples were obtained and the 99mTc labeling of BloCs was carried out. Blood cells (BCs), plasma (P), insoluble fractions (IF-P and IF-BCs), and soluble fractions (SF-P and SF-BC) were isolated. Radioactivity was determined, and the percentage of 99mTc incorporated (%ATI) was calculated in each fraction. Results showed that forced swimming decreased the percentage of 99mTc incorporated (%ATI) in IF-P (p < 0.05). It is suggested that the 99mTc labeling of BloCs could be used to verify the effects of the stress conditions on BloCs and that the radionuclide fixation on plasma proteins might be altered in rats submitted to acute stress induced by forced swimming, returning to control levels after recovery.