Research Article: Preparation and biodistribution study of ۶۷Ga-rosemary (Salvia rosmarinus Spenn.) extract nanoparticles and its SPECT imaging in healthy rainbow trout (Oncorhynchus mykiss)

The aim of this study was to evaluate the labeling of rosemary extract nanoparticles (RE-NPs) using ۶۷Ga radioisotope, and their biodistribution in healthy rainbow trout (Oncorhynchus mykiss) tissues. RE-NPs were prepared by gamma irradiation (irradiated at a dose of ۳۰ kGy of gamma-ray by ۶۰Co (PX-۳۰ IssIedovapel, Russia, dose rate of ۰.۰۲ Gy sec-۱) and ultra-sonication methods at two concentrations of ۰.۵% and ۱% and labeled by ۶۷Ga radioisotope. Quality control studies were done using the RTLC method. The radiolabeling RE-NPs at ۱% concentration showed ۹۷% efficiency using a mixture of sodium acetate and acetic acid buffer at pH=۶.۵ after ۳۰ min at room temperature. In the biodistribution study, ۵۴ healthy fish were randomly distributed into two treatment groups (n=۱۸ fish/treatment group) and one group served as healthy control. Fish received ۳.۷-۷.۴ MBq (۳۰۰ µL) of radiolabeled RE-NPs at ۱% concentration and free ۶۷GaCl۳, intraperitoneally. The ۶۷Ga-RE-NPs single-photon emission computed tomography (SPECT) demonstrated the highest tracer accumulation in the kidney and the least uptake in the brain at ۲۴ h after injection of ۶۷Ga-RE-NPs. However, ۴۸ h after injection of ۶۷Ga-RE-NPs, the uptake was negligible in all organs as compared to free ۶۷GaCl۳. The obtained results revealed that administration of ۶۷Ga-RE-NPs, as a natural tracer, by IP injection can be a good imaging method to visualize and understand the whole-body, especially the kidney and spleen tissues distribution and pharmacokinetics in healthy rainbow trout.

Keywords:

Rosemary , ۶۷Ga , radiolabeling , Biodistribution studies , Rainbow trout , Gamma irradiation , SPECT