Intro Stem cells have been evaluated like a potential therapeutic approach for a number of neurological disorders of the central and peripheral nervous system as well as for traumatic mind and spinal cord injury. were made between Hipp-NSCs and NIS-Hipp-NSCs and statistical analysis was performed by using two-tailed College student’s test. Results Our results show the manifestation of the hNIS allows the repeated visualization of NSCs in the brain by using SPECT/CT imaging and does not affect the ability of Hipp-NSCs to generate neuronal and glial cells andin vivohistological analysis of green MTRF1 fluorescent protein (GFP) or β-galactosidase manifestation in the grafted cells. These analyses require the euthanasia of the animals at each time point analyzed and therefore are laborious and time-consuming. Recently the development of noninvasive imaging systems has offered the means to monitor the delivery grafting and survival of stem cells. Current imaging modalities to monitor cells in the brain include magnetic resonance imaging (MRI) single-photon emission tomography (SPECT) positron emission tomography (PET) bioluminescence and fluorescence imaging . The use of fluorescence and luciferase for bioluminescence imaging is an excellent tool to monitor grafted cells in small animals but is not translatable to the human being patient. MRI and SPECT/PET are non-invasive imaging modalities that are suited for human being use. Although MRI has a higher spatial resolution than SPECT/PET the level of sensitivity of detection is definitely higher for SPECT/PET than MRI (SPECT/PET: 10?10-10?12 M levels of probe; MRI: 10?3-10?5 M levels of probe). Additionally PET has the ability to detect reporter genes [10 11 The use of reporter genes to track stem cell fate is particularly appealing as it is TH1338 the only method that allows studying stem cell survival (only viable cells will be able to communicate the reporter TH1338 protein) proliferation (the reporter gene will become passed on to child cells and the related imaging signals will increase in intensity) and death (cells that are apoptotic or deceased will not be able to communicate the reporter protein). Moreover a reporter gene can be placed under cell-specific promoters (e.g. neuron-specific or glia-specific) therefore allowing monitoring of the fate of the transplanted cells within the TH1338 sponsor cells [12 13 When clinicians decide on which reporter gene to use for imaging stem cells important factors to be considered are (1) biological distribution of the gene (2) availability of the probes and (3) TH1338 effect of the manifestation of the reporter gene within the physiology of the cells. In this respect the sodium iodide symporter (NIS) reporter gene represents a good choice for imaging stem cells in the brain because (1) it is not expressed in the brain (2) the radio probes for NIS are readily available in most nuclear medicine clinics and no radio synthesis is required (3) the rate of metabolism and clearance in the body of both radiodiodide and technetium-99m (99mTc) are well known and (4) the imaging potentials of NIS have been demonstrated and [14 15 The use of the NIS to monitor the delivery grafting and phenotypical differentiation of cells after transplantation has recently been investigated in particular in cardiovascular study [16-18]. The NIS has also been used to monitor trafficking of immune cells reported how transfecting immortalized macrophage cell lines with the hNIS allowed monitoring of their migration toward areas of swelling in nude mice by using PET imaging . Up until now however no studies have been reported on the use of the NIS for imaging NSCs in the brain development of rat hippocampal neural stem cells Cell tradition reagents were from Invitrogen (Carlsbad CA USA) except where mentioned. Adult male Sprague-Dawley rats (200-250 g) were anesthetized with isofluorane (4 % by inhalation) and euthanized by decapitation. The brain was rapidly eliminated and the hippocampi were recognized and dissected out. The hippocampi from three or four rats were collected into a 50-ml Falcon tube comprising sterile Dulbecco’s revised Eagle’s medium/F12 (DMEM/F12) medium with antibiotics (penicillin and streptomycin) and kept on TH1338 ice. The cells was minced into.