Background and aim: Researchers find that monitoring the differentiation of implanted cells in vivo is difficult. This study was designed to show that it is possible to track the efficacy of transplanted human retinal pigment epithelial cells (RPE cells) in a rat model of Parkinson's disease by using positron emission tomography (PET).
Methods: RPE cells or normal saline were injected into striatum of the injured side of the rat model in treated and control groups, respectively. PET imaging of both groups was undertaken before transplantation and at intervals afterwards, using C-raclopride and C-beta-CFT as the markers. Observation of the rats' behaviour and immunofluorescence confocal microscopy were also used to prove the PET results.
Results: PET studies showed increased accumulation of C-raclopride and decreased C-beta-CFT in the injured side of striatum in both groups. C-raclopride decreased along with a concomitant increase of C-beta-CFT after transplantation in the treated group. The changes shown by the PET studies paralleled the behavioural states and confocal microscopy observations in the treated animals.
Conclusion: These results suggest that even a clinical PET scanner could, to a certain extent, provide some information on the existence and in-vivo differentiation of RPE cells in a rat model of Parkinson's disease.