Objective: To employ (18)F-fluoro-2-deoxyglucose ((18)F-FDG) and (3-N-[(11)C] methylspiperone)(11)C-NMSP microPET to assess the changes of regional cerebral glucose metabolism and the expression of dopamine receptor type 2 (DRD(2)) in a rat model of Parkinson's disease (PD).
Methods: A hemiparkinsonian model was established in rats by unilateral pretreatment with 6-hydroxydopamine (6-OHDA). At 2 weeks after 6-OHDA insult, (18)F-FDG and (11)C-NMSP microPET scan were performed to compare the differences of regional cerebral glucose metabolism and the expression of DRD(2) between the PD and control groups respectively. The immunohistochemical staining was used to detect the expression of tyrosine hydroxylase in two groups.
Results: In the PD model, the glucose metabolism rates were 88.2% ± 2.2%, 94.5% ± 4.5% and 96.2% ± 5.8% respectively, in right striatum, hippocampus and sensorimotor cortex. And they were significantly lower than those in the control group [92.7% ± 2.8% (P < 0.01), 98.9% ± 3.9% (P < 0.01) & 102.8% ± 2.1% (P < 0.01)]. The expression of DRD(2) in right striatum was significantly higher in the PD group than that in the control group (112.9% ± 9.0% vs 102.3% ± 1.4%, P < 0.01).
Conclusion: In the PD rats, glucose metabolism decreases in injured side striatum, hippocampus and sensorimotor cortex while and the expression of DRD(2) increases in injured side striatum.(18)F-FDG and (11)C-NMSP microPET can effectively assess the regional cerebral glucose metabolism and the expression of DRD(2) in PD. They may serve as effective molecular imaging tools for an early diagnosis of PD.