Longitudinal observation of [C-11]4DST uptake in turpentine-induced inflammatory tissue

作者：Toyohara Jun^*; Sakata Muneyuki; Oda Keiichi; Ishii Kenji; Ishiwata Kiichi

来源：Nuclear Medicine and Biology, 2013, 40(2): 240-244.

DOI：10.1016/j.nucmedbio.2012.10.008

• 4DST
• Inflammation
• Cell proliferation
• Ki-67
• Positron emission tomography

Introduction: Longitudinal changes of 4'-[methyl-C-11]thiothymidine ([C-11]DST) uptake were evaluated in turpentine-induced inflammation.
Methods: Turpentine (0.1 ml) was injected intramuscularly into the right hind leg of male Wistar rats. Longitudinal [C-11]4DST uptake was evaluated by the tissue dissection method at 1, 2, 4, 7, and 14 days after turpentine injection (n=5). The tumor selectivity index was calculated using the previously published biodistribution data in C6 glioma-bearing rats. Dynamic PET scan was performed on day 4 when maximum [C-11]4DST uptake was observed during the longitudinal study. Histopathological analysis and Ki-67 immunostaining were also performed.
Results: The uptake of [C-11]4DST in inflammatory tissue was significantly increased on days 2-4 after turpentine injection, and then decreased. On day 14, tracer uptake returned to the day 1 level. The maximum SUV of inflamed muscle was 0.6 and was 3 times higher than that of the contralateral healthy muscle on days 2-4 after turpentine injection. However, tumor selectivity index remains very high (>10) because of the low inflammation uptake. A dynamic PET scan showed that the radioactivity in inflammatory tissues peaked at 5 mm after [C-11]4DST injection, and then washed out until 20 min. At intervals >20 min, radioactivity levels were constant and double that of healthy muscle. The changes in Ki-67 index were paralleled with those of [C-11]4DST uptake, indicating cell proliferation-dependent uptake of [C-11]4DST in inflammatory tissues.
Conclusion: In our animal model, low but significant levels of [C-11]4DST uptake were observed in subacute inflammation.

• 出版日期2013-2