[IL-10 suppresses inflammatory granuloma uptake of 18F-FDG in rats]

To evaluate the effectiveness of IL-10 in suppressing 18F-FDG uptake in the inflammatory granuloma of SD rats.

Eight SD rats were killed, and their blood was collected sterily. After centrifugion, the white blood cells were incubated in PRMI 1640 for 3 days. Then each culture flask of white blood cells was divided into two equal parts. To one group was added 0.2 mL IL-10 solution (0.1 mg/mL); to the control was added with 0.2 mL of 0.9% sodium chloride solution. All cells were then incubated for 120 minutes at 37 degree, after which 18F-FDG (1.85 MBq) was added. Sixty minutes later, the cells were washed twice with PBS and the extent of uptake 18F-FDG determined. In vivo, an inflammatory granuloma was produced by hypodermic injection of rats with a mixture of Freund's complete adjuvant, bovine serum albumin and talcum powder. Each rat was maintained for 8 weeks. Imaging of the inflammatory granulomas was performed using the 18F-FDG signal. IL-10 was injected into SD rats at 10 μg/kg of body weight. Sixty minutes later, 7.4 MBq of 18F-FDG were injected, and, after a further 60 minutes, the rats underwent a PET-CT scan. The region of interest (ROI) of the inflammatory granuloma was delineated and the standard uptake value (SUV) calculated. A second PET-CT scan was done without IL-10 on the next day. The granulomatous tissue underwent pathological examination.

In the intro test, the with blood cell uptaking ratio of 18F-FDG was (50.3±6.7)% without IL-10, and (34.6±3.5)% with IL-10(t=8.9, P<0.01). IL-10 suppressed the rat white blood cell uptaking 18F-FDG. In the PET-CT scan, the SUV of ROI on inflammatory granuloma was 1.7±0.4 with IL-10 and 2.1±0.3 without IL-10 (t=20.6, P<0.01). IL-10 suppressed the inflammatory granuloma uptaking 18F-FDG.

IL-10 can suppress the inflammatory granuloma of SD rats uptaking 18F-FDG.