Action of indomethacin on the response of inflammatory process experimentally induced. A study using positron emission tomography (PET) and 18F-fluorodeoxyglucose (FDG)

Abstract

The use of 18F-fluordeoxiglicose (FDG) allows malignant processes to become clearly identified on images of positron emission tomography (PET) as areas of increased glycolytic metabolism. Unfortunately, certain benign processes also exhibit high avidity for radioactive glucose and they may cause misinterpretations. Among them, we highlight the inflammatory process, which often generates false-positive results. Thus, it is evident that a drug intervention that reduces the inflammatory component of the PET image is essential to increase the specificity of the test in its oncological use. In our study, 15 mice will be divided into 3 groups: Group Saline, which will act as a negative control; Group Carrageenan, in which carrageenan, a pro-inflammatory substance, will be injected into the footpad of mice; and Group Carrageenan + Indomethacin in which, besides the carrageenan, the anti-inflammatory indomethacin is administered intraperitoneally. By being proportional to inflammation generated, the degree of edema will be acquired indirectly by the analyzes of the variation in paw volume using a hydropletismometer. Images of PET will be taken on the acute and subacute inflammation phases in all groups. Quantification of the amount of FDG on the analyzed paw will be compared with the degree of oedema shown. From this, it is hypothesized that while carrageenan would lead to an increased glucose uptake on the image of PET, indomethacin would reduce the degree of incorporation of the labeled glucose. Therefore, the study would confirm if the use of indomethacin leads to a reduction of the intensity of the marking of an inflammatory process in PET, what could possibly be used to increase the specificity of this method on clinical trials on future patients. (AU)