The purpose of this study was to establish an experimental setting and an
anesthetic method compatible with future sequential studies using (18)F-FDG-PET single scans, i.e. autoradiographic measurements, for the estimation of metabolic rate of
glucose (MRglc) in mice. In this study we had no access to a small animal PET scanner and therefore focus was on the
anesthetic setting and optimization of the input function as a preparation for the future
tumor metabolic studies. Initially, four combinations of intraperitoneal (ip)
anesthesia were tested on
tumor bearing mice.
Fentanyl-
fluanisone plus
diazepam yielded low and stable
blood glucose levels and kept the animals sedated for approximately 2 h. The
anesthesia was also tested in a longitudinal (18)F-FDG study, where
tumor bearing mice were anesthetized, injected with (18)F-FDG, and sampled for blood, before, one day after, and 8 days
after treatment with
cisplatin. The animals were in good condition during the entire study period. To validate the method, average MRglc of whole brain and cerebellum in mice were calculated and compared with the literature. The average MRglc in the whole brain and cerebellum were 46.2±4.4 and 39.0±3.1 µmol 100g(-1) min(-1). In the present study, we have shown that an ip
anesthesia with a combination of
fentanyl-
fluanisone and
diazepam is feasible and provides stable and low
blood glucose levels after a fasting period of 4 h in experiments in nude mice with xenografted human
tumors. We have also verified that (18)F-FDG, intraperitoneally administrated, results in an expected plasma activity uptake and clearance. The method doesn't alter the uptake in brain which is an indirect indication that the
anesthesia doesn't alter the uptake in other organs. In combination with meticulous animal handling this set-up is reliable and future sequential
tumor studies of early metabolic effects with calculation of MRglc following cytotoxic
therapy are made possible.