An anesthetic method compatible with (18)F-FDG-PET studies in mice.

Area of Science:

• Preclinical research
• Medical imaging
• Anesthesiology

Background:

• Accurate estimation of glucose metabolism is crucial for understanding tumor progression and treatment response.
• Sequential studies require reliable anesthetic protocols that do not interfere with metabolic measurements.
• Small animal Positron Emission Tomography (PET) imaging with Fluorodeoxyglucose (FDG) is a key tool for metabolic rate of glucose (MRglc) assessment.

Purpose of the Study:

• To establish and validate an experimental setting and anesthesia method for future sequential (18)F-FDG-PET studies in mice.
• To optimize the anesthetic protocol for accurate MRglc estimation in tumor-bearing mice.
• To prepare for longitudinal studies assessing early metabolic effects of therapies.

Main Methods:

• Four intraperitoneal (ip) anesthesia combinations were tested in tumor-bearing mice.
• Fentanyl-fluanisone plus diazepam was selected for its ability to maintain low, stable blood glucose and sedation for ~2 hours.
• The chosen anesthesia was tested in a longitudinal (18)F-FDG study, including blood sampling before and after cisplatin treatment.

Main Results:

• Fentanyl-fluanisone plus diazepam ip anesthesia provided stable, low blood glucose levels after a 4-hour fast in mice with xenografted tumors.
• Intraperitoneal (18)F-FDG administration showed expected plasma activity uptake and clearance.
• MRglc values for whole brain and cerebellum were comparable to literature values, indicating the anesthesia did not significantly alter brain uptake.

Conclusions:

• Intraperitoneal anesthesia with fentanyl-fluanisone and diazepam is a feasible and reliable method for mice in metabolic studies.
• This anesthetic approach supports future sequential (18)F-FDG-PET studies for MRglc estimation in tumors.
• The validated method facilitates research on early metabolic changes following cytotoxic therapy.