Whole-body glucose uptake in crayfish (Procambarus clarkii): A study of sexual dimorphism via [18F]FDG MicroPET imaging.

Abstract

Crayfish has been used in biomedical research due to their adaptability and resistance. While genetics, molecular biology, behavior assessments, electrophysiology, and microscopy techniques have been employed to study these crustaceans, in vivo metabolic evaluations using imaging techniques remain scarce. From this perspective, the use of micro positron emission tomography (MicroPET) imaging in crustacean models represents a novel approach to understand metabolic processes in these organisms and evaluating potential environmental impacts on aquatic species.

Objective: To assess the regional uptake of [¹⁸F]FDG in male and female crayfish using MicroPET imaging and to find the optimal scan acquisition time.

Methods: Adult male and female crayfish (n = 10/sex, 30-40 g) underwent 1-hour MicroPET scans (6 frames of 10 min) after administration of [¹⁸F]FDG (7.4 ± 1.2 MBq). Standardized uptake values (SUV) were calculated for the brain, gonads, green gland, heart, and ganglia of ventral nerve cord.

Results: The brain, green gland, and subesophageal ganglion exhibited the highest metabolic activity. Significant differences in [¹⁸F]FDG uptake related to sex were observed only in the gonads, with females showing higher uptake than males. No significant differences were found in other structures; nevertheless, male crayfish showed a higher coefficient of variation (44.33-92.7 %) than females (13.11-46.55 %). Exploratory inter-structure correlation analysis showed uniformly high coupling along the ventral nerve cord in both sexes, with males exhibiting stronger coordination between the heart/green gland and abdominal ganglia (Δρ up to ∼0.8), suggesting sex-dependent metabolic integration.

Conclusions: MicroPET imaging is a valuable tool for assessing metabolic activity and sexual dimorphism in crayfish in a single 10-minute scan (40 min after dose administration). These findings provide a groundwork for further studies investigating the physiological and biochemical basis of these differences.