Validation of an in vivo imaging model in mice to study the Collagen-induced Arthritis using near infrared fluorophore-labeled 2-deoxyglucose

SALINAS, FACUNDO JOSÉ; JUAN M PÉREZ SÁEZ ; PABLO F. HOCKL ; , NATALIA R. SALVETTI; HUGO H. ORTEGA

Mar del Plata

Congreso; Reunión Conjunta de la Sociedad Argentina de Investigación Clínica (SAIC), la Sociedad Argentina de Inmunología (SAI) y la Sociedad Argentina de Fisiología (SAFIS); 2018

Sociedad Argentina de Investigación Clínica (SAIC), la Sociedad Argentina de Inmunología (SAI) y la Sociedad Argentina de Fisiología (SAFIS)

In vivo bioluminescent imaging systems are increasingly being utilized as a reference method in biomedicine due to its advantages of high sensitivity, non-invasiveness, no radioactivity, and low cost. The effectiveness of optical imaging heavily depends on the properties of the optical imaging probes and the use of validated models. Rheumatoid arthritis (RA) is a systemic autoimmune disease that mainly affects the joint synovium, leading to chronic inflammation, joint destruction, and finally loss of function. Pathogenesis of the disease involves a complex interaction between the innate and adaptive arms of the immune system, in concert with resident fibroblast-like synoviocytes, sustaining this inflammatory microenvironment. The collagen-induced arthritis (CIA) mouse model is induced by immunization with type II collagen (CII) and it is the most commonly studied autoimmune model of rheumatoid arthritis. Previous works from our laboratory has demonstrated that glucose metabolism is increased in stromal cells and infiltrating cells in this arthritis model. Taking into account these observations, our aim was to evaluate the biodistribution of 2-deoxyglucose (2-DG) labeled with a NIR fluorophore for in vivo optical imaging in mice. 2-DG is a glucose analog that utilizes the GLUT transporters and upon phosphorylation, it is not metabolized further and is effectively trapped within the cell. Male DBA/1 mice (8?12 wk old) (n=3) were immunized with 100 mg of CII emulsified in CFA by intradermal injection at the base of the tail. At day 40 when the symptoms were manifested, 20nmol of IRDye 800CW labeled 2-DG were administrated EV. Non-immunized mice were used as control. The images were acquired at 0, 4, 6, 12 and 24 h after administration with a Pearl Trilogy Image System (LI-COR Biosciences) with Ex/Em setting at 785/820 nm. A specific distribution of 2-DG was observed in arthritic mice joints compared to nonarthritic control mice. The fluorescence was evidenced specifically in distal limb joints and mandibular area, with a significant difference in the fluorescence signal (p< 0.05) from 4 hours (3.79+/-1.48), up to 24 hours (3.55+/-0.91) in relation to basal signaling (0.09+/-0.07). These data indicate that targeting metabolic pathways is a novel approach to analyze experimental models of arthritis.