Fig 3. Representative immunolabeling for insulin, glucagon, caspase-3, PCNA, Trx1 and Prx2 in pancreatic islets in water (W), regular cola (C) and light cola (L) groups.

Longitudinal Panels A and B: Classical cytoplasmic expression of insulin and glucagon was observed at 6 and 12 months of study. Longitudinal Panels C and D: The area of immunolabeling for insulin was irreversibly reduced after regular cola drinking. In addition, the cytoplasmic expression of glucagon showed a transient decrease at 6 months which recovered at 12 months. Regular cola drinking did not modify the apoptotic and proliferative activities. However, over the study time, the cytoplasmic immunolabeling for PCNA decreased and immunolabeling for Trx1 and Prx2 increased, suggesting a complex phenomenon linked to the redox pathway. Longitudinal Panels E and F: Light cola treatment induced a reversible decrease in insulin immunolabeling at 6 months and did not modify the cytoplasmic expression of glucagon. Scarce effects in apoptotic or proliferative conditions were observed after light cola drinking (the arrow indicates an isolated PCNA positive nucleus within the islet). Interestingly, cytoplasmic expression of PCNA decreased while cytoplasmic immunolabeling for Trx1 and Prx2 increased at the end of the wash-out period. Magnification 40 X. Scale bar: 100 μm. PCNA: Proliferating cell nuclear antigen; Trx1: thioredoxin 1; Prx2: peroxiredoxin 2.