Fig. 2.
The level of the p16INK4a protein immunostaining in mouse islet cells depends on glucose and mTOR activation. The p16INK4a protein was detected in the cytosol (a, d), nucleus (b, e), and whole cell (c, f) in pancreatic mouse islets cells exposed to glucotoxicity in the presence or absence of 1 nM rapamycin for 72 h (a−c) or 7 days (d−f). The p16INK4a immunostaining displays a glucose-dependent trend to increase in cytosol and nucleus that is more prominent and even significant for the whole cell level after a 7 days-exposure to glucotoxicity. Rapamycin reduces p16INK4a immunostaining irrespective of time and glucose concentration. Representative images of the p16INK4a cellular localization and immunofluorescence in islet cells exposed to glucotoxicity in the presence or absence of rapamycin for 7 days (g, border of the cells highlighted in yellow in the upper traces). a−c: Circles indicate cells evaluated from three independent female mouse preparations; d−f: the circles and squares represent individual cells analyzed from three independent mouse preparations, two females and one male, respectively (~ 8-months of age). *p < 0.05; **p < 0.01; ***p < 0.001. Scale bar (g) = 10 µm