FIGURE 7.

Calorie restriction induced Sirt1 in the renal proximal tubules. A, immunostaining with an anti-Sirt1 antibody shows increased Sirt1 staining in proximal tubules in mice on CR as compared with those in mice on NC. Scale bar, 50 μm. B, immunoblotting showed that Sirt1 protein expression was increased in kidneys of mice under CR for three months. *, p < 0.05 versus mice with NC (n = 4). C and D, effects of calorie restriction on cisplatin-induced acute kidney injury were examined as described under “Experimental Procedures.” In mice on CR diet, the cisplatin-induced acute kidney injury was partially prevented, compared with that in mice on NC. Scale bar, 100 μm. The arrowheads indicate the areas of cisplatin-induced tissue damages. E and F, immunostaining against 4-HNE, a toxic lipid peroxidation product generated by the local H₂O₂, was prominent in mice on NC, but was diminished in mice on CR. Scale bar, 50 μm.