Figure 6.

Megalin ablation in Ctns^−/− kidneys protects against apoptosis and prevents increased PTC turnover. (A) Triple fluorescence confocal imaging for L. tetragonolobus lectin (LT-lectin) signal as proximal tubule marker (represented in white), caspase-3a (cleaved, active caspase-3) as apoptotic marker (green), and Ki-67 as proliferation marker (red) in representative low-power views. Notice increased labeling for both markers in Ctns^−/− but not double KO kidneys. (B) PTC turnover quantification. Cells labeled for caspase-3a or Ki-67 were counted in kidney sections at 6 months (four mice in Ctns^+/−, Ctns^−/−, and Ctns^−/−/Meg^ksKO; two mice for Meg^ksKO; ten random cortical fields totaling 2.98 mm² per section). Statistical analysis of the significance of differences of frequencies in tubes (combined with lumina for apoptosis) by Mann–Whitney test, *P<0.05. Increased apoptotic and proliferation indices in Ctns^−/− kidneys indicate accelerated PTC turnover, not observed in double KO. CTL, control.