In order to investigate the mechanisms of the renoprotective effects of XP in rats under vasoconstriction condition with CI-AKI, we examined signaling proteins expression levels of three apoptosis markers: caspase-3 and other two bcl family proteins, bcl-2 and bax in cortex regions of kidney (Figures 4A,C,E), as these proteins were well known participating in execution of cellular apoptosis. Here, CASP3 is linked to acute kidney injury.