To further analyze the mechanism of UTI on reducing liver cell apoptosis, caspase-3, a cysteine protease critical for executing apoptosis, Bax, a factor to promote apoptosis, and Bcl-2, a family of proteins demonstrated to reduce apoptosis, were measured in liver tissue at 1, 6, and 18 hours after transplantation, respectively. Here, CTSB is linked to bacterial urinary tract infection.