Objective To investigate the influence of heme oxygenase-1 (HO-1) on rat renal tubular epithelial cell apoptosis induced by albumin and the possible mechanism. Methods The renal tubular epithelial cells (NRK-52E) were cultured in DMEM/F12 1:1 medium as normal control group; NRK-52E cells were cultured with 30 g/L fat-free bovine serum albumin (BSA) as the BSA control group; NRK-52E cells were cultured with CoPP (Cobalt pretoporphyrin Ⅸ) 5 μ mol/L for 24 hours as the treatment group. MTT assay was used to observe the effects of CoPP on growth inhibition induced by BSA in NRK-52E cells. The effect of CoPP was observed in BSAinduced apoptosis with the fluorescence microscope dyed by AnnexinV-FITC PI. The levels of HO-1, and expression of Bcl-2 and Bax mRNA were detected by reverse transcript polymerase chain reaction (RT-PCR). Results Compared with normal control group, BSA inhibited the growth of NRK-52E cells (P<0.05) and increased cell apoptosis rate (P<0.05). The CoPP pretreatment partially inhibited the BSA-induced apoptosis(P<0.05). Compared with normal control group, HO-1 mRNA expression increased (0.44±0.06 vs 0.39±0.05, P<0.05) in BSA control group. Compared with the BSA control group, the expression of HO-1 mRNA significantly increased after CoPP pretreatment(0.50±0.06 vs 0.44±0.06, P<0.05 ). Meanwhile, BSA increased the expression of Bax mRNA (0.87±0.04 vs 0.67±0.03, P<0.05)and reduced the expression of Bcl-2 mRNA (0.25± 0.04 vs 0.42±0.02, P<0.05 ). CoPP could inhibit the effect of BSA (Bax mRNA: 0.75±0.07, Bcl-2 mRNA: 0.36±0.03, P<0.05, respectively). Conclusions BSA can increase the apoptosis rate significantly and regulate the expression of apoptosis associated proteins in mRNA level directly. CoPP inhibits these changes, which provides evidence to support the essential role of HO-1 in cytoprotective function .