ObjectiveTo investigate the effects and molecular mechanism of endoplasmic reticalam stress (ERS) on albumin-induced apoptosis in renal proximal tubular cells (HKCs). MethodsWestern blot was performed to detect the relationship of the expression of glucose-regulated protein 78 (GRF78) and CCAAT/enhancer-binding protein-homologous protein (CHOP) with the action time and concentration of haman serum albumin (HSA). Expression levels of CHPO mRNA and protein in HKCs after CHOP siRNA transfection were examined by real-time fluorescence quantitative PCR and Western blot respectively. Annexin-V-FITC and PI doable staining cytometry was used to detect the apoptosis of HKCs induced by HSA and influenced by CHOP siRNA. Results(1)After HKCs were stimulatde by 0, 5, 10, 20 g/L albumin for 24 hours respectively, the expression of GRP78, CHOP and HKCs apoptosis were increased with the albumin concentration (P<0.01). After HKCs were stimulated by 20 g/L albumin for 0, 6, 12, 24, 36 hours respectively, the expression of GRP78 was up-regulated at 6-hour, while CHOP and HKCs apoptosis were increased at 12-hour, and significant differences were found among groups (P<0.01). (2) CHOP siRNA significantly inhibited albumin-induced HKC CHOP mRNA and protein expression, as well as HKC apoptosis (P<0.01). ConclusionsRenal tubular cells exposed to high protein load result in EBS. ERS may subsequently lead to tubular damage by activation of pro-apoptosis factor CHOP.