OBJECTIVE:To examine changes in the morphology and physiological functions of human proximal tubular epithelial cells (HK-2 cells) caused by total Dahuang (Radix Et Rhizoma Rhei Palmati) anthraquinones (TDA) and emodin.METHODS:HK-2 cells were cultured on polycarbonate (PCF) membranes to form a complete monolayer of cells.A fluorescein isothiocyanate-dextran (FITC) permeability assay was conducted and secretion of γ-glutamyltranspeptidase (GGT),lactate dehydrogenase (LDH),N-acetyl-β-D-glucosaminidase (NAG) and kidney injury molecule 1 (KIM-1) was examined.The reabsorption of glucose and the excretion of para-aminohippuric acid (PAH) by HK-2 cells were also examined.The morphology of HK-2 cells was observed using optical microscopy and scanning electron microscopy.The cytoskeleton of HK-2 cells was observed under a fluorescence microscope.RESULTS:Compared with the results for the dimethyl sulfoxide group,treatment of cells with TDA and emodin showed statistically significant differences in the FITC leakage rate,the apical/basolateral ratio of LDH and GGT,and the secretion of GGT,LDH,NAG and KIM-1.At 64 μg/mL,TDA markedly inhibited blood glucose reabsorption and remarkably suppressed PAH excretion by HK-2 cells.Both TDA and emodin caused various degrees of damage to the morphology and cytoskeleton of HK-2 cells with the degree of damage correlating positively with the dosage of the tested substances.CONCLUSION:Both TDA and emodin caused damage to human renal proximal tubular epithelial cells at certain dosages.At the same dosage,TDA caused more severe damage than emodin to the HK-2 cells.