OBJECTIVETo study whether aristololactam I (AL-I) induces injury in human renal proximal tubular epithelial cells.

METHODCultured human renal proximal tubular epithelial cell line HK-2 was used as the subject. Aristolochic Acid I (AA-I) was used as a positive control. Cell toxicity of AL-I was detected by LDH releasing rate. Cell apoptosis was evaluated by cellular morphology, DNA content and expression of cell membrane phosphatidylserine (PS). The secretion level of fibronectin (FN) and TGF-beta1 in HK-2 cells were assayed by ELISA.

RESULTAL-I had a direct toxicity on HK-2 in a dose dependent manner from 2.5 mg x mL(-1) to 20 mg x mL(-1); In these range of concentration, AL-I could induce cell apoptosis which was detectable by measurements of morphology, DNA content and expression of PS. AL-I could stimulate the secretion of FN and TGF-beta1. The potency of AL-I cell toxicity was higher than AA-I at the same concentration. The effects of AL-I on apoptosis, secretion of FN and TGF-beta1 were all weaker than AA-I.

CONCLUSIONAL-I as one metabolite of AA-I in vivo induces direct injury in renal proximal tubular cells. Its effects are similar to those of AA-I. AL-I may be one of toxic metabolites in Chinese herbs containing AA which participate in renal damage and fibrosis.