[Effects of cytochrome P450 isozymes on aristolochic acid renal cytotoxicity].
OBJECTIVE
To investigate the effect of cytochrome P450 isozymes on aristolochic acid induced cytotoxicity on renal proximal tubular epithelial cell (cell line HK-2).


METHODS
Human renal tubular cells (cell line HK-2), were treated with aristolochic acid (AA) alone or in combination with cytochrome P450 isozymes inhibitors, including alpha-naphthoflavone (CYP450 1A1 and 1 A2 inhibitors), ketoconazole (CYP450 3A4 inhibitor), sodium diethyldithiocarbamate (CYP450 2A6 and 2E1 inhibitors), quinidine (CYP450 2D inhibitor), alpha-lipoic acid (NADPH: P450 reductase inhibitor), sulfaphenazole (CYP450 2C inhibitor) in the presence or absence of liver microsome(S9). The inhibition of cell proliferation rate was studied by MTT assay and the lactate dehydrogenase release rate was determined with continuous monitoring method.


RESULTS
AA inhibits cell proliferation and promotes the release of LDH over the range of 12.5-100 mg x L(-1), in a dose-dependent manner. Addition of S9 into the culture system reduced AA cytotoxicity, with the cell proliferation inhibition reducing and the release of LDH decreasing (AA + S9 group vs the same concentration of AA alone group, P < 0.05). In the absence of S9, ketoconazole or alpha-naphthoflavone has no obvious effect on AA cytotoxicity, however,under the conditions of adding S9, ketoconazole or alpha-naphthoflavone enhances AA cytotoxicity. Other inhibitors of CYP450 isozymes has no distinct effect on AA cytotoxicity.


CONCLUSIONS
The microsomal enzyme of Liver can reduce the AA cytotoxicity, and CYP450 3A, CYP450 1A may be the major cytochrome P450 isozymes which impact AA cytotoxicity.
Tang
Xi-lan
XL
Institute of Chinese Materia Medica, Academy of Chinese Medical Sciences, Beijing 100700, China.
Liang
Ai-hua
AH
Yu
Chang-an
CA
Liu
Ting
T
Zhao
Yong
Y
Cao
Chun-yu
CY
Li
Chun-ying
CY
Yi
Yan
Y
Hao
Ran
R
D000818:Animals; D034341:Aristolochic Acids / Q000633:toxicity*; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D003602:Cytotoxicity, Immunologic / Q000187:drug effects*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006801:Humans; D007684:Kidney Tubules / Q000187:drug effects / Q000201:enzymology / Q000276:immunology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar
D034341:Aristolochic Acids; D065607:Cytochrome P-450 Enzyme Inhibitors; D004791:Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System; C000228:aristolochic acid I