| Co-Investigator(Kenkyū-buntansha) |
TANIGAWARA Yusuke Kyoto Univ., Medicine, Instructor, 医学部, 助手 (30179832)
KAMIYA Akira Kyoto Univ., Medicine, Lecturer, 医学部, 講師 (90124792)
INUI Ken-ichi Kyoto Univ., Medicine, Associate Professor, 医学部, 助教授 (70034030)
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| Research Abstract |
The kidney is a major organ for the excretion of xenobiotics, and is susceptible to drug-induced nephrotoxicity. We attempted to establish new methods for the evaluation and protection of nephrotoxicity of drugs by using a cultured kidney epithelial cell line, LLC-PK_1. Aminoglycoside antibiotics, cyclosporin (immunosuppressive agent), and cisplatin (antitumor agent) were employed in this study. These drugs are widely used clinically, but their use is sometimes complicated by acute nephrotoxicity.
1. The effect of aminoglycoside, cyclosporin, and cisplatin was tested in LLC-PK_1 cells, and it was found that the number of viable cells, the number of floating cells (dead cells), the ability to form domes, and the activities of apical marker enzymes (aminopeptidase, alkaline phosphatase, and gamma-glutamyltransferase) are useful as markers of drug-induced cytotoxicity. There was a good relationship between the potencies of various aminoglycosides to inhibit apical enzymes in LLC-PK, cells
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and the nephrotoxic potencies of these drugs in vivo. In addition, aminoglycoside and cyclosporin induced the elevation of cytosolic free calcium concentration, which may be a important determinant of drug-induced nephrotoxicity.
2. The inhibitory effect of gentamicin on the apical enzyme activities was dosedependent, and was related to its accumulation in the cells. Apparently, intracellular accumulation of cyclosporin was also related to its cytotoxicity, when judged by the level of cytosolic free calcium and the number of viable cells.
3. Cytotoxicity of cisplatin was more potent on exponentially growing cells than on confluent cells. Glutathione attenuated the toxicity of cisplatin. In contrast, cyclosporin was toxic on growing and confluent cells, and glutathione had no effect on its cytotoxicity, indicating that biochemical mechanisms of nephrotoxicity are different among different drugs.
In conclusion, cultured kidney epithelial cell line (LLC-PKi) should be a useful model system to evaluate the nephrotoxicity of drugs, and to develop a new method to protect the drug-induced nephrotoxicity. Less
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