Related Experiment Video
Updated: Aug 30, 2026
Isolation, Characterization, And High Throughput Extracellular Flux Analysis of Mouse Primary Renal Tubular Epithelial Cells
Published on: June 20, 2018
In vitro FK506 kidney tubular cell toxicity
A Moutabarrik1, M Ishibashi, H Kameoka
1Department of Urology, Osaka University, Osaka, Japan.
Abstract:
Nephrotoxicity is the most prominent side effect of the new immunosuppressive drug FK506. Some of the histopathological changes associated with cyclosporine (CyA) nephrotoxicity such as tubular vacuolization and glomerular thrombosis have also been reported with FK506 therapy. In this study we used kidney tubular cells in culture to address the issue of FK506- and CyA-induced tubular damage. Exposure of tubular cells to high concentrations of FK506 or CyA (10, 50 and 100 microM) induced a time- and dose-dependent cell injury in vitro characterized by a direct cytotoxic effect on tubular cells as expressed by release of 3H-thymidine from prelabelled cells, N-acetyl-beta-D-glucosaminidase (NAG) release and cell detachment. Ultrastructural changes (vacuolization, swelling and mitochondrial enlargement) and inhibition of the growth (DNA and RNA synthesis) of cultured tubular cells were also observed at high concentrations of FK506 and CyA. These concentrations are higher than those reached in clinical situations, but close to the concentrations that may be reached by FK506 or CyA in tissues. Low concentrations of FK506 and CyA (1, 0.1 and 0.01 microM) were not cytotoxic and induced only a minimal inhibitory effect on the growth of tubular cells in vitro. At the same concentration CyA induced more cell detachment, more NAG release and a stronger inhibitory effect on cell growth than FK506 (P < 0.01). Since an evident cytotoxic effect was observed only at high concentrations, we can speculate that tubular toxicity is due to the accumulation of drug in the cells inducing cell disruption and death.
Insights
High concentrations of immunosuppressants FK506 and cyclosporine (CyA) cause kidney tubular cell damage in vitro. Cyclosporine showed greater toxicity than FK506 at equivalent concentrations, suggesting drug accumulation causes cell injury.
Area of Science:
- Nephrology
- Toxicology
- Cell Biology
Background:
- Nephrotoxicity is a significant side effect of immunosuppressive drugs like FK506.
- Histopathological similarities exist between FK506 and cyclosporine (CyA) induced nephrotoxicity, including tubular vacuolization and glomerular thrombosis.
Purpose of the Study:
- To investigate the direct cytotoxic effects of FK506 and CyA on kidney tubular cells in vitro.
- To compare the tubular damage induced by FK506 and CyA at various concentrations.
Main Methods:
- Kidney tubular cells were exposed to different concentrations of FK506 and CyA (0.01–100 microM) in vitro.
- Cell injury was assessed by measuring 3H-thymidine release, N-acetyl-beta-D-glucosaminidase (NAG) release, and cell detachment.
- Ultrastructural changes and inhibition of DNA/RNA synthesis were evaluated.
Main Results:
- High concentrations (10, 50, 100 microM) of FK506 and CyA induced time- and dose-dependent cytotoxic effects and ultrastructural damage in tubular cells.
- Low concentrations (0.01, 0.1, 1 microM) showed minimal cytotoxicity and growth inhibition.
- CyA demonstrated significantly greater cell detachment, NAG release, and growth inhibition than FK506 at equivalent low concentrations (P < 0.01).
Conclusions:
- FK506 and CyA exhibit direct cytotoxic effects on kidney tubular cells, particularly at high concentrations.
- The observed tubular toxicity may result from drug accumulation within cells, leading to disruption and death.
- Cyclosporine appears to be more potent in inducing tubular damage compared to FK506 at similar concentrations.
