S-Space College of Medicine/School of Medicine (의과대학/대학원) Urology (비뇨기과학전공) Journal Papers (저널논문_비뇨기과학전공)
Apoptosis induced by oxalate in human renal tubular epithelial HK-2 cells
- Issue Date
- Urol Res. 2005 May;33(2):87-92. Epub 2005 Mar 10.
- Caspase 9 ; Caspases/analysis/metabolism ; Cell Proliferation/drug effects ; Epithelial Cells/chemistry/drug effects/metabolism ; Humans ; Kidney Tubules/*cytology ; Oxalates/*toxicity ; Proto-Oncogene Proteins c-bcl-2/analysis/metabolism ; Urothelium/chemistry/drug effects/metabolism ; Apoptosis
- Oxalate is not only considered to be one of the main constituents of urinary stones, but it also has toxic effects on renal tubular epithelial cells, affecting the pathogenesis of nephrolithiasis. We tried to elucidate the effects of oxalate on human renal tubular epithelial cells (HK-2 cells). In addition, we investigated whether the toxic effect of oxalate occurs by apoptosis, and determined the expression of Bcl-2 family and caspase 9 proteins known as apoptosis-related protein. HK-2 cells were incubated with different concentrations of oxalate, and the effect of oxalate on the growth of the cells was assessed by MTT assay. A caspase-3 activity assay and TUNEL assay were performed on HK-2 cells after oxalate exposure in order to evaluate apoptosis. Immunoblot analysis of Bax, Bcl-2, Bcl-xL, and caspase-9 were performed. Oxalate exposure resulted in significant growth inhibition of HK-2 cells as oxalate concentrations increased. The toxic effect of oxalate on HK-2 cells was considered to occur through apoptosis, as suggested by the increase of caspase-3 activity. The percentage of positive nuclei stained using the TUNEL method was 18+/-2.3 in oxalate-treated cells and 2.5+/-0.9 in untreated cells (P<0.05). Bax and caspase-9 protein expression increased significantly as oxalate concentrations increased, but Bcl-2 protein expression decreased. There was no difference in Bcl-xL protein expression among the various concentrations of oxalate. Our results show that oxalate has a toxic effect on HK-2 cells and that this effect is induced by apoptosis, which may be mediated by an intrinsic pathway.
- 0300-5623 (Print)
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