Lipoxin A4 induces apoptosis of rat renal interstitial fibroblasts via up regulation of Smac expression / 中华肾脏病杂志

ABSTRACT

Objective To examine whether lipoxin A4(LXA4) induces apoptosis of rat renal interstitial fibroblasts and explore the mechanism concerned.Methods Rat renal interstitial fibroblasts (NRK 49F cells)were incubated in RPMI 1640 medium supplemented with 5%fetal calf serum and exposed to LXA4 at the concentration of 10 nmol/L, 100 nmol/L or 1 ?mol/L for 24 hours. Prior to experiment,some NRK 49F cells were transfected with Smac antisense oligodeoxynucleotide. Apoptosis of NRK 49F cells was recognized by double staining using fluorescent dye acridine orange and ethidium bromide,and observed under laser scanning confocal microscopy and counted by flow cytometry following propidium iodide and annexin staining. Activity of caspase 3 was measured by colorimetric assay. The expression of Smac was determined by Western blotting analysis.Results LXA4 at the concentration of 100 nmol/L or 1 ?mol/L induced apoptosis of 9 83%or 33 82%of NRK 49F cells respectively, and reduced the cells of S and G2～M phase and increased the cells of G0～G1 phase in a dose dependent manner. Treatment of NRK 49F cells with LXA4 up regulated the expression of Smac protein and increased the activity of caspase 3. The transfection with Smac antisense oligodeoxynucleotide inhibited the LXA4 induced apoptosis and expression of Smac in NRK 49F cells. Conclusion LXA4 at high concentration can induce apoptosis of rat renal interstitial fibroblasts via the up regulation of Smac expression.