Different mechanisms of nephrotoxicity caused by amphotericin b and cyclosporin an involving pka and p38 mapk

Amphotericin B (AmB - antifungal) and Cyclosporine A (CsA - immunosuppressant) are commonly used drugs in medical clinics; however, these often present Nephrotoxicity. Thus, the aim of this study was to evaluate if AmB and CsA nephrotoxicity could be associated to oxidative stress and if the PKA and p38 MAPK are involved in cell death, caused by these drugs, in two different segments of the nephron. For this, we used two different cell lines (LLC-PK1 and MDCK) from different segments of the nephron and treated these cells with AmB and CsA. We evaluated the effect of these treatments on cell death on both cells and the involvement of PKA and p38 MAPK pathways in Amphotericin B and Cyclosporin-induced cell death. Further, we investigated the influence of the treatment with the two drugs in oxidative balance, evaluating ROS production, antioxidant enzymes activity (superoxide dismutase and catalase), as well as gene expression of these enzymes. We also analysed the gene expression of gp91phox, p22phox and p47phox. Data were analyzed by one-way analysis of variance (ANOVA), Bonferroni's Multiple Comparison post-Test or Dunn's Multiple Comparison Test to determine the differences among the groups. AmB and CsA caused cell death in both cells lines, however LLC-PK1 presented a higher percentage of cell death caused by AmB and MDCK presented a higher percentage of cell death caused by CsA. ROS production in both cells treated with AmB or CsA have the same profile observed in DNA fragmentation (cell death). The results showed that the treatment with AmB was able to increase the expression of p47phox and gp91phox in both cell lines. The treatment with AmB was able to reduce SOD activity in both cells lines and the treatment with CsA demonstrated that this drug could reduce the activity of SOD and Catalase in LLC-PK1 and MDCK cells. When p38 MAPK and PKA were inhibited in MDCK cells, the percentage of DNA fragmentation decreased, showing that when these cells were treated with AmB or CsA, probably p38 MAPK and PKA were involved in cell death caused by these compounds. This study demonstrated that cells from different regions of the nephron (proximal –LLC-PK1 or distal tubules - MDCK) present different responses to the oxidative stress caused by Amphotericin B (AmB) or Cyclosporine A (CsA), and also showed a differentiated participation of signalling in this process, involving PKA and p38 MAPK pathways.