Title:Doxorubicin-Induced In Vivo Nephrotoxicity Involves Oxidative Stress- Mediated Multiple Pro- and Anti-Apoptotic Signaling Pathways
VOLUME: 9 ISSUE: 4
Author(s):Tejas S. Lahoti, Darshan Patel, Venkatesh Thekkemadom, Robert Beckett and Sidhartha D. Ray
Affiliation:Department of Pharmaceutical Sciences Manchester University College of Pharmacy* 10627 Diebold Rd, Fort Wayne, IN 46845, USA.
Keywords:APAF-1, apoptosis, Bad, Bax, Bcl-2, Bcl-xL, Caspase-3, doxorubicin, lipid peroxidation, Mdm2, necrosis,
nephrotoxicity, oxidative stress, p53, SOD
Abstract:Doxorubicin (DOX), a prominent anticancer agent has enjoyed considerable popularity in the last few decades
because of its usefulness in the management of various forms of cancers, but its organotoxic potential (cardio-, hepatoand
nephrotoxicity) has constrained on its clinical use. This study investigated whether DOX has the ability to cause
nephrotoxicity in vivo and if so, whether it is linked to oxidative stress (OS). Another important goal was to describe
whether expression of pro- and anti-apoptotic genes in kidneys was driven by OS. In order to explore DOX’s nephrotoxic
potential, male rats (Sprague Dawley; 500–520g; fed ad libitum) were administered i.p. with a single dose of DOX (12
mg/kg) on day one and sacrificed seven days later (day 8). Changes in serum chemistries (i.e., serum urea nitrogen, SUN,
and creatinine) were determined immediately upon sacrifice, whereas kidney tissues were subjected to several sensitive
biomarkers for OS, such as, lipid peroxidation, Superoxide dismutase (SOD) activity and chromatin fragmentation. The
most important goal was to evaluate the select expression of Apaf-1, Caspase-3, Bad, Bax, Bcl-2, Bcl-xL, p53 and Mdm2
genes in order to understand the underlying link between extrinsic and intrinsic pathways of cell death. Data revealed that
DOX-exposed animals showed significant nephrotoxicity as reflected in increased SUN (5.6-fold) and creatinine (2.65
fold) levels with considerably decreased body weight. Increases in kidney injury markers reflected parallel elevations in
lipid peroxidation (1.7-fold) and genomic DNA fragmentation (2.9 fold) coupled with a proportionate reduction in total
SOD activity suggesting DOX-assaulted kidneys encountered massive OS. Western blot showed very striking changes: i)
substantial increases in the expression of pro-apoptotic APAF-1, Caspase-3, Bax and Bad proteins; ii) Reduction in the
expression of anti-apoptotic Bcl-2 and Bcl-xL genes; iii) considerable increase in the expression of p53 and suppression of
its regulator Mdm2. Serum chemistry and tissue biochemistry mirrored histopathology. In conclusion, this study for the
first time may have shown a close link between mitochondrial perturbations and cell death regulating genes during DOXinduced
nephrotoxicity, and described DOX’s potential to inflict kidney injury in addition to other organs during
chemotherapy in clinical setting.
