Ethanol (EtOH) exposure potentiates diclofenac (DCLF)-induced nephrotoxicity in vivo

More than 70 million prescriptions for NSAIDs (Non-steroidal anti-inflammatory drugs) are written each year, and over-the-counter use included, more than 30 billion doses of NSAIDs are consumed annually in the US alone. In 2009, Poison Control Centers reported over 337,000 exposures out of which analgesics (NSAIDs PLUS NON-NSAIDS) ranked the highest and recorded an increase of 13,000. Among several NSAIDs, diclofenac (DCLF) is frequently prescribed for pain management and treatment of various conditions like arthritis, rheumatoid arthritis and osteoarthritis. Our previous studies have shown nephrotoxic and apoptogenic potentials of DCLF (Hickey et al., 2001; Bhatt et al., FASEB J, 2008). On the other hand, alcohol-potentiated xenobiotic toxicity remains an extensively investigated area of research and ethanol's (EtOH) ability to potentiate DCLF-induced organ injury remains a new challenge for investigation. This study investigated: i) whether exposure to EtOH can potentiate DCLF-induced nephrotoxicity, and ii) whether the underlying mechanisms of this potentiation are genomic injury, increased apoptosis and an imbalance in pro- and anti-apoptotic gene expression. To explore this interaction, female ICR mice (3 months old) were kept on regular diet and, either plain tap water or EtOH containing drinking water (Week1:3%, Week2:4%, Week3:5%, Week 4:6%). On day-28, a single dose of DCLF (150 mg/kg) was administered orally, and all animals were sacrificed 24 hours later. Blood was collected for serum chemistry and kidneys for tissue biochemistry & pathology. Serum BUN reflected potentiation of nephrotoxicity (mg/dl: Con: 30; EtOH alone: 31; DCLF alone: 68; Et0H+DCLF: 132). Concurrent genomic injury and oxidative stress caused genomic instability and altered pro-apoptotic Bid, BCL-2and PARP-1 expressions in EtOH+DCLF group compared to DCLF alone. Kidney sections mirrored cell death patterns (apoptosis & necrosis) that were consistent with tissue biochemistry in all treatment groups. Overall, this study suggests that EtOH-exposure prior to DCLF administration may exacerbate nephrotoxicity and also DCLF prescription to regular thinkers may require precaution.