Ischemic vs. nephrotoxic acute renal failure, early time points (2h and 8h)

Acute renal failure (ARF) has high morbidity and mortality. In animal ARF models, effective treatments must be administered before or shortly after the insult, limiting their clinical potential. We used microarrays to identify early biomarkers that distinguish ischemic from nephrotoxic ARF, or that detect both injury types. We compared rat kidney transcriptomes 2 and 8 hours after ischemia/reperfusion and after mercuric chloride. Quality control and statistical analyses were necessary to normalize inter-experimental groups, eliminate outliers, and exclude unaltered genes. Principal component analysis revealed distinct ischemic and nephrotoxic trajectories, and clear array groupings. Therefore, we used supervised analysis, t-tests and fold changes, to compile gene lists for each group, exclusive or non-exclusive, alone or in combination. Keywords: Disease classification/time course We used two lots of microarrays (Lot 1, n = 24, Lot 2, n = 12), for a total of 36 microarrays. Five of them were duplicates, where two aliquots of RNA from the same rat were processed independently and hybridized to separate microarrays. Normal rats were used in both lots (n = 3 for each lot) for normalization.