Project description:This experiment was designed to study the alteration in expression of mRNA is kidney following recovery from transient acute renal failure. The model used was a 52 min. bilateral renal artery clamping, followed by reperfusion, which resulted in a transient loss of renal function, followed by a functional recovery. All tissue in this study was harvested 35 days post-surgery, when renal function was restored, and renal structure largelyy normal. For controls, sham-operated animals were used. An N of 6 post-ischemia reperfusion animals were used with 6 sham-operated controls. For hybridization studies, RNA from one of six post-ischemic acute renal failure animals were compared with with RNA from kidney of six sham-operated control animals. Each ARF vs. sham-operated comparison was performed twice, alternating the cy3 and cy5 label between the two hybridizations for each pair. A second set of hybridizations was carried out using sham vs. sham hybridizations. This was done to get a quantitative analysis of the variation of the biological and microarry platform.
Project description:This experiment was designed to study the alteration in expression of mRNA is kidney following recovery from transient acute renal failure. The model used was a 52 min. bilateral renal artery clamping, followed by reperfusion, which resulted in a transient loss of renal function, followed by a functional recovery. All tissue in this study was harvested 35 days post-surgery, when renal function was restored, and renal structure largelyy normal. For controls, sham-operated animals were used. An N of 6 post-ischemia reperfusion animals were used with 6 sham-operated controls. For hybridization studies, RNA from one of six post-ischemic acute renal failure animals were compared with with RNA from kidney of six sham-operated control animals. Each ARF vs. sham-operated comparison was performed twice, alternating the cy3 and cy5 label between the two hybridizations for each pair. A second set of hybridizations was carried out using sham vs. sham hybridizations. This was done to get a quantitative analysis of the variation of the biological and microarry platform. Keywords: parallel sample
Project description: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
Project description: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. 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.
Project description:We created a rat renal congestion model and investigated the effect of renal congestion on hemodynamics and molecular mechanisms. The inferior vena cava (IVC) between the renal veins was ligated by suture in male Sprague-Dawley rats to increase upstream IVC pressure and induce congestion in the left kidney only. Left kidney congestion reduced renal blood flow, glomerular filtration rate, and increased renal interstitial hydrostatic pressure. Tubulointerstitial and glomerular injury and medullary thick ascending limb hypoxia were observed only in the congestive kidneys. Molecules related to extracellular matrix expansion, tubular injury, and focal adhesion were upregulated in microarray analysis. Renal decapsulation ameliorated the tubulointerstitial injury. Electron microscopy captured pericyte detachment in the congestive kidneys. Transgelin and platelet-derived growth factor receptors, as indicators of pericyte-myofibroblast transition, were upregulated in the pericytes and the adjacent interstitium. With the compression of the peritubular capillaries and tubules, hypoxia and physical stress induce pericyte detachment, which could result in extracellular matrix expansion and tubular injury in renal congestion.