Changes in expression of keratin genes in renal tissues during renal ischemia-reperfusion injury in mice

Abstract

Objective To investigate the changes in the expression of keratin genes in renal tissues during renal ischemia-reperfusion(I/R)injury in mice. Methods Six wild type male C57/B6 mice, aged 50 days, weighing 20-30 g, were divided into 2 groups(n=3 each)using a random number table: sham operation group(Sham group)and I/R group.Right renal arteries and veins were clamped for 1 h followed by reperfusion, and the left kidneys were removed to establish the model of renal I/R injury.At 24 h of reperfusion, blood samples were collected from the left ventricle for determination of serum creatinine and urea nitrogen concentrations by colorimetric method.The right kidney specimens were obtained for pathologic examination and for determination of the expression of kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin mRNA(by quantitative real-time polymerase chain reaction [qRT-PCR]) and keratin genes(by Affemetrixc DNA microarray). The differentially expressed genes identified were further confirmed by qRT-PCR. Results Compared with Sham group, the serum creatinine and urea nitrogen concentrations were significantly increased, the expression of kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin mRNA was up-regulated(P<0.05), and the damage to the renal tubules was aggravated in I/R group.The results of microarray analysis showed that only keratin 20 gene(the expresion was up-regulated)was the differentially expressed gene(P<0.05), and the results measured by qRT-PCR were consistent with those measured by Affemetrixc DNA microarray. Conclusion Keratin 20 gene expression in renal tissues is up-regulated during renal I/R injury in mice, and the change may be involved in the endogenous protective mechanism during renal I/R injury. Key words: Keratins; Reperfusion injury; Kidney