Expression of E-selectin mRNA during ischemia/reperfusion injury

To better understand molecular and cellular processes involved in tissue inflammation, we have examined expression of endothelial leukocyte adhesion molecule 1 (E-selectin) mRNA in adult male rats after ischemia/reperfusion (I/R) injury and after intravenous injection of lipopolysaccharide (LPS). The polymerase chain reaction was used to generate a rat E-selectin cDNA fragment by using heart total RNA from rats exposed to LPS. This partial cDNA fragment spanned sequences from complement repeat region-5 to the second cytoplasmic tail domain. Comparison of the predicted amino acid sequence from the rat cDNA fragment to mouse and human E-selectin protein sequences showed significant conservation. The rat E-selectin cDNA fragment was used as a probe to examine the regulation of E-selectin mRNA expression by Northern blot analysis. As previously described in other animal species, E-selectin mRNA expression was induced after intravenous injection of LPS. In contrast, ischemia did not induce E-selectin mRNA expression, except in the setting of I/R injury. I/R injury triggered expression of E-selectin mRNA in the kidney. These experiments represent a first in vivo examination of E-selectin mRNA expression after I/R injury and constitute an initial step in characterizing a model system for investigating inflammation in the setting of acute ischemic injury.