cDNA profiling in leukocytes exposed to hypertonic resuscitation fluids

Abstract

Background: Resuscitative fluids induce distinctive changes in leukocyte functions: incubation with colloid Dextran increases production of reactive oxygen species and adhesion, whereas exposure to hypertonic saline (HTS) inhibits "oxidative burst" and phagocytosis. In hypertonic saline Dextran (HTD), the hypertonic component determines the leukocyte functional behavior and subsequently activation response. We investigated whether leukocyte gene expression is analogously affected.

Methods: Whole blood from eight volunteers was diluted and incubated for 30 min at 37(o)C in 6.0% Dextran-70, 7.5% HTS, and 7.5% HTD. Total leukocyte RNA was extracted and used to synthesize biotinylated cDNA probes. Each probe was individually hybridized to a cDNA array to simultaneously measure the expression of 23 genes involved in inflammation, cell migration, and apoptosis.

Results: Leukocytes incubated with Dextran-70 demonstrated greater than a 6-fold (p < 0.05) increase in the expression of interleukin-8, growth-regulated oncogenes alpha and beta, L-selectin, superoxide dismutase, tumor necrosis factor-alpha (TNF-alpha), and mitogen-activated protein kinase 3. The expression profile induced by HTS was not significantly different from that of unstimulated blood, except for prominent induction of only three genes. HTD attenuated the expression of Dextran-70 upregulated genes, although the level of their expression was higher than in HTS-treated leukocytes.

Conclusions: Hypertonic resuscitation fluids diminish the expression of immune activation-associated genes. Hypertonic component of HTD determines the leukocyte gene expression profile.