[abstract] CHEMOKINE AND CYTOKINE LEVELS AND DECOMPRESSION SICKNESS

Abstract

INTRODUCTION: Preliminary research indicates that non-specific inflammatory responses represent an integral component in the pathological development of decompression sickness (DCS). Elucidation of the potential role(s) of this inflammatory response may lead to pharmacological manipulations to diminish the risk of DCS. The present research investigated the participation of various immune parameters [i.e., cytokines, chemokines, reactive oxygen species (ROS)] in response to exposure to hyperbaric pressure. MATERIAL AND METHODS: Rats (male, Sprague Dawley, n=80) were untreated or treated with the antioxidants alpha-lipoic (ALA) and dihydrolipoic acid (DHLA) 24 h and 30 min prior to being compressed with air (175 fsw) for 1 h followed by rapid ( less than 20 sec) decompression. After 30 min, animals were euthenized and blood was collected for measurement of IL-12 and monocyte chemoattractant protein-1 (MCP-1) by ELISA (Biosource; Camarillo, CA). Statistical analysis of data (mean +/- SEM) was performed by t-test. RESULTS: There were no significant differences between antioxidant-treated and control animals in the incidence of DCS or death. Mean time to onset of symptoms and death was also not statistically different. Antioxidant treatment significantly reduced the levels of IL-12 (871 +/- 51 vs. 672 +/- 44 pg/ml; p = 0.003). There was also a significant difference (p less than 0.001) in IL-12 levels of animals that died (1,092 +/- 76) as compared to those that survived (680 +/- 31 pg/ml). MCP-1 levels were significantly (p = less than 0.05) decreased in treated vs. control animals (158 +/- 14 vs. 189 +/- 12 pg/ml, respectively). There was no difference in MCP-1 levels for animals that died vs. survived. CONCLUSIONS: Elevated levels of proinflammatory cytokines (IL-12) and chemokines (MCP-1) support a role for inflammation in DCS. Additional characterization may identify specific immune-mediated interventions to prevent or delay onset of DCS. This work was funded by work unit number 603706N.00096.133.A0071. Decompression Sickness, Chemokines, Cytokines, antioxidants