Effect of acidosis on IL-8 and MCP-1 during hypoxia and reoxygenation in human NT2-N neurons

Abstract

Inflammation probably plays a significant role in perinatal brain injury. To study the contribution of locally produced cytokines, the effect on cell death of addition of IL-8 and MCP-1 or antibodies to these, and the impact of acidosis, human postmitotic NT2-N neurons were exposed to 3 h of hypoxia and glucose deprivation and reoxygenated for 21 h. After 3 h of hypoxia with neutral medium, IL-8 was significantly increased compared to controls (150 (100–250)% vs. 100 (85–115)%, p = 0.023). After 21 h of neutral reoxygenation, both IL-8 (380 (110–710)% vs. 150 (85–260)%, p = 0.041) and monocyte chemoattractant protein-1 (MCP-1) (650 (440–2000)% vs. 310 (230–340)%, p = 0.007) were significantly increased compared to controls. After 3 h of hypoxia, both IL-8 ( p = 0.002) and MCP-1 ( p = 0.008) were significantly lower in cells with acidotic compared with cells with neutral medium. Acidosis during reoxygenation, however, significantly increased IL-8 release, whereas MCP-1 release was diminished. Similar effects of acidosis were seen in normoxic controls. The cells also secreted RANTES and IP-10, but not 8 other cytokines tested. We found no effect on cell death, measured by MTT assay, of addition of IL-8, MCP-1 or antibodies to these. We conclude that human NT2-N neurons release IL-8 and MCP-1 during 21 h of reoxygenation after 3 h of hypoxia. Acidosis led to a differential effect on IL-8 and MCP-1, with increased IL-8 and decreased MCP-1, both during reoxygenation and in normoxic controls. IL-8 and MCP-1 had no effect on cell death.