Increased O-linked β-N-acetylglucosamine levels on proteins improves survival, reduces inflammation and organ damage 24 hours after trauma-hemorrhage in rats

Abstract

To evaluate the effects of O-linked beta-N-acetylglucosamine (O-GlcNAc) levels on survival, inflammation, and organ damage 24 hrs after trauma-hemorrhage. We have previously shown that increasing protein O-GlcNAc levels by different mechanisms reduced inflammatory responses and improved organ function 2 hrs after trauma-hemorrhage. Prospective, randomized, controlled study. Animal research laboratory. Male, adult Sprague-Dawley rats. Overnight fasted animals were subjected to either sham surgery or trauma-hemorrhage and during the resuscitation phase received glucosamine (270 mg/kg) to increase O-GlcNAc synthesis or O-(2-acetamido-2-deoxy-D-glucopyranosylidene) amino N-phenyl carbamate (PUGNAc, 7 mg/kg) to inhibit O-GlcNAc removal, or mannitol as control. Survival was followed up for 24 hrs. Surviving rats were euthanized and inflammatory responses, and end organ injuries were assessed. Both glucosamine and PUGNAc increased 24-hr survival compared with controls (control: 53%, GN: 85%, PUGNAc: 86%, log-rank test, p < .05). PUGNAc attenuated the trauma-hemorrhage-induced increase in serum interleukin-6 (sham surgery: 8 +/- 6, control: 181 +/- 36, PUGNAc: 42 +/- 22 pg/mL, p < .05), alanine transaminase (sham surgery: 95 +/- 14, control: 297 +/- 56, PUGNAc: 126 +/- 21 IU, p < .05), aspartate transaminase (sham surgery: 536 +/- 110, control: 1661 +/- 215, PUGNAc: 897 +/- 155 IU, p < .05), and lactate dehydrogenase (sham surgery: 160 +/- 18, control: 1499 +/- 311, PUGNAc: 357 +/- 99 IU, p < .05); however, glucosamine had no effect on these serum parameters. Furthermore, PUGNAc but not glucosamine maintained O-GlcNAc levels in liver and lung and significantly attenuated the NF-kappaB DNA activation in the liver. In the liver and heart, increased inducible nitric oxide synthase expression was also attenuated in the PUGNAc-treated group. These results demonstrate that increasing O-GlcNAc with either glucosamine or PUGNAc improved 24-hr survival after trauma-hemorrhage. However, only PUGNAc treatment attenuated significantly the subsequent tissue injury and inflammatory responses, suggesting that inhibition of O-GlcNAc removal may represent a new therapeutic approach for the treatment of hypovolemic shock.