The Specific Protein Kinase R (PKR) Inhibitor C16 Protects Neonatal Hypoxia-Ischemia Brain Damages by Inhibiting Neuroinflammation in a Neonatal Rat Model

Med Sci Monit. 2016 Dec 23:22:5074-5081. doi: 10.12659/msm.898139.

Abstract

BACKGROUND Brain injuries induced by hypoxia-ischemia in neonates contribute to increased mortality and lifelong neurological dysfunction. The specific PKR inhibitor C16 has been previously demonstrated to exert a neuroprotective role in adult brain injuries. However, there is no recent study available concerning its protective role in hypoxia-ischemia-induced immature brain damage. Therefore, we investigated whether C16 protects against neonatal hypoxia-ischemia injuries in a neonatal rat model. MATERIAL AND METHODS Postnatal day 7 (P7) rats were used to establish classical hypoxia-ischemia animal models, and C16 postconditioning with 100 ug/kg was performed immediately after hypoxia. Western blot analysis was performed to quantify the phosphorylation of the PKR at 0 h, 3 h, 6 h, 12 h, 24 h, and phosphorylation of NF-κB 24h after hypoxia exposure. The TTC stain for infarction area and TUNEL stain for apoptotic cells were assayed 24 h after the brain hypoxia. Gene expression of IL-1β, IL-6, and TNF-α was performed at 3 h, 6 h, 12 h, and 24 h. RESULTS The level of PKR autophosphorylation was increased dramatically, especially at 3 h (C16 group vs. HI group, P<0.01). Intraperitoneal C16 administration reduced the infarct volume and apoptosis ratio after this insult (C16 group vs. HI group<0.01), and C16 reduced proinflammatory cytokines mRNA expression, partly through inhibiting NF-κB activation (C16 group vs. HI group<0.05). CONCLUSIONS C16 can protect immature rats against hypoxia-ischemia-induced brain damage by modulating neuroinflammation.

MeSH terms

  • Animals
  • Animals, Newborn
  • Apoptosis / drug effects
  • Brain
  • Cytokines / genetics
  • Cytokines / metabolism
  • Disease Models, Animal
  • Hypoxia-Ischemia, Brain / complications
  • Hypoxia-Ischemia, Brain / pathology
  • Hypoxia-Ischemia, Brain / prevention & control*
  • Indoles / administration & dosage
  • Indoles / pharmacology
  • Indoles / therapeutic use*
  • Inflammation / complications
  • Inflammation / drug therapy*
  • Inflammation / pathology
  • Injections, Intraperitoneal
  • Male
  • NF-kappa B / metabolism
  • Neurons / drug effects
  • Neurons / pathology
  • Neuroprotective Agents / administration & dosage
  • Neuroprotective Agents / pharmacology
  • Neuroprotective Agents / therapeutic use*
  • Phosphorylation / drug effects
  • Protein Kinase Inhibitors / administration & dosage
  • Protein Kinase Inhibitors / pharmacology*
  • Protein Kinase Inhibitors / therapeutic use
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Rats, Sprague-Dawley
  • Thiazoles / administration & dosage
  • Thiazoles / pharmacology
  • Thiazoles / therapeutic use*
  • eIF-2 Kinase / antagonists & inhibitors*
  • eIF-2 Kinase / metabolism

Substances

  • Cytokines
  • GW 506033X
  • Indoles
  • NF-kappa B
  • Neuroprotective Agents
  • Protein Kinase Inhibitors
  • RNA, Messenger
  • Thiazoles
  • eIF-2 Kinase