title: P2X7 receptor antagonism inhibits p38 mitogen-activated protein kinase activation and ameliorates neuronal apoptosis after subarachnoid hemorrhage in rats.
abstract: OBJECTIVE
  Brilliant blue G, a selective P2X7 receptor antagonist, exhibits neuroprotective properties. This study examined whether brilliant blue G treatment ameliorates early brain injury after experimental subarachnoid hemorrhage, specifically via inhibiting p38 mitogen-activated protein kinase-related proapoptotic pathways.
  
  
  METHODS
  Controlled in vivo laboratory study.
  
  
  METHODS
  Animal research laboratory.
  
  
  METHODS
  One hundred fifty-four adult male Sprague-Dawley rats weighing 280-320 g.
  
  
  METHODS
  Subarachnoid hemorrhage was induced in rats by endovascular perforation. Experiment 1 implemented sham-operated rats (sham) and subarachnoid hemorrhage animals, which received vehicle (subarachnoid hemorrhage + vehicle), brilliant blue G (subarachnoid hemorrhage + brilliant blue G), or brilliant blue G plus 2'(3')-O-(4-Benzoylbenzoyl)adenosine 5'-triphosphate (BzATP) (subarachnoid hemorrhage + brilliant blue G + BzATP). The animals were intraperitoneally treated with brilliant blue G (30 mg/kg) at 30 minutes after subarachnoid hemorrhage. BzATP (50 μg/rat), a P2X7 receptor agonist, was intracerebroventricularly administered. Experiment 2 implemented sham-operated rats (sham) and subarachnoid hemorrhage animals, which received vehicle (subarachnoid hemorrhage + vehicle), scramble small interfering RNA (subarachnoid hemorrhage + scramble small interfering RNA), or P2X7 receptor small interfering RNA (subarachnoid hemorrhage + P2X7 receptor small interfering RNA). Subarachnoid hemorrhage grading, neurobehavioral score, and brain edema were evaluated at 24 and 72 hours after surgery. The expression of phosphorylated p38 mitogen-activated protein kinase, phosphorylated extracellular signal-regulated kinases, phosphorylated c-Jun N-terminal kinases, P2X7 receptor, Bcl-2, and cleaved caspase-3 in the left cerebral hemisphere were determined by Western blot. Neuronal apoptosis was examined by double immunofluorescence staining using P2X7 receptor, terminal deoxynucleotidyl transferase-mediated uridine 5'-triphosphate-biotin nick end-labeling, and neuronal nuclei.
  
  
  RESULTS
  Brilliant blue G significantly improved neurobehavioral function and ameliorated brain water content at 24 and 72 hours after subarachnoid hemorrhage. BzATP reversed these treatment effects. Brilliant blue G attenuated neuronal apoptosis in the subcortex, which was associated with decreased expression of phosphorylated p38 mitogen-activated protein kinase and cleaved caspase-3 and an increased expression of Bcl-2 in the left cerebral hemisphere. The beneficial effects of P2X7 receptor small interfering RNA were also mediated by a p38 mitogen-activated protein kinase pathway.
  
  
  CONCLUSIONS
  Inhibition of P2X7 receptor by brilliant blue G or P2X7 receptor small interfering RNA can prevent early brain injury via p38 mitogen-activated protein kinase after subarachnoid hemorrhage.
authors: 1Department of Neurosurgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China. 2Department of Physiology and Pharmacology, Loma Linda University, Loma Linda, CA.
authors: Sheng
authors: S
authors: Chen
authors: Qingyi
authors: Q
authors: Ma
authors: Paul R
authors: PR
authors: Krafft
authors: Yujie
authors: Y
authors: Chen
authors: Jiping
authors: J
authors: Tang
authors: Jianmin
authors: J
authors: Zhang
authors: John H
authors: JH
authors: Zhang
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000627:therapeutic use; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3 / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D008297:Male; D009474:Neurons / Q000502:physiology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D058911:Purinergic P2X Receptor Agonists / Q000627:therapeutic use; D058920:Purinergic P2X Receptor Antagonists / Q000627:therapeutic use*; D034741:RNA, Small Interfering / Q000627:therapeutic use; D051381:Rats; D017207:Rats, Sprague-Dawley; D058486:Receptors, Purinergic P2X7 / Q000235:genetics / Q000378:metabolism; D012394:Rosaniline Dyes / Q000627:therapeutic use*; D013345:Subarachnoid Hemorrhage / Q000188:drug therapy* / Q000201:enzymology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
chemical_list: D019253:Proto-Oncogene Proteins c-bcl-2; D058911:Purinergic P2X Receptor Agonists; D058920:Purinergic P2X Receptor Antagonists; D034741:RNA, Small Interfering; D058486:Receptors, Purinergic P2X7; D012394:Rosaniline Dyes; C033901:3'-O-(4-benzoyl)benzoyladenosine 5'-triphosphate; D000255:Adenosine Triphosphate; D048049:Extracellular Signal-Regulated MAP Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D053148:Caspase 3; C004692:coomassie Brilliant Blue
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