title: [Effects of erythropoietin on cardiomyocyte apoptosis and endoplasmic reticulum stress-related proteins in neonatal rats with asphyxia].
abstract: OBJECTIVE
  To study the effects of erythropoietin (EPO) on cardiomyocyte apoptosis and endoplasmic reticulum stress (ERS)-related proteins, glucose-regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP), in neonatal rats with asphyxia.
  
  
  METHODS
  A total of 120 newborn Sprague-Dawley rats (7 days old) were randomly divided into sham-operated (n=40), asphyxia (n=40) and EPO-treated asphyxia groups (n=40). A neonatal rat model of normobaric asphyxia was established in the asphyxia and EPO-treated asphyxia groups. The rats in the EPO-treated asphyxia group received intraperitoneal injection of recombinant human erythropoietin (500 U/mL) immediately after the model was established, while the other two groups received the same volume of normal saline (0.9%). Heart blood and myocardial tissue samples were collected from 8 rats in each group at 2, 6, 12, 24 or 48 hours after the model was established. Serum creatine kinase (CK) and lactate dehydrogenase (LDH) levels were measured; cardiomyocyte apoptosis was evaluated, and expression of myocardial GRP78 and CHOP was measured.
  
  
  RESULTS
  Compared with the sham-operated and EPO-treated asphyxia groups, the asphyxia group had significantly increased serum CK and LDH levels, number of apoptotic cells, and expression of myocardial GRP78 and CHOP at each time point (P<0.01), and all the indices were significantly higher in the EPO-treated asphyxia group than in the sham-operated group (P<0.01). At 24 hours after asphyxia, the expression of myocardial CHOP was positively correlated with the myocardial apoptosis index (r=0.944, P<0.01).
  
  
  CONCLUSIONS
  EPO exerts a protective effect on the myocardium of neonatal rats with hypoxic-ischemic injury by regulating ERS-related proteins GRP78 and CHOP and reducing cardiomyocyte apoptosis.
authors.affiliation: Department of Pediatrics, First Affiliated Hospital of Nanchang University, Nanchang 330006, China. wxh0709@163.com.
authors.forename: Li-Jia
authors.initials: LJ
authors.lastname: Wan
authors.forename: Xing-Heng
authors.initials: XH
authors.lastname: Wu
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects*; D001238:Asphyxia Neonatorum / Q000188:drug therapy* / Q000473:pathology; D003402:Creatine Kinase / Q000097:blood; D000091342:Endoplasmic Reticulum Chaperone BiP; D059865:Endoplasmic Reticulum Stress / Q000502:physiology*; D004921:Erythropoietin / Q000494:pharmacology*; D006360:Heat-Shock Proteins / Q000032:analysis; D007770:L-Lactate Dehydrogenase / Q000097:blood; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D051742:Transcription Factor CHOP / Q000032:analysis
chemical_list: C497251:Ddit3 protein, rat; D000091342:Endoplasmic Reticulum Chaperone BiP; C051684:GRP78 protein, rat; C000717247:HSPA5 protein, human; D006360:Heat-Shock Proteins; D004921:Erythropoietin; D051742:Transcription Factor CHOP; D007770:L-Lactate Dehydrogenase; D003402:Creatine Kinase