title: Pregnancy-induced physiological hypertrophy protects against cardiac ischemia-reperfusion injury.
abstract: OBJECTIVE
  Cardiac hypertrophy is a compensatory response of the heart to maintain its pumping capacity. Cardiac hypertrophy can be divided into pathological hypertrophy and physiological hypertrophy. The major forms of physiological hypertrophy include developing in response to developmental maturation, exercise, and pregnancy, which is adaptive and beneficial. Exercise has well-known beneficial cardiovascular effects and has recently been shown to be protective for myocardial ischemia-reperfusion injury. However, there are conflicting reports for the cardiac protective effects of pregnancy-induced hypertrophy. In the present study, we investigated the effects of pregnancy-induced physiological hypertrophy in cardiac ischemia-reperfusion injury and if cardiac progenitor cells were activated during pregnancy.
  
  
  METHODS
  Physiological hypertrophy was induced in pregnancy and the mRNA levels of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) were determined by real-time polymerase chain reactions (RT-PCRs) analysis. Triphenyltetrazolium chloride staining was used to determine the cardiac ischemia-reperfusion injury. c-Kit and Nkx2.5 levels were determined by RT-PCRs, western blot and immunofluorescent staining.
  
  
  RESULTS
  Heart weight (HW) and the ratio of HW to tibia length were increased while mRNA levels of ANP and BNP remained unchanged. Pregnancy-induced physiological hypertrophy protected against cardiac ischemia-reperfusion injury. In pregnancy, c-Kit positive cardiac progenitor cells were activated.
  
  
  CONCLUSIONS
  This study presents that pregnancy-induced physiological hypertrophy activates cardiac progenitor cells and thereafter protects against cardiac ischemia-reperfusion injury.
authors.affiliation: Regeneration Lab and Experimental Center of Life Sciences, Shanghai University Shanghai 200444, China ; Shanghai Key Laboratory of Bio-Energy Crops, School of Life Science, Shanghai University Shanghai 200444, China.
authors.forename: Junjie
authors.initials: J
authors.lastname: Xiao
authors.affiliation: Regeneration Lab and Experimental Center of Life Sciences, Shanghai University Shanghai 200444, China ; Shanghai Key Laboratory of Bio-Energy Crops, School of Life Science, Shanghai University Shanghai 200444, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Li
authors.affiliation: Regeneration Lab and Experimental Center of Life Sciences, Shanghai University Shanghai 200444, China ; Shanghai Key Laboratory of Bio-Energy Crops, School of Life Science, Shanghai University Shanghai 200444, China.
authors.forename: Tianzao
authors.initials: T
authors.lastname: Xu
authors.affiliation: Regeneration Lab and Experimental Center of Life Sciences, Shanghai University Shanghai 200444, China ; Shanghai Key Laboratory of Bio-Energy Crops, School of Life Science, Shanghai University Shanghai 200444, China.
authors.forename: Dongcao
authors.initials: D
authors.lastname: Lv
authors.affiliation: Shanghai Entry-Exit Inspection and Quarantine Bureau Shanghai 200135, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Shen
authors.affiliation: Tongji University School of Medicine Shanghai 200065, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Song
authors.affiliation: Department of Cardiology, Shanghai Tongji Hospital, Tongji University School of Medicine Shanghai 200065, China.
authors.forename: Jiahong
authors.initials: J
authors.lastname: Xu
mesh_terms: D000818:Animals; D009320:Atrial Natriuretic Factor / Q000096:biosynthesis; D015153:Blotting, Western; D005260:Female; D005455:Fluorescent Antibody Technique; D006321:Heart / Q000033:anatomy & histology* / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D015428:Myocardial Reperfusion Injury / Q000378:metabolism; D020097:Natriuretic Peptide, Brain / Q000096:biosynthesis; D009929:Organ Size; D011247:Pregnancy / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D012333:RNA, Messenger; D020097:Natriuretic Peptide, Brain; D009320:Atrial Natriuretic Factor
keywords: Pregnancy; cardiac progenitor cells; hypertrophy; ischemia/reperfusion; physiological