title: Transthoracic echocardiography reference values in juvenile and adult 129/Sv mice.
abstract: BACKGROUND
  In the recent years, the use of Doppler-echocardiography has become a standard non-invasive technique in the analysis of cardiac malformations in genetically modified mice. Therefore, normal values have to be established for the most commonly used inbred strains in whose genetic background those mutations are generated. Here we provide reference values for transthoracic echocardiography measurements in juvenile (3 weeks) and adult (8 weeks) 129/Sv mice.
  
  
  METHODS
  Echocardiographic measurements were performed using B-mode, M-mode and Doppler-mode in 15 juvenile (3 weeks) and 15 adult (8 weeks) mice, during isoflurane anesthesia. M-mode measurements variability of left ventricle (LV) was determined.
  
  
  RESULTS
  Several echocardiographic measurements significantly differ between juvenile and adult mice. Most of these measurements are related with cardiac dimensions. All B-mode measurements were different between juveniles and adults (higher in the adults), except for fractional area change (FAC). Ejection fraction (EF) and fractional shortening (FS), calculated from M-mode parameters, do not differ between juvenile and adult mice. Stroke volume (SV) and cardiac output (CO) were significantly different between juvenile and adult mice. SV was 31.93 ± 8.67 μl in juveniles vs 70.61 ± 24.66 μl in adults, ρ < 0.001. CO was 12.06 ± 4.05 ml/min in juveniles vs 29.71 ± 10.13 ml/min in adults, ρ < 0.001. No difference was found in mitral valve (MV) and tricuspid valve (TV) related parameters between juvenile and adult mice. It was demonstrated that variability of M-mode measurements of LV is minimal.
  
  
  CONCLUSIONS
  This study suggests that differences in cardiac dimensions, as wells as in pulmonary and aorta outflow parameters, were found between juvenile and adult mice. However, mitral and tricuspid inflow parameters seem to be similar between 3 weeks and 8 weeks mice. The reference values established in this study would contribute as a basis to future studies in post-natal cardiovascular development and diagnosing cardiovascular disorders in genetically modified mouse mutant lines.
authors: Regenerative Medicine Program, Department of Biomedical Sciences and Medicine (DCBM), University of Algarve (UALG), Campus of Gambelas, Edf.8, 8005-139, Faro, Portugal.
authors: Maurícia
authors: M
authors: Vinhas
authors: Ana Carolina
authors: AC
authors: Araújo
authors: Sónia
authors: S
authors: Ribeiro
authors: Luís Brás
authors: LB
authors: Rosário
authors: José António
authors: JA
authors: Belo
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D004195:Disease Models, Animal; D015150:Echocardiography, Doppler / Q000379:methods*; D006330:Heart Defects, Congenital / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006352:Heart Ventricles / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008297:Male; D051379:Mice; D057507:Mice, 129 Strain; D012016:Reference Values; D016277:Ventricular Function, Left / Q000502:physiology*
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