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[Myocardial impairment in asphyxiated newborn piglets]
Lin Wu1, Guo-ying Huang, Qi-shan Lin
1Cardiovascular Center, Children's Hospital of Fudan University, Shanghai 200032, China.
Objective:
To establish a piglet model of acute hypoxic myocardial impairment.
Methods:
Nineteen newborn piglets were divided into two groups: control group (CON, n = 8) and asphyxia group (ASP, n = 11). In ASP group, asphyxia was induced by disconnecting the animal from the ventilator and clamping the inhalation tubing for 10 minutes. Six hours after cardiopulmonary resuscitation (CPR), the levels of serum creatine kinase MB (CK-MB) and cardiac troponin T (cTnT) were detected. Cardiac functions were evaluated by echocardiography. Parameters included left ventricular ejection fraction (LVEF), right ventricular ejection fraction (RVEF), ratio of peak E velocity and peak A velocity of mitral flow and tricuspid flow (MVE/A and TVE/A), ratio of peak velocity and a velocity of mitral annulus motion and tricuspid annulus motion (MVe/a and TVe/a), isovolumic relaxation time of left ventricle (LVIRT), index of mitral regurgitation and tricuspid regurgitation (MR and TR). The CON group was examined at the corresponding time points. The pathologic changes in piglets' hearts were examined. The myocardial histopathologic damage score (MHDS) was used to evaluate the severity of myocardial impairments.
Results:
Six hours after CPR, the CK-MB and cTnT in ASP group [(423 +/- 156) IU/L and (0.85 +/- 0.64) microg/L] were both higher than those in CON group [(213 +/- 30) IU/L and (0.08 +/- 0.02) microg/L, P < 0.01]. The LVEF, RVEF, TVE/A, MVe/a and TVe/a in ASP group [(59.6 +/- 8.6)%, (60.2 +/- 7.1)%, 0.79 +/- 0.21, 0.77 +/- 0.12 and 0.78 +/- 0.19, respectively] were all lower than those in CON group [(67.5 +/- 6.9)%, (68.8 +/- 7.4)%, 1.14 +/- 0.16, 1.19 +/- 0.18 and 1.03 +/- 0.27, respectively, P < 0.05]. The MHDS in ASP group was higher (2.82 +/- 0.98) than that in CON group (0.38 +/- 0.53, P < 0.01), but no significant difference was observed in MHDS between the left ventricle and right ventricle.
Conclusion:
Asphyxia can lead to obvious myocardial impairment in newborn piglet, which could be very useful for the studies of acute hypoxic myocardial impairment in the newborn infants.