Comparison between Radionuclide Ventriculography and Echocardiography for Quantification of Left Ventricular Systolic Function in Rats Exposed to Doxorubicin.
BACKGROUND
Radionuclide ventriculography (RV) is a validated method to evaluate the left ventricular systolic function (LVSF) in small rodents. However, no prior study has compared the results of RV with those obtained by other imaging methods in this context.


OBJECTIVE
To compare the results of LVSF obtained by RV and echocardiography (ECHO) in an experimental model of cardiotoxicity due to doxorubicin (DXR) in rats.


METHODS
Adult male Wistar rats serving as controls (n = 7) or receiving DXR (n = 22) in accumulated doses of 8, 12, and 16 mg/kg were evaluated with ECHO performed with a Sonos 5500 Philips equipment (12-MHz transducer) and RV obtained with an Orbiter-Siemens gamma camera using a pinhole collimator with a 4-mm aperture. Histopathological quantification of myocardial fibrosis was performed after euthanasia.


RESULTS
The control animals showed comparable results in the LVSF analysis obtained with ECHO and RV (83.5 ± 5% and 82.8 ± 2.8%, respectively, p > 0.05). The animals that received DXR presented lower LVSF values when compared with controls (p < 0.05); however, the LVSF values obtained by RV (60.6 ± 12.5%) were lower than those obtained by ECHO (71.8 ± 10.1%, p = 0.0004) in this group. An analysis of the correlation between the LVSF and myocardial fibrosis showed a moderate correlation when the LVSF was assessed by ECHO (r = -0.69, p = 0.0002) and a stronger correlation when it was assessed by RV (r = -0.79, p < 0.0001). On multiple regression analysis, only RV correlated independently with myocardial fibrosis.


CONCLUSIONS
RV is an alternative method to assess the left ventricular function in small rodents in vivo. When compared with ECHO, RV showed a better correlation with the degree of myocardial injury in a model of DXR-induced cardiotoxicity.
Centro de Cardiologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Brazil.
Luciano Fonseca Lemos de
LF
Oliveira
Universidade Federal de Uberlândia, MG, Brazil.
João Lucas
JL
O'Connell
Centro de Cardiologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Brazil.
Eduardo Elias Vieira de
EE
Carvalho
Universidade Federal de Uberlândia, MG, Brazil.
Érica Carolina Campos
ÉC
Pulici
Centro de Cardiologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Brazil.
Minna Moreira Dias
MM
Romano
Centro de Cardiologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Brazil.
Benedito Carlos
BC
Maciel
Centro de Cardiologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Brazil.
Marcus Vinicius
MV
Simões
D000818:Animals; D000903:Antibiotics, Antineoplastic; D066126:Cardiotoxicity / Q000000981:diagnostic imaging; D004195:Disease Models, Animal; D004317:Doxorubicin; D004452:Echocardiography; D005355:Fibrosis; D008297:Male; D015635:Radionuclide Ventriculography; D017208:Rats, Wistar; D012016:Reference Values; D015203:Reproducibility of Results; D018709:Statistics, Nonparametric; D018487:Ventricular Dysfunction, Left / Q000139:chemically induced / Q000000981:diagnostic imaging* / Q000473:pathology; D016277:Ventricular Function, Left / Q000187:drug effects
D000903:Antibiotics, Antineoplastic; D004317:Doxorubicin