Evaluation of the mitochondrial respiration of cardiac myocytes in rats submitted to mechanical bile duct obstruction.
OBJECTIVE
The objective of the present study was to evaluate the capacity of the myocardium for energy production by the analysis of mitochondrial respiration in rats with jaundice submitted to bile duct ligature.


METHODS
Sixteen male Wistar rats were divided into 2 Groups: Group SO submitted to nontherapeutic laparotomy (sham operation) and Group IC (icteric group) submitted to bile duct ligature. After 7 days, laparotomy was again performed in all animals for cardiac muscle extraction and analysis. Mitochondrial oxygen consumption was determined by stage 3 velocity and stage 4 velocity. The respiratory control ratio (RCR) was obtained by the ratio of stage 3 to stage 4 velocity. Statistical analysis was performed by the Mann-Whitney test, with the level of significance set at 5% (p<0.05).


RESULTS
Statistical analysis revealed a significant drop in oxygen consumption during stage 3 mitochondrial respiration in group IC compared with SO, whereas the values obtained during stage 4 were basically identical for the two groups. Likewise, RCR values exhibited a significant reduction.


CONCLUSIONS
The cellular respiration of the "jaundiced heart" is depressed. This was demonstrated by the reduced capacity of cardiac mitochondria to consume oxygen and synthesize ATP, supporting the idea of a latent cardiac impairment responsible for the hemodynamic decompensation occurring during cholestasis.
Division of Digestive Surgery, Department of Surgery and Anatomy, Ribeirão Preto Faculty of Medicine, University of São Paulo, SP, Brazil. rafaelkemp@terra.com.br
Rafael
R
Kemp
Orlando de
Od
Castro-e-Silva
José Sebastião dos
JS
Santos
Ajith Kumar
AK
Sankarankutty
Rodrigo Borges
RB
Correa
Caroline Floreoto
CF
Baldo
Maria Elisa Jordani
ME
Souza
Maria Cecilia
MC
Jordani
D000818:Animals; D019069:Cell Respiration / Q000502:physiology*; D001651:Cholestasis, Extrahepatic / Q000150:complications / Q000503:physiopathology*; D004195:Disease Models, Animal; D041781:Jaundice, Obstructive / Q000150:complications / Q000503:physiopathology*; D008026:Ligation; D008297:Male; D008929:Mitochondria, Heart / Q000502:physiology*; D032383:Myocytes, Cardiac / Q000378:metabolism / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar