Post-operative course in a surgical model of acute myocardial infarction in the rabbit

Abstract

This study was undertaken to evaluate the post-operative (post-OP) course of rabbits in a surgical model of myocardial infarction (MI). Ten New Zealand White rabbits were subjected to coronary artery ligation after lateral thoracotomy. Anesthesia was delivered using a xylazine–ketamine–isoflurane protocol after endotracheal intubation. Among other cardiorespiratory parameters, arterial pressure was monitored via central ear artery catheterization. Post-OP care included oxygen, antibiotic and analgesic treatment as well as nutritional and fluid support. A series of cardiorespiratory, hematological, blood biochemical and clinical parameters were assessed during the first 21 days. The mortality rate was 10%. Hypotension and hypothermia, noted during the operation, reverted within the first few post-MI hours. Electrocardiographic alterations, which included ST segment elevation and Q wave, appeared after MI and remained throughout the study period. Tachycardia was observed during the first 5 days. Hematological examination revealed mild and transient anemia during the post-OP period and leucocytosis up to the 5th day. Urea was increased up to the 12th post-MI hour while increased AST, ALT, LDH and CK levels normalized by the first 4–5 days. Although the post-OP anorexia period lasted around 5 days, the animals did not manage to regain their body weight by the end of the study period. In conclusion, the present model offers a low mortality rate and could be useful in mid- or long-term MI studies. The animals go through a critical post-OP period of around 5 days during which special care should be given. After that time, their clinical and blood laboratory parameters tend to normalize.