Rat heterotopic cardiac transplantation

Heterotopic cardiac transplants were done using a published technique[14]. Cardiac function was assessed daily by abdominal palpation and transplant electrocardiography. The end point of cardiac transplant survival was defined as the last day of palpable heart beating. Care of all rats in this study complied with the Animal Research Act 1985 (NSW, Australia). The protocols were designed to minimise pain and discomfort to the animals. Animals were acclimatised to laboratory conditions (22 °C, 12 h cycle of light and dark, 50% humidity, ad libitum access to food and water) for a minimum of 1 wk prior to experimentation. Intragastric gavage administration was carried out with conscious animals, using curved gavage needles appropriate for animal size (250-300 gm body weight: Gauge 16, 100 mm). All transplanted rats were given post-operative analgesia (Carprofen 4 mg/kg every 12-24 h subcutaneously). They were euthanized by approved carbon dioxide asphyxiation when survival reached 100 d or when the heart stopped beating confirmed by electrocardiography prior to tissue procurement.