ABSTRACT
OBJECTIVE: A small animal model would be an effective tool for research on the pathophysiology of cardiopulmonary bypass (CPB). However, numerous CPB models do not involve myocardial arrest and resuscitation. The aim of this research is to establish an easily achievable myocardial arrest and resuscitation CPB model through hyperkalemia and landiolol, simulating clinical cardiac surgery. MATERIALS AND METHODS: Ten Sprague-Dawley rats were chosen for CPB. Rats underwent sevoflurane inhalation induction anesthesia and were sustained in an anesthesia state by intubation and intraperitoneal injection's of esketamine and propofol. The entire CPB circuit include a reservoir, a membrane oxygenator and a roller pump, which were connected into a complete loop via silicon tubes and infusion tube.After CPB was established through the tail artery and internal jugular vein, cardioplegic arrest was induced and maintained for 5 min at a rectum temperature of 28.5 ± 0.5°C with hyperkalemia and landiolol. Calcium chloride, epinephrine and insulin were then used for resuscitation. RESULT: All rats successfully finished cardioplegic arrest, resuscitation procedure and survived 2 h postoperatively. Mean hematocrit during CPB was significantly lower than physiologic values of the baseline. The mean time of arrest-resuscitation and CPB was 5.4 ± 0.8 min and 98.5 ± 5.0 min. The blood gas at each detection point were in range with the normal standard requirement of CPB. CONCLUSION: The establishment of cardioplegic arrest and resuscitation procedure via hyperkalemia and landiolol during CPB of WD rat could be achieved successfully. This animal model could be an alternative organ injury research on organ injury of patients undergoing cardiac surgery.
ABSTRACT
Congenital heart defects (CHDs), the most common congenital human birth anomalies, involves complex genetic factors. Wnt/ß-catenin pathway is critical for cardiogenesis and proved to be associated with numerous congenital heart abnormities. AXIN2 has a unique role in Wnt/ß-catenin pathway, as it is not only an important inhibitor but also a direct target of Wnt/ß-catenin pathway. However, whether AXIN2 is associated with human CHDs has not been reported. In our present study, we found a differential expression of Axin2 mRNA during the development of mouse heart, indicating its importance in mouse cardiac development. Then using targeted next-generation sequencing, we found two novel case-specific rare mutations [c.28 C > T (p.L10F), c.395 A > G (p.K132R)] in the sequencing region of AXIN2. In vitro functional analysis suggested that L10F might be a loss-of-function mutation and K132R is a gain-of-function mutation. Both mutations disrupted Wnt/ß-catenin pathway and failed to rescue CHD phenotype caused by Axin2 knockdown in zebrafish model. Collectively, our study indicates that rare mutations in AXIN2 might contribute to the risk of human CHDs and a balanced canonical Wnt pathway is critical for cardiac development process. To our knowledge, it is the first study of AXIN2 mutations associated with human CHDs, providing new insights into CHD etiology.
