Researchers have developed a novel rat model for studying cardiac surgery and cardioprotective strategies. The study, published in the journal Scientific Reports, found that a specific cardioplegia solution called histidine-tryptophan-ketoglutarate (HTK) was superior to other commonly used solutions in reducing inflammatory response and preserving heart function in this model. This compact animal model could help advance our understanding of myocardial ischemia-reperfusion injury and test new cardioprotective treatments. The findings have important implications for improving outcomes in cardiac surgery patients.
Establishing a Practical Rat Model for Cardiac Surgery
Researchers in this study aimed to develop a rat model that closely mimics the clinical scenario of cardiac surgery, including the use of cardiopulmonary bypass (CPB) and cardiac arrest and resuscitation. Existing animal models for cardiac surgery often had limitations, such as not fully replicating the complexities of the clinical procedure or requiring specialized expertise and resources.
The researchers established a rat model using a right thoracotomy approach, which allowed them to perform cardiac arrest and resuscitation while minimizing trauma and bleeding compared to the traditional midline sternotomy. This compact CPB system, with a total volume of less than 8 mL, does not require priming with blood and can be maintained at a flow rate of 100-150 mL/kg/min.
Evaluating the Cardioprotective Effects of Different Cardioplegia Solutions
The researchers compared the myocardial protective effects of three different cardioplegia solutions: histidine-tryptophan-ketoglutarate (HTK), 4:1 blood cardioplegia (BC), and del Nido cardioplegia (DN). These solutions differ in their composition and mechanisms of action, and their relative efficacy in preserving heart function during cardiac surgery remains an active area of research.
The study found that the HTK cardioplegia group exhibited significantly lower histopathological scores, indicating less severe myocardial damage, compared to the BC and DN groups. Additionally, the levels of creatine kinase (CK) and creatine kinase MB (CKMB), which are markers of myocardial injury, were lower in the HTK group at 2 hours after weaning off CPB.
Reduced Inflammatory Response with HTK Cardioplegia
Cardiopulmonary bypass can trigger a systemic inflammatory response, which can contribute to postoperative complications. The researchers evaluated the expression of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α), two key inflammatory cytokines, in the myocardial tissue.
The results showed that the HTK group had significantly lower levels of IL-6 and TNF-α compared to the BC and DN groups, suggesting that HTK cardioplegia was more effective in attenuating the inflammatory response associated with cardiac surgery.
Implications and Future Directions
This compact rat model of cardiac surgery with CPB and cardiac arrest/resuscitation could serve as a valuable tool for studying Click Here
