Rodent Model of Cardiopulmonary Bypass Demonstrates Systemic Inflammation and Neuromarker Changes

The physiologic derangements imposed by cardiopulmonary bypass (CPB) can result in complications such as postoperative delirium. We aim to validate a rodent survival model of CPB demonstrating a systemic inflammatory response and hypothesize that this contributes to post-CPB delirium.

Adult Sprague-Dawley rats were randomized to three groups: 1) Sham peripheral surgical cannulation, 2) CPB followed by acute phase harvest, or 3) CPB followed by 24-h survival. CPB was carried out for 60 min before decannulation and weaning from mechanical ventilation. Physiological and biochemical endpoints were compared between groups. Gene expression analysis of hippocampal tissue was performed using quantitative RT-PCR panels and protein expression levels were confirmed with Western blot.

Sixteen animals underwent cannulation and were successfully decannulated without transfusion requirement or inotrope use with one procedure-related mortality. Serum acute phase proinflammatory chemokines cytokine-induced neutrophil chemoattractant 1, cytokine-induced neutrophil chemoattractant 3, fractalkine, and lipopolysaccharide-induced CXC chemokine as well as interleukin (IL)-10 were increased 1 h following CPB compared to sham (P < 0.05). Significant changes in hippocampal expression of biomarkers apolipoprotein 1, vascular epithelial growth factor A, and synapsin 1 were demonstrated following CPB.

This study validated a model of CPB that captures the resultant systemic inflammatory response, and identified differentially expressed proteins that may be associated with brain injury. Modulation of the CPB-induced inflammatory response may be a promising therapeutic target to attenuate post-CPB delirium, and this survival rat model of CPB with low surgical attrition will allow for more comprehensive evaluations of the short- and long-term effects of both CPB and potential therapeutic interventions.