A rat model to investigate quality of recovery after abdominal surgery

INTRODUCTION: Major advances in therapies to optimize recovery after surgery have been limited by the lack of an animal model that can mimic major domains of postoperative sickness behavior in humans. We hypothesized that the integration of commonly impaired domains of quality of recovery in humans could be reproduced in a rat model. OBJECTIVES: To create a rat model that can mimic surgical recovery in humans. METHODS: Adult male Sprague-Dawley rats were used in the development of a quality of recovery score after surgery. Six physiological parameters or behaviors were tested in naive, sham, and laparotomized animals. A quality of recovery score was constructed and ranged from 18 (no impairment) to 0 (gross impairment). We treated animals with a nutraceutical intervention consisting of aspirin and eicosapentaenoic acid. Inflammatory markers and specialized proresolving mediators were measured in serum and the intestinal mucosa of rats, respectively. RESULTS: We observed a significant reduction in quality of recovery scores on postoperative days 1 (median, interquartile: 6 [4.75–8.25] vs naive rats: 17.5 [15.5–18]), 2 (median, interquartile: 13 [11.25–13.25], P < 0.001 vs naive rats: 17 [17–18], P = 0.001), and 3 (median, interquartile: 14.5 [13.5–16] vs naive rats: 17 [15.75–18], P < 0.02). Surgery promoted a significant increase in the concentrations of inflammatory cytokines, but it reduced levels of interleukin-12p70 and macrophage colony-stimulating factor. Lipoxin B4 and 13-HODE were significantly higher in laparotomized rats. Aspirin + eicosapentaenoic acid substantially improved recovery scores and modulated the postsurgical inflammatory response. CONCLUSION: Our novel rat model can be used to study mechanisms governing surgical recovery in rats.