Beta-1 blocker reduces inflammation and preserves intestinal barrier function after open abdominal surgery

Open abdominal surgery is frequently related to excessive inflammation and a compromised intestinal barrier, leading to poor clinical outcomes. The administration of beta-1 blocker has been shown to effectively reduce inflammation and preserve intestinal barrier function in patients with sepsis, shock, or other critical illnesses. The underlying mechanism of these effects may be associated with the autonomic nervous system's activation via cholecystokinin receptors. This study aimed to investigate the effect of beta-1 blocker on systemic and local inflammatory responses and the intestinal barrier function in the context of open abdominal surgery.A rat model of open abdominal surgery was induced through peritoneal air exposure for 3 hours and treated via gavage with the beta-1 blocker, metoprolol, or saline. Cholecystokinin-receptor antagonists were administered before the metoprolol treatment. Peritoneal lavage fluid, serum, and tissues were collected 24 hours after surgery to determine systemic and local inflammation and intestinal integrity.The intervention with metoprolol significantly reduced serum tumor necrosis factor-alpha and interleukin-6 (P.05) and peritoneal interleukin-6 (P.01) compared with those of animals treated with saline. The intestinal myeloperoxidase indicating the influx of neutrophils was also significantly prevented by the administration of metoprolol (P.05). Above all, this intervention resulted in a significant decrease in serum D-lactate and intestinal fatty acid-binding protein, intestinal permeability, bacterial translocation, and Chiu's score for intestinal mucosa injury (P.05). However, the anti-inflammatory and intestinal integrity protective effects of metoprolol were prevented by the blockage of cholecystokinin receptors (P.05).Our data indicate that beta-1 blocker reduces systemic and local inflammatory responses and preserves intestinal barrier function after open abdominal surgery through a mechanism that depends on cholecystokinin receptors. Clinically, these findings imply that perioperative intervention with a beta-1 blocker may be an effective new therapy to enhance recovery after open abdominal surgery.