Anastomotic leaks remain one of the most dreaded complications in gastrointestinal surgery causing significant morbidity, that negatively affect the patients' quality of life. Experimental studies play an important role in understanding the pathophysiological background of anastomotic healing and there are still many fields that require further investigation. Knowledge drawn from these studies can lead to interventions or techniques that can reduce the risk of anastomotic leak in patients with high-risk features. Despite the advances in experimental protocols and techniques, designing a high-quality study is still challenging for the investigators as there is a plethora of different models used.

To review current state of the art for experimental protocols in high-risk anastomosis in rats.

This systematic review was performed according to The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. To identify eligible studies, a comprehensive literature search was performed in the electronic databases PubMed (MEDLINE) and Scopus, covering the period from conception until 18 October 2023.

From our search strategy 102 studies were included and were categorized based on the mechanism used to create a high-risk anastomosis. Methods of assessing anastomotic healing were extracted and were individually appraised.

Anastomotic healing studies have evolved over the last decades, but the findings are yet to be translated into human studies. There is a need for high-quality, well-designed studies that will help to the better understanding of the pathophysiology of anastomotic healing and the effects of various interventions.

Genistein is a natural isoflavonoid and has several pharmacological effects, such as antioxidant, antitumor activity, and improvement of glucose metabolism. The safety of intestinal anastomosis after ischemia-reperfusion (I/R) injury is a critical issue for surgeons. This experimental study aimed to investigate the effects of genistein on anastomotic healing after intestinal I/R injury.

A total of 36 male Wistar Albino rats were divided into four groups: control, I/R, genistein, and genistein + I/R. The control group received segmental ileal resection and ileoileal anastomosis. The I/R group received resection + anastomosis after intestinal I/R. The genistein group was administered subcutaneous injection of 1 mg/kg genistein 12 h and 1 h before the procedure and received ileal resection + anastomosis. The genistein + I/R group received I/R + ileal resection + anastomosis after genistein injection. Anastomotic bursting pressure, hydroxyproline, superoxide dismutase, and glutathione peroxidase levels and histopathological wound healing scores of all rats were measured on postoperative day 5.

The anastomotic bursting pressure was significantly higher in the genistein and genistein + I/R groups (P < 0.001). Genistein increased the hydroxyproline concentration and the superoxide dismutase and glutathione peroxidase levels in the intestinal anastomosis (P < 0.001). In histopathological assessment, the mean wound healing score was significantly higher in the genistein group than in the other groups (P < 0.001).

Genistein, with its anti-inflammatory and antioxidant properties, shows protective effects against increased oxidative stress after intestinal I/R injury and contributes positively to intestinal anastomotic healing.