Early postoperative oral intake accelerates upper gastrointestinal anastomotic healing in the rat model.

BACKGROUND In our previous study, we reported that early postoperative oral feeding accelerated upper gastrointestinal anastomotic healing in rats. To investigate its underlying mechanism, we performed in vivo and in vitro experiments. MATERIALS AND METHODS Rats that received proximal jejunal anastomosis were divided into four groups: the enteral nutrition (EN) group were fed via gastrostomy, the total parental nutrition (TPN alone) group were fed via a venous catheter, the TPN + saline group received an additional administration of normal saline solution via gastrostomy, and the TPN + water group received an additional administration of distilled water via gastrostomy. The anastomotic bursting pressure (ABP) and the hydroxyproline content of the anastomotic tissue were measured 5 d postoperatively. In an in vitro setting, the rat gastrointestinal fibroblasts were subjected to uniaxial stretching for 60 min, and the expression of type I and type III collagen mRNA was evaluated. RESULTS The ABP and hydroxyproline content in the EN group, the TPN + saline group, and the TPN + water group were significantly higher than those in the TPN alone group (ABP; 214.6 ± 42, 199.4 ± 36, and 187.3 ± 29 versus 149.5 ± 49 mmHg; P < 0.01, hydroxyproline; 63.5 ± 10, 67.8 ± 13, and 64.1 ± 14 versus 50.5 ± 12 μmol/g dry tissue; P < 0.01). The mRNA levels of type I and type III collagen were increased by stretch stimulation. CONCLUSIONS These results suggest that mechanical loading plays a key role in anastomotic healing. Further investigations are necessary to confirm this suggestion.