Impact of the negative endoluminal pressure on gastric healing: an in vivo study

The biological effects of vacuum therapy on gastrointestinal healing remain poorly understood. This work aims to evaluate the effects of negative endoluminal pressure on gastric healing.

34 Wistar rats underwent gastric incision and were allocated into four groups: Group 1 (n = 10), incision only; Group 2 (n = 10), incision plus gastrostomy without vacuum; Group 3 (n = 7), incision plus vacuum therapy at -100 mmHg; and Group 4 (n = 7), at -300 mmHg. Animals remained restrained for 48 hours before euthanasia. Macroscopic and histopathological outcomes-gastritis, hemorrhage, adhesions, leak, mucosal erosion, fibrosis, and angiogenesis-were assessed using semi-quantitative scores. A composite healing score was calculated by summing fibrosis and angiogenesis and subtracting necrosis and hemorrhage.

Fibrosis in incisions was higher in the vacuum groups (Groups I/II/III/IV: 80/60/100/100%; P = .016). The necrosis rate was lower in Groups III and IV (Groups I/II/III/IV: 80/100/42.9/28.6%; P = .006). However, Groups III and IV were associated with a higher risk for moderate/severe gastritis (Groups I/II/III/IV: 10/0/100/100%; P < .001) and mucosal erosion (Groups I/II/III/IV: 0/0/100/85.7%; P < .001). The gastritis was more intense in Group IV than in Group III (P < .001). No significant differences were found for adhesions and angiogenesis (P > .05). The overall healing score was higher for Groups III and IV (median score for Groups I/II/III/IV: 0.5/2/3/4; P = .019), and this score did not differ between Groups III and IV (P = .502).

Vacuum therapy acts on the initial phases of the healing process, reducing necrosis and increasing fibrosis. Intense negative pressure is associated with severe gastritis and mucosal erosion.