Objective To evaluate the efficacy and safety of a novel gastrointestinal mucosal elevation gel in vivo porcine model.

Methods Eight healthy white pigs were selected, which were divided into bump height evaluation (n=2) and safety evaluation (n=6). The sample (alimentary canal mucosa bump gel sample) and the control sample (disposable endoscopic submucosal filler of alimentary canal) were respectively injected into the submucosa of pig gastric antrum and gastric body. In the evaluation of elevation height, the morphology, persistence, and clinical safety of mucosal elevation were observed and recorded immediately and 30 minutes after injection. In safety evaluation, endoscopic mucosal resection was performed after injection, and the mucosal protrusion shape, product efficacy, and clinical safety were observed and recorded at immediate and 7-day time points. After observation, all animals were euthanized and tissue samples were collected and excised for histopathological evaluation.

Results In elevation height evaluation, sample group showed a steep elevation immediately after surgery, exhibiting a more pronounced elevation morphology compared to control group (P=0.019). Only two(25%) sites of the elevation showed slight collapse in 30 minutes after surgery, and the durability notably increased compared to control group (8 all collapsed, P＜0.001). In safety evaluation, the average trauma area of sample group was 1.77 mm², which was significantly lower than control group (2.65 mm², P＜0.001). There was no statistical difference among average injection dose per unit area, surgical time per unit area, and en bloc resection rate. Sample groupt showed mild ulcers and only 1 (12.5%) site of mild bleeding at immediate time point after surgery. No bleeding, perforation, ulcer or edema was observed in sample group 7 days after surgery, and no statistical difference was identified compared to control group. Histopathological evaluation found that the gastric antrum and body tissues exhibited moderate injury and mild edema at immediate time point, accompanied by mild inflammatory cellular infiltration. At 7d time point, gastric antrum tissues demonstrated moderate injury, mild edema and mild inflammatory cellular infiltration, with 1 (12.5%) site of tissues infected, while in gastric body tissues, no bleeding was observed, whereas moderate injury and mild edema were evident, accompanied by mild inflammatory cellular infiltration and 3 (37.5%) sites of tissues infected, all of which were not statistically different from control group.

Conclusion The novel gastrointestinal mucosal elevation gel exhibited steep elevation morphology, long-lasting elevation height, and favorable efficacy and safety in preclinical animal trials, showing enormous clinical application potential.