Comparison of intra-peritoneal administration of amnion gel and low-level laser therapy in the prevention of postoperative intra-abdominal adhesion formation in rat model

Objectives None of the current methods can consistently prevent post-operative adhesions consistently and completely. Human amniotic membrane, a regenerative and anti-inflammatory bio-scaffold, and low-level laser therapy (LLLT), which is known to reduce oxidative stress and inflammatory markers, are considered as candidates to modulate adhesion formation. This study aimed to compare the effect of LLLT and amnion in preventing intra-abdominal adhesions in the rat model. Materials and methods In this controlled in-vivo interventional study, 40 female albino Wistar rats were selected and randomly divided into four groups using an online randomization tool. All the groups underwent laparotomy and received either intra-peritoneal amnion gel, a single-shot low-level laser irradiation applied intraperitoneally, low-level laser irradiation applied transcutaneously, or intra-peritoneal deionized water (control). After two weeks, another laparotomy was performed, and the adhesion formation was evaluated as the primary outcome both macroscopically using Lauder and Hoffmann ordinal scoring systems and microscopically according to Zühlke adhesion score. Moreover, serum samples were evaluated to determine the level of cytokines that contribute to inflammation as the secondary outcome, including IL-1 and IL-6. Statistical analysis was performed using one-way ANOVA or, when appropriate, the Kruskal-Wallis test, utilizing SPSS version 22. Results According to the Hoffmann criteria, all the treatment groups including amnion gel (P-value < 0.001, 95% CI of difference = 2.62-6.18), single-shot laser (P-value < 0.001, 95% CI of difference = 2.22-5.78) and multi-shot laser (P-value < 0.01, 95% CI of difference = 1.12-4.68) had significantly less adhesion than the control. However, Lauder criterion showed that only amnion group had less adhesion than control (P-value < 0.001, 95% CI of difference = 1.12-3.48). Microscopic evaluation revealed no significant differences between groups. Postoperative inflammatory markers decreased in all intervention groups throughout the study period, except for IL-6 in the amnion group, where the reduction did not reach statistical significance. Conclusion Our results suggest that human amniotic membrane gel and low-level laser therapy may be effective in preventing intra-abdominal adhesion formation and reducing inflammation in this animal model.