<i>Bletilla striata</i> Polysaccharide-Based Interpenetrating Network Hydrogel as an Active Barrier to Prevent Postoperative Primary and Recurrent Adhesions

Postoperative adhesions are a common complication following abdominal surgery, for which current preventive strategies demonstrate limited efficacy. To address this, a novel Bletilla striata polysaccharide (BSP)-based interpenetrating network (IPN) hydrogel as an active barrier was developed. This design integrates the pharmacological activity and biocompatibility of BSP with the robust mechanical and antibiofouling properties of poly( N -hydroxyethyl acrylamide) (PHEAA), based on the pathological characteristics of postoperative adhesions. The physical network of BSP and the chemical network of PHEAA were interpenetrated and entangled through hydrogen bonding, forming a stable BSP/PHEAA IPN structure. A specific BSP/PHEAA hydrogel formulation was selected for its optimal mechanical strength, fouling resistance, degradability, and excellent biocompatibility, stability, and hemostatic properties. The efficacy of the hydrogel in preventing both primary and recurrent postoperative adhesions was assessed using rat cecal–abdominal wall abrasion and postadhesiolysis recurrence models, an effect presumably attributable to its combined barrier function and inherent bioactivity. Molecular biology studies confirmed that the BSP/PHEAA hydrogel modulates the balance between M1 and M2 macrophages and alleviates inflammation. Furthermore, it regulated the MMP-9/TIMP-1 balance by suppressing NF-κB p65 expression, thereby inhibiting fibrosis. Thus, this hydrogel demonstrates significant potential as an active barrier for preventing both primary and recurrent adhesions.