Photothermal-mediated Local Heating Using Nano-functionalized Stent to Treat Stent-induced Tissue Hyperplasia in Rat Esophagus

Abstract

Background and Purpose: The aim of the present study was to investigate the effectiveness of photothermal therapy (PTT) using a gold nanoparticle (AuNP)-coated stent for treating stent-induced tissue hyperplasia in the rat esophagus.

Materials and Methods: All experiments were approved by animal research committee. An AuNP-coated, self-expandable metallic stent (SEMS) was produced to conduct PTT under near-infrared laser irradiation. Forty rats were randomly divided into four groups (10 rats each). The animals in group A (non-coated SEMS) and group B (AuNP-coated SEMS with local heating at 65°C at 4 weeks) were sacrificed 4 weeks after stent placement. The rats in group C (AuNP-coated SEMS with local heating at 65°C at 4 weeks) and group D (AuNP-coated SEMS with local heating at 65°C at 4 and 8 weeks, respectively) were sacrificed 8 weeks after stent placement. The effectiveness of local heating was assessed by histopathological analysis results.

Results: All procedures were successful in all of the animals. Seven rats were excluded because of stent migration (n = 2) and death (n = 5). Tissue hyperplasia-related variables were significantly higher in group A than in groups B-D (all p < 0.05). HSP70 and TUNEL expression were significantly lower in group A than in groups B-D (all p < 0.05). Tissue hyperplasia -related variables were significantly higher in group C than in groups B and D (all p < 0.05).

Conclusion: PTT using AuNP-coated SEMS successfully treated tissue hyperplasia after stent placement in the rat esophagus.

Key words: Self-expandable metallic stent, Photothermal therapy, Gold nanoparticle, Tissue hyperplasia