Objective      To probe whether retrievable esophageal stent (RES) can be removed successfully 4 months after placement and prevent forming esophageal stricture in dogs with corrosive esophageal burns.       Methods      Twenty-four dogs were randomly divided into control (without esophageal burns)

burn (without treatment for esophageal burns) and treatment group (RES was placed at 2 weeks after esophageal burns and removed 4 months later). The treatment group was further divided into RES Ⅰ(dogs being killed immediately after RES withdrawal) and RES Ⅱ(dogs being killed 2 months after RES removal). Stricture index was measured and microscopic and ultrastructural features were observed in the harvested esophagus. Hydroxyproline quantities by colorimetry

type Ⅰand Ⅲ collagen mRNA expression by in situ hybridization and their protein levels by ELISA were detected in esophageal tissues. The esophageal compliance and biomechanics were also examined in dogs. TGF-β1

Smad3

Smad7 mRNA expression by RT-PCR and their protein levels by Western blotting were investigated.       Results      One dog died of aspiration less than 24 h after esophageal burns in the burn group

and others developed progressive dysphagia since 3 weeks after injury

only one dog survived. No animal deaths in the groups RESⅠand Ⅱ through the experiment. All dogs could intake regular diet following RES replacement and no significant changes was in their weight before and after the experiment. In comparison with the burn group

stricture index

type Ⅰand Ⅲ collagen mRNA and protein levels

and hydroxyproline quantities decreased significantly in the groups RES Ⅰand Ⅱ(P0.05)

while the esophageal compliance and elasticity among the biomechanics improved dramatically; Histopathological study revealed that collagen diameter was thinner and its orientation tended toward regular and parallel pattern; TGF-β1 and Smad3 mRNA and protein levels increased but Smad7 decreased significantly in esophageal tissues in the groups RES Ⅰ and Ⅱ(P0.01).       Conclusion      RES can be extracted successfully and conveniently 4 months after placement and prevent developing esophageal stenosis in dogs with corrosive esophageal burns. The changes of TGF-β1

Smad3 and Smad7 mRNA and protein levels might relate to the preventive role of RES.