The preventive effect of heparin on stricture formation after caustic esophageal burns

Background/Purpose: Preventing thrombus formation after caustic esophageal ingestion has been proposed to have beneficial effects. Therefore, an exper imental study was carried out to investigate the effects of heparin on the esophagus after caustic burns. Methods: Caustic esophageal burns were produced in rats by irrigation with 50% NaOH as described by Liu. Rats were divided into four groups as follows : group A, animals with esophageal burns, received placebo and underwent au topsy 48 hours after caustic injury; group B, animals with esophageal burns , received subcutaneous heparin treatment and underwent autopsy 48 hours af ter caustic injury; group C, animals with esophageal burns, received placeb o and underwent autopsy 28 days after caustic injury; group D, animals with esophageal burns, received subcutaneous heparin treatment for 7 days and u nderwent autopsy 28 days after caustic injury. Histopathologic evaluation w as performed in all groups, and collagen content of esophageal sections was analyzed by determination of hydroxyproline levels. Results: Submucosal vascular thrombosis was encountered in all group A anim als but the submucosal venules and arterioles were patent in most of group B animals. Esophageal strictures did not develop in any of group D animals, although varying degree of esophageal stenoses were encountered in all ani mals of group C. The circumferences of the burned segment have been narrowe d to 3 +/- 1 mm in group C rats. There was obvious collagen deposition in s ubmucosa, and epithelial regeneration was not complete in group C rats. Sub mucosa and epithelial integrity seemed normal in group D animals. Hydroxypr oline contents in group D were significantly lower compared with group C (P <.05). Conclusions: Heparin has ameliorating effects on stricture formation after caustic esophageal burn. Those effects may occur through possible anticoagu lant, antithrombotic, and endothelial protective effects, and modifying eff ects of heparin on wound healing.