Effect of antioxidant therapy on collagen synthesis in corrosive esophageal burns

To investigate the efficacy of antioxidant therapy on collagen synthesis in corrosive esophageal burns, 110 Sprague-Dawley rats were divided into five groups of 22 animals each. A standard esophageal caustic burn was produced by 1 ml of 10% sodium hydroxide solution for the rats in groups B to E; group A was instilled only with 0.9% saline after preparation of the distal esophageal segment. Group A animals (controls) were uninjured and untreated. Group B had untreated esophageal burns. Esophageal burns were treated in group C with vitamin E (10 mg/kg IM), in group D with vitamin C (10 mg/kg IP), and in group E with methylprednisolone (30 mg/kg IM) on each of 5 days. Eight rats from each group were killed 4 days after initiation of the study and the abdominal esophagus was studied for tissue malondialdehyde (MDA; micromol/g protein) levels. The other rats were killed 28 days after initiation of the study and determination of hydroxyproline (HP) (microg/g tissue) levels in esophageal tissue was performed for 8 rats in each group. Histopathologic evaluation was also performed in the other 6 rats from each group. MDA levels in esophageal tissue were significantly lower in groups C (9.24 +/- 2.62, P < 0.01) and group E (6.26 +/- 2.22, P < 0.001) than in group B (12.35 +/- 1.80). HP levels were significantly lower in groups A (0.75 +/- 0.21, P < 0.001), C (1.11 +/- 0.15, P < 0.01), and E (0.96 +/- 0.15, P < 0.001) than in group B (1.40 +/- 0.20). Histopathologically, collagen deposition in the submucosa and tunica muscularis was lower in groups C and E than in group B (P < 0.05, and 0.01, respectively). Our results demonstrate that treatment with antioxidant drugs such as vitamin E and methylprednisolone decreased tissue HP levels, and thus inhibited new collagen synthesis and stricture formation in rats with alkali-induced caustic esophageal burns.