Effect of polaprezinc on experimental corrosive esophageal burns in rats.

Unconsciously caustic ingestion is one of the most common causes of serious esophageal strictures in children. The aim of this study is to determine the efficiency of polaprezinc in preventing stricture formation after corrosive esophageal burns (CEB); this was the first time it has been used to treat experimental CEB in rats. Twenty-four rats were divided into four groups, three of which received CEB by the instillation of 1 mL of 10% NaOH solution into their isolated esophageal segments for three minutes. Group C (control) was uninjured and untreated. Group B (esophageal burn) received CEB but were left untreated. Groups PT1 and PT2 had CEB and received 100 mg/kg/day and 200 mg/kg/day, respectively, of intraperitoneal polaprezinc treatment (PT) for the first two weeks, then oral PT for another two weeks. We assessed the treatment's efficiency of the treatment after the fourth week by evaluating the stenosis index (SI) and the histopathological damage score, determining tissue hydroxyproline content (HP), and measuring the weight of the rats before and after the experiment. Mean SI was statistically lower in the groups PT1 and PT2 when compared with Group B (p = 0.006, 0.004, respectively). HP levels were highest in Group B, but it was insignificant (P> 0.05). In terms of histopathological damage score, treatment groups demonstrated less collagen deposition, mucosal, and submucosal damage than both Group B (p = 0.01) and Group C (p = 0.02). Group PT1 and Group PT2 (P> 0.05) showed similar results, indicating the treatment's effectiveness was independent of dosage. Outside of Group C, weight gain was detected only in Group PT2, though it was statistically insignificant. In Group PT1, weight loss was lower than in Group B. Polaprezinc, with its antifibrotic, antioxidant, anti-inflammatory, wound-healing and antiapoptotic effects, was efficient in reducing stricture formation by decreasing HP levels and histopathologic damage, preventing stenosis, and weight gain in higher dosages in the treatment group.

Rat tail revascularization model for advanced microsurgery training and research.

We describe a time-saving microsurgical exercise for continuing microsurgical training and research. The rat tail replantation model was simplified by excluding bone detachment. Rats were divided into two groups: devascularization only ( N = 3) and revascularization after devascularization ( N = 7). The tail was devascularized by ligation and division of artery and veins in the first group to reveal if a collateral circulation from bone existed. The divided vessels were reanastomosed in the second group. The circulation of the rat tails was followed for 1 week. The tails showed total necrosis in the devascularization group, whereas only two of seven tails showed partial necrosis in the revascularization group. Reexploration showed thrombosis narrowing the lumen at the anastomotic site of the partially necrosed tails, most likely due to an anastomotic insufficiency. The present study revealed that total amputation is not necessary for tail devascularization. The rat tail revascularization model provides a practical tool for advanced and continuing microsurgical training and research.

Effect of stent placement, balloon or cutting balloon dilatation on stricture formation after caustic esophageal burn in rats.

INTRODUCTION: This study aimed to evaluate the effects of stent placement prior to stricture development following caustic esophageal burn (CEB) in an animal model. The outcomes after stent placement were also compared with those after balloon dilatation and cutting balloon dilatation performed after stricture development. Groups were compared with regard to stricture development and weight loss. MATERIALS AND METHODS: 40 rats were divided into 5 groups. CEB was created as described by Gehanno et al. In Group A (control) no CEB was performed and the esophagus was only rinsed with saline. Group B rats underwent CEB with no subsequent treatment. Group C rats underwent CEB followed by balloon dilatation in the 3 (rd) and 4 (th) week. Group D rats underwent CEB followed by cutting balloon dilatation in the 3 (rd) week. Group E rats underwent CEB with subsequent placement of a silicon stent in the same session. The animals were sacrificed in the 6 (th) week, and the stenosis index (SI), collagen deposition, and hydroxyproline (HP) levels were determined in the esophageal segments and statistically compared. RESULTS: Although weight loss occurred in Group C and Group B rats (238.87±15.95 g vs. 233.83±19.01 g), weight loss in Group C rats was less marked compared to Group B. Similarly, the SI in Group C was lower compared to that of Group B and the difference was statistically significant. Although there was no difference in weight between the rats in Group C and Group B before the procedure (p=0.318), there was statistically significant difference thereafter (p=0.002). The SI of Group D was also lower compared with that of Group B, and the difference was statistically significant. Weight gain in Group E rats was similar to that noted in Group A rats and was higher compared to Group B; this difference was statistically significant. The SI for Group E was lower compared to that of Group B. CONCLUSION: Stenting performed at the time of corrosive injury and cutting balloon dilatation performed after stricture formation had a positive effect with regard to SI and weight gain in an animal model.