New experimental corrosive esophagitis model in rats

Evaluation of effects of curcumin on acute esophagitis in the corrosive esophagitis model in rats

Ingestion of a corrosive substance may cause corrosive esophagitis. Curcumin has anti-inflammatory and mucosal protective effects. In this study, the effects of curcumin on the acute phase of corrosive esophagitis were investigated. Twenty-seven Wistar Albino rats were divided into four groups; sham (group I), control (group II), and experiment groups (group III, 100 mg/kg curcumin; group IV, 200 mg/kg curcumin). Forty percent sodium hydroxide solution was used to erode the esophagi of rats in groups other than the sham group. Curcumin was applied to animals in the experiment groups 10 min after the corrosion. After 24 h, animals were sacrificed, and esophagus samples were collected. According to the histopathological examination, the muscularis mucosa damage was regressed from 100% in group II to 71.4% in group III and 50% in group IV. Mild level of damage and collagen deposition in the tunica muscularis regressed from 66.7% of the animals in the control group to 42.9% in group III and to none in group IV. Further, an increase in submucosal collagen was present in all samples from groups II and III, while 83.3% of samples had an increase in submucosal collagen in group IV. There was a significant difference in the histopathological total score between the control group and group IV (p=0.02). The results showed that the administration of curcumin in a dose-dependent manner can relieve the acute phase of corrosive esophagitis.

Prevention of esophageal stenosis via in situ cross-linkable alginate/gelatin powder in a new submucosal exfoliation model in rats

Endoscopic submucosal dissection (ESD) for the treatment of esophageal mucosal lesions often leads to postoperative stenosis, causing difficulty in swallowing, known as dysphagia. In this study, we developed an in situ cross-linkable powder composed of alginate, gelatin, transglutaminase (TG), and calcium chloride ions (Ca2+), which can be administered through a 1.5 m-long and 3.2 mm-diameter endoscopic instrument channel. The powdered mixture of alginate and gelatin quickly formed a hydrogel by absorbing body fluids and was cross-linked by TG and Ca2+, which adhered ex vivo to porcine submucosal layers for over 2 weeks. In addition, we developed a new submucosal exfoliation model in rats that induced severe stenosis, similar to the ESD-induced stenosis models in clinical practice. When administered to the new rat model, the powder system effectively reduced the severity of esophageal stenosis based on body weight change monitoring, anatomical findings, and histological analysis. The body weight of the rats was maintained at the initial weight on postoperative day 14 (POD14), and epithelialization on POD7 and 14 improved to almost 100%. Additionally, collagen accumulation and the number of α-SMA-positive cells decreased due to powder administration. Therefore, these findings indicate that the in situ cross-linkable powder can prevent esophageal stenosis after ESD.

Severe Intentional Corrosive (Nitric Acid) Acute Poisoning: A Case Report and Literature Review

Despite being one of the most debilitating conditions encountered in the field of toxicology, there is a lack of neutralization measures for the toxins involved in acute corrosive poisoning, and this promotes progressive contact injury of deep tissues after poisoning has occurred. Multiple controversies still surround management strategies during the acute phase of poisoning and the long-term follow-up of the patient. Here, we report a severe case of intentional poisoning with nitric acid complicated by extensive injury of the upper digestive tract, multiple stricture formation, and complete dysphagia. Serial endoscopic dilation and insertion of a jejunostomy feeding tube were necessary, and underlying psychiatric illness negatively affected the outcome of the patient. We conclude that an interdisciplinary approach is necessary to properly reduce the extent of lesions and sequelae induced by corrosion. Early endoscopic mapping of injuries is of major importance to better predict the evolution and possible complications of poisoning. Interventional and reconstructive surgical procedures may significantly improve the life expectancy and quality of life of patients following intoxication with corrosive substances.

Effectiveness of Hypericum perforatum Extract in the Treatment of Corrosive Esophageal Burns

PURPOSE

The purpose of our study is to determine the effectiveness of "Hypericum perforatum" extract in corrosive esophageal burns and to shed light on the search for new treatments.

MATERIALS AND METHODS

A total of 32 Sprague Dawley rats were separated into 4 groups. A standard esophageal burn model was created. Group 1 was identified as the sham group. Group 2 was burned and no treatment was performed afterward. Group 3 was burned and then 2 cc/day H. perforatum extract was given for 21 days. Group 4 was not applied any process and 2 cc/day H. perforatum extract was given for 21 days. The rats were sacrificed and biopsy specimens were taken for histopathological examination for the presence of inflammation, fibrosis, and necrosis.

RESULTS

There was a significant difference between groups in terms of inflammation, fibrosis, and necrosis. Furthermore, in the bilateral comparisons between the groups, there was a meaningful difference in terms of inflammation and fibrosis between Group 2 and Group 3. However, there was no meaningful difference between the same groups in terms of necrosis.

CONCLUSION

H. perforatum extract may be effective on inflammation, fibrosis, and necrosis in corrosive esophageal burns.

Effects of Carvacrol in an Experimentally Induced Esophageal Burn Model: Expression of VEGF and Caspase-3 Proteins

INTRODUCTION

We investigated the therapeutic effects of carvacrol in an experimental esophageal burn rat model with immunohistochemical techniques. Materials and Methods: Three groups were included in this study, composed of eight Wistar albino rats each. The control group was given 1 mL 0.9% (wt/vol) NaCl; esophageal burns were induced in groups 2 and 3 by administration of 1 mL 40% NaOH in the distal 2 cm of the esophagus. The treatment group was administered 75 mg/kg carvacrol in 2 mL 0.9% NaCl for 10 days. After a routine histological examination of the tissues, sections were stained with vascular endothelial growth factor (VEGF) and caspase-3 for immunohistochemical analysis and were examined under a light microscope. Results: In the control group, there were regular cells in the cornified epithelial tissue and cylindrical cells in the basal layer, which faced toward the apical surface in the mitotic phase. The burn group displayed wide degeneration, necrosis, and abundant apoptotic cells in the epithelial tissue as well as intense inflammatory cell infiltration. In the treatment group, there was an increase in mitotic activity in the basal cells of the epithelial layer and degenerative changes, but a preserved epithelial layer and significant cornified structures. The treatment group showed positive caspase-3 expression in some apoptotic cells within the epithelial layer and in connective tissue, and there were only a small number of degenerated cells in the muscle layer. Additionally, in the treatment group, VEGF expression was evident in small numbers of inflammatory cells in the papillary region of the epithelium, and in dilated vascular endothelial cells. Conclusions: Carvacrol may contribute to a reduction in fibrosis by decreasing inflammation and preventing cell apoptosis.

Bilayer silk fibroin grafts support functional oesophageal repair in a rodent model of caustic injury

Surgical repair of caustic oesophageal injuries with autologous gastrointestinal segments is often associated with dysmotility, dysphagia and donor site morbidity, and therefore alternative graft options are needed. Bilayer silk fibroin (BLSF) scaffolds were assessed for their ability to support functional restoration of damaged oesophageal tissues in a rat model of onlay oesophagoplasty. Transient exposure of isolated oesophageal segments with 40% NaOH led to corrosive oesophagitis and a 91% reduction in the luminal cross-sectional area of damaged sites. Oesophageal repair with BLSF matrices was performed in injured rats (n = 27) as well as a nondiseased cohort (n = 12) for up to 2 months after implantation. Both implant groups exhibited >80% survival rates, displayed similar degrees of weight gain, and were capable of solid food consumption following a 3-day liquid diet. End-point μ-computed tomography of repaired sites demonstrated a 4.5-fold increase in luminal cross-sectional area over baseline injury levels. Reconstructed oesophageal conduits from damaged and nondiseased animals produced comparable contractile responses to KCl and electric field stimulation while isoproterenol generated similar tissue relaxation responses. Histological and immunohistochemical evaluations of neotissues from both implant groups showed formation of a stratified, squamous epithelium with robust cytokeratin expression as well as skeletal and smooth muscle layers positive for contractile protein expression. In addition, synaptophysin positive neuronal junctions and vessels lined with CD31 positive endothelial cells were also observed at graft sites in each setting. These results provide preclinical validation for the use of BLSF scaffolds in reconstructive strategies for oesophageal repair following caustic injury.

A corrosive oesophageal burn model in rats: Double-lumen central venous catheter usage

BACKGROUND

We aimed to create a new and less invasive experimental corrosive oesophageal burn model using a catheter without a gastric puncture (gastrotomy).

MATERIALS AND METHODS

We conducted the study with two groups composed of 8 male rats. The experimental oesophageal burn was established by the application of 10% sodium hydroxide to the distal oesophagus under a pressure of 20 cmH 2 O, via 5-F double-lumen central venous catheter without a gastrotomy. The control group was given 0.9% sodium chloride. All rats were killed 24 h after administration of NaOH or 0.9% NaCl. Histologic damage to oesophageal tissue was scored by a single pathologist blind to groups.

RESULTS

The rats in the control group were observed to have no pathological changes. Corrosive oesophagitis (tissue congestion, oedema, inflammation, ulcer and necrosis) was observed in rats exposed to NaOH.

CONCLUSION

We believe that an experimental corrosive oesophageal burn can safely be created under same hydrostatic pressure without a gastric puncture using this model.

A novel model approach for esophageal burns in rats

Background:

Corrosive esophageal injury causes serious clinical problems. We aimed to create a new experimental esophageal burn model using a single catheter without a surgical procedure.

Materials and methods:

We conducted the study with two groups of 12 male rats that fasted for 12 h before application. A modified Foley balloon catheter was inserted into the esophageal lumen. The control group was given 0.9% sodium chloride, while the experimental group was given 37.5% sodium hydroxide with the other part of the catheter. After 60s, esophagus was washed with distilled water. The killed rats were examined using histopathological methods after 28 days.

Results:

In comparison with the histopathological changes experienced by the study groups, the control groups were observed to have no pathological changes. Basal cell degeneration, dermal edema, and a slight increase in the keratin layer and collagen density of submucosa due to stenosis were all observed in the group subjected to esophageal corrosion.

Conclusion:

A new burn model can thus, we believe, be created without the involvement of invasive laparoscopic surgery and general anesthesia. The burn in our experiment was formed in both the distal and proximal esophagus, as in other models; it can also be formed optionally in the entire esophagus.

Comparison of mitomycin-c and heparin affects in experimental corrosive esophagitis on rats

OBJECTIVE

We comparative effects of mitomycin-c and heparin which have different mechanism of action in a minimal invasive corrosive esophagitis model which was formed by NaOH 40%.

METHOD

The study was performed on forty female Wistar albino rats; were divided into four equal groups each including ten animals. Group C (n=10); control, the group that esophagus was washed with normal saline, group I (n=10); injury group; alkali esophagus burn, not treated, group M (n=10); alkali esophagus burn, mitomycin-c treatment group, group H (n=10); alkali esophagus burn, heparin treatment group. The study was performed on a minimal invasive model which did not require general anesthesia and abdominal operation. In 28 day, all subjects were killed and their esophagus's were removed by thoraco-abdominal cut. Total esophagi from oropharynx to stomach were removed and they were examined macroscopically and microscopically and evaluated for esophageal tissue collagen deposition and histopathologic damage score.

RESULTS

When group C is compared with each of the other groups, statistically significant weight losses were detected; [(p<0.005, p<0.05, p<0.005), respectively]. Significant inflammation increase was detected in groups I, M and H in comparison to group C [(p<0.001, p<0, 0001, p<0.005)]. When granulation scores of groups were compared; statistically significant granulation increases were detected in groups I, M, and H [(p<0.05, p<0.05, p<0.05) compared to group C]. Significant collagen increase was detected in all 3 layers in groups; I, M and H according to group C [(p<0.05, p<0.05, p<0.05)]. Collagen increase in every 3 layers in groups M and H were significantly less according to group I [(p<0.05, p<0.05, p<0.05)]. Collagen increase in every 3 layers was less in group M than group H (p<0.05).

CONCLUSION

In corrosive esophagitis due to NaOH, heparin treatment is more effective in inflammation and granulation formation, mitomycin-c treatment is more effective in preventing the collagen accumulation step. Heparin decreases the tissue damage by preventing the inflammation and granulation formation; and prevents collagen accumulation and stricture development. As completing the effect of heparin; mitomycin prevents fibroblastic activity inhibition with direct collagen accumulation and stricture development strongly.

Development of a model of benign esophageal stricture in rats: the optimal concentration of sodium hydroxide for stricture formation

PURPOSE

To investigate the optimal concentration of sodium hydroxide (NaOH) on esophageal stricture formation in rats to establish an animal model of benign esophageal stricture (BES).

METHODS

Corrosive esophageal burn was produced by internal application of different concentrations of NaOH to the distal esophagus in rats. As much as 66 male rats were randomly divided into eight groups: Group A (control, n = 6), Group B (sham-operated group, n = 6), Group C (5% NaOH, n = 8), Group D (10% NaOH, n = 8), Group E (20% NaOH, n = 8), Group F (30% NaOH, n = 10), Group G (40% NaOH, n = 14), and Group H (50% NaOH, n = 6). Surviving rats were killed at 28 days. The survival rate, body weight gain, symptoms, and histopathological changes were assessed.

RESULTS

The mortality rate was high in Groups G and H (73 and 67%). The prevalence of symptoms of BES was 43% in Groups D and E, 50% in Group F, 75% in Group G, and 100% in Group H. Statistically significant stricture formation of the esophagus was observed in Groups F and G. The degree of tissue damage was significantly higher in Groups E, F, and G.

CONCLUSION

A high concentration of NaOH of 30% was required to establish a survivable BES model in rats.