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

A Novel Rat Model to Simulate the Benign Esophageal Stricture Induced by Endoscopic Submucosal Dissection

Objective

This study aimed to establish a rat model that simulates benign esophageal strictures induced by endoscopic submucosal dissection (ESD).

Materials and Methods

Sixteen male Sprague-Dawley rats were randomly divided into mucosal resection (n = 8) and sham-operated groups (n = 8). The rats in the mucosal resection group underwent a 5-mm three-fourths mucosal resection by way of a 3-mm incision in the distal esophagus under direct visualization via laparotomy. Rats in the sham-operated group underwent a 3-mm incision of the muscularis propria layer in the distal esophagus via laparotomy without mucosal resection. Dysphagia score, weight gain, mucosal constriction rate, and histology were evaluated 2 weeks after surgery.

Results

Technical success was achieved in all the animals. One rat in the mucosal resection group died of infection, and no other complications were observed. Weight gain (P < 0.001) and luminal diameter derived from the esophagograms (P < 0.001) were significantly lower in the mucosal resection group than those in the sham-operated group. Dysphagia score (P < 0.001) and mucosal constriction rate (P < 0.001) were significantly higher in the mucosal resection group than those in the sham-operated group. The inflammation grade (P = 0.002), damage to the muscularis propria (P < 0.001), number of nascent microvessels (P = 0.006), and degree of α-SMA positive deposition (P = 0.006) were significantly higher in the mucosal resection group.

Conclusion

A rat model of benign esophageal stricture induced by ESD was successfully and safely established by mucosal resection.

Paclitaxel-coated balloon catheter for benign esophageal stenosis in a rabbit model

Most patients with benign esophageal stenosis require multiple or even continuous balloon dilation treatments to achieve symptom relief. In this study, eighteen rabbits were used to establish an esophageal benign stenosis model and were divided into a control group (n = 6), a balloon group (n = 6) and a PTX-coated balloon group (n = 6) to evaluate the feasibility and effectiveness of paclitaxel (PTX)-coated balloons for the rabbit esophageal benign stenosis model. The weight and esophageal diameter were recorded every 2 weeks until 8 weeks post-surgery. Hematoxylin-eosin staining, Masson's trichrome staining and immunohistochemical staining were performed for pathological analysis. Four weeks post-operation, there was a significant difference in weight between the control group and the balloon group (p = 0.01) and between the control group and the PTX balloon group (p = 0.01). There was a significant difference in the esophageal diameter between the balloon group and the PTX balloon group at 8 weeks post-operation (p = 0.02). Four weeks post-operation, the degree of inflammatory cell infiltration in the PTX balloon group was significantly lower than that in the control group (p = 0.002) and balloon group (p = 0.001). The degree of collagen deposition in the PTX balloon group was significantly lower than that in the control group (p = 0.002) and balloon group (p = 0.03). Eight weeks post-operation, the percentage of cells positive for TGF-β (p < 0.001), the degree of inflammatory cell infiltration (p = 0.02) and the degree of collagen deposition (p = 0.02) in the PTX balloon group were significantly lower than those in the balloon group. Therefore, PTX-coated balloons may alleviate the local inflammatory response and collagen deposition when used during dilation treatment of benign esophageal stenosis.

Effects of topical application of platelet-rich plasma on esophageal stricture and oxidative stress after caustic burn in rats: Is autologous treatment possible?

BACKGROUND

Caustic esophageal burn is still an important health problem in pediatric surgery. Although there are a number of experimental and clinical studies to increase the recovery of the esophagus and reduce the stenosis rate, there is no consensus on the treatment protocol. Platelet-rich plasma (PRP) is an autologous blood product, which has positive effects on wound healing, reepithelization and scar prevention. The aim of our study was to investigate the effects of PRP on stricture formation and oxidative status after caustic esophageal injury in rats.

METHODS

Twenty-one rats were divided into three groups [Sham operation (n = 8), corrosive esophageal burn with 30% NaOH (n = 6), topical PRP application after corrosive burn (n = 7)]. On the postoperative 21st day, oxidative markers were measured in the serum, and collagen accumulation and stenosis index were measured histopathologically to assess the efficacy of PRP treatment.

RESULTS

Postoperative weight was higher than preoperative weight in Sham and PRP groups, but lower in the Burn group (p < 0.05). No difference was observed between Sham and PRP groups at total antioxidant status and paraoxonase values, but a significant decrease was found in the Burn group. Group PRP had higher total oxidant status and arylesterase levels than Group Burn (p < 0.05). There was no difference in total thiol values between PRP and Sham group. Histopathological scoring for muscularis mucosa damage revealed a significant reduction in Group PRP, compared to Group Burn (p < 0.05). Esophageal wall thickness and SI were reduced, and luminal diameter was increased in Group PRP compared to Group Burn (p < 0.05).

CONCLUSION

For the first time in the literature, these results indicate that topical PRP treatment after the experimental corrosive burn has a positive effect on oxidative stress, mucosal healing and decreased stricture development. PRP may be an alternative at the clinical treatment because it can be used during diagnostic esophagoscopy.

TYPE OF STUDY

Treatment study Level I (randomized controlled trial).

The effect of platelet-rich plasma on motility changes in experimental caustic esophageal burn

BACKGROUND

Besides stricture formation, diminished esophageal motility after caustic esophageal burns also plays a role in the deterioration of the clinical course. In this study, we aimed to investigate the effect of caustic burn on the esophageal contractions and the effect of platelet-rich plasma (PRP) on these changes.

METHODS

Twenty-one Wistar albino rats were divided into three groups [Sham operation (n = 8), caustic esophageal burn with NaOH (n = 6), PRP treatment after caustic burn (n = 7)]. After 3 weeks, esophagectomy was performed and contractions and EFS responses were evaluated in the organ bath.

RESULTS

KCl- and acetylcholine-induced responses were reduced in the Burn group, but increased in Sham and PRP groups (p < 0.05). EFS responses were higher in Burn group compared to the other groups. Response with L-arginine was increased in Burn group, but decreased in PRP group. There was more decrease in the contraction in Sham and PRP groups compared to the Burn group after SNP (sodium nitroprusside) incubation (p < 0.05). L-NAME (Nω-Nitro-L-arginine methyl ester) did not change the EFS responses in the Burn group, but EFS responses were decreased significantly in Sham and PRP groups (p < 0.05). EFS responses were decreased in all groups, but more in the Sham and PRP groups after Y-27632 (Rho-kinase inhibitor) incubation (p < 0.05).

CONCLUSIONS

For the first time, we demonstrated that both cholinergic and non-adrenergic non-cholinergic mechanisms are responsible for the altered motility in corrosive esophageal injury. Our results suggest that PRP treatment may be helpful in regulating the esophageal motility and decreasing altered contractions in corrosive burns. This effect may also contribute to the reduction of stricture formation, especially by reducing inappropriate contractions of the esophageal wall during the post-burn healing phase.

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.

Topical application of basic fibroblast growth factor reduces esophageal stricture and esophageal neural damage after sodium hydroxide-induced esophagitis in rats

PURPOSE

To investigate the effect of topical application of basic fibroblast growth factor (bFGF) after caustic esophageal injury in rats.

METHODS

Thirty-six male rats were randomly divided into three groups. Corrosive esophageal injury was produced by internal application of 30% sodium hydroxide (NaOH) solution to the distal esophagus. Group A rats were uninjured. Group B rats were injured and untreated. Group C rats were injured and received topical bFGF (10 μg/ml). Surviving rats were killed at 28 days. The survival rate, body weight gain, symptoms and histopathological changes that included tissue damage score, ratio of esophageal luminal area/total esophageal area (LA/TA) and the proportion of a neural marker PGP 9.5-positive area were assessed.

RESULTS

The survival rate and the prevalence of symptoms were not significantly different between Groups B and C. Although the tissue damage score did not differ in Groups B and C, LA/TA was significantly higher in Group C than in Group B. The proportion of the PGP 9.5-positive area was significantly lower in Groups B and C than in Group A; however, it was higher in Group C than in Group B.

CONCLUSION

Topical application of bFGF was effective in preventing stricture after NaOH-induced esophagitis.