Evaluation of the relation between interstitial cells of cajal (CD117) and serotonin receptor (5HT-3A) with postfundoplication dysphagia

Distribution of interstitial cells of Cajal in the Esophagus and change in distribution after thoracic trauma

Interstitial cells of Cajal (ICCs) function as pacemaker cells in the gastrointestinal tract. Acute thoracic trauma is a common and lethal cause of death due to physical trauma caused by traffic accidents. This study aimed to explore the distribution of esophageal ICCs and distribution changes observed after acute thoracic trauma. Thirty rabbits were randomly divided into a control group and two study groups. The control group animals underwent an esophagectomy. All animals in the study groups underwent right chest puncture using the Hopkinson bar technique. The study groups were subjected to esophagectomy 24 and 72 h after chest puncture. Distribution, morphology, and density of esophageal ICCs were detected using transmission electron microscopy, toluidine blue staining, and immunohistochemistry. Apoptosis of esophageal ICCs was evaluated using the terminal deoxynucleotidyl transferase (TdT) dUTP Nick-End Labeling assay. Western blotting and reverse transcription polymerase chain reaction were used to detect changes in the SCF/c-kit signaling pathway. Esophageal ICCs distribution and SCF/c-kit signal pathway decreased from the upper part to the lower part in both physiological state and after thoracic trauma. In contrast, death of ICCs increased from the upper part to the lower part, both in physiological and injured state (P < 0.05). After thoracic trauma, increased ICCs and decreased death of ICCs in all parts of the esophagus (P < 0.05) were observed. The observed distribution and changes in esophageal ICCs would have an impact on motility and motility disorders of the esophagus.

Changes in esophagus interstitial cells of Cajal in response to acute stress

BACKGROUND

Thoracic trauma is common, and traffic accident-related traumatic injury can cause acute stress leading to esophageal motility disorders. Interstitial cells of Cajal (ICCs) are regarded as gastrointestinal pacemaker cells.

AIM

This study explored the mechanism underlying changes in lower esophagus ICCs under acute stress conditions.

METHODS

Fifty adult rabbits, randomly divided into one healthy control and four study groups, were subjected to right chest puncture using a Hopkinson bar. Thereafter, one group was immediately subjected to lower esophagectomy, whereas the other three groups were maintained for 24, 48 and 72 h after puncture and subjected to lower esophagectomy. Immunohistochemistry was used to detect ICC distribution, morphology and density, and TUNEL assays were used to determine ICC apoptosis. Enzyme-linked immunosorbent assays (ELISAs) were used to measure cortisol, epinephrine, dopamine, IL-9, cholecystokinin (CCK) and vasoactive intestinal peptide (VIP). Western blotting and RT-PCR were performed to detect changes in SCF/c-kit and nNOS pathways.

RESULTS

After puncture, lung tissue was hemorrhaged, alveoli in puncture areas were destroyed, esophageal pH was decreased, and serum cortisol, epinephrine and dopamine levels increased. ICC numbers increased and apoptotic ICCs decreased in all stress groups after puncture (all p < .01). IL-9, CCK and VIP levels in lower esophagus tissue were increased after puncture (all p < .01). Moreover, SCF/c-kit and nNOS pathways were upregulated in response to stress (all p < .01).

CONCLUSIONS

Acute stress promotes increases in lower esophageal ICCs that might affect esophagus ICC functions and esophageal motility.

Effects of sacral nerve electrical stimulation on 5‑HT and 5‑HT3AR/5‑HT4R levels in the colon and sacral cord of acute spinal cord injury rat models

Spinal cord injury (SCI) often leads to defecation dysfunction. Sacral nerve electrical stimulation (SNS) therapy could improve defecation function. The present study aimed to assess SNS therapy, with regard to the levels of serotonin (5-HT) and its receptors (5-HT3AR and 5-HT4R) in the colon and sacral cord, a rat model of acute severe SCI was used. This rat model was made using the New York University Impactor device. Model rats were randomized to the SCI and SNS (electrical stimulation on the S3 nerve) groups. After 14 days of treatment, enteric transmission function was assessed. 5-HT and 5-HT3AR/5-HT4R were measured by ELISA, quantitative PCR, immunohistochemistry and western blotting. In SCI rats, SNS significantly increased the quantity of feces, shortened the time to the first fecal passage, and improved fecal texture and colon histology. SNS elevated 5-HT contents in the colon and spinal cord, and enhanced 5-HT3AR/5-HT4R protein expression and distribution in the colonic myenteric plexus and mucosa, sacral intermediolateral nucleus and dorsal horn. SNS upregulated the relative expression levels of 5-HT3AR/5-HT4R mRNA and protein in the colon and spinal cord. SNS can improve defecation and accelerate the recovery of colonic transmission functions in rat models of acute SCI. These effects involved upregulation of the 5-HT/5-HT3AR/5-HT4R axes.

Modified Liu-Jun-Zi decoction alleviates visceral hypersensitivity in functional dyspepsia by regulating EC cell-5HT3r signaling in duodenum

ETHNOPHARMACOLOGICAL RELEVANCE

Modified Liu-Jun-Zi (MLJZ) is derived from one of the most famous traditional Chinese prescription Liu-Jun-Zi. It exhibits therapeutic effects in functional dyspepsia (FD), but the underlying mechanisms remain not well understood. Enterochromaffin (EC) cells contribute to the pathogeneses of visceral hypersensitivity in functional gastrointestinal disorders. But whether and how EC cells in duodenum participate in the mechanism of FD remain unsettled.

AIM OF THE STUDY

To detect the crucial factors related to EC cells, and to evaluate the therapeutic effect of MLJZ and to determine whether MLJZ relieves visceral hypersensitivity in FD by regulating EC cell-5-hydroxytryptamine 3 receptor (5HT3r) signaling.

MATERIALS AND METHODS

FD rats were established by iodoacetamide gavage combined with tail clamping method. The verification of FD model and the evaluation of the therapeutic effect of MLJZ was taken place by hematoxylin-eosin (HE) staining and visceral sensitivity measurement. The expression of EC cells and 5-hydroxytryptamine (5HT) in duodenum was detected by Immunohistochemistry (IHC) staining and enzyme-linked immunosorbent assay (ELISA). IHC staining and quantitative polymerase chain reaction (qPCR) were applied to measure the expression of tryptophan hydroxylase-1 (TPH1), paired box gene 4 (PAX4), transient receptor potential A1 (TRPA1), transient receptor potential C4 (TRPC4) and 5HT3r. Duodenum sections were stained by double immunofluorescence (IF) to study the synthesis of 5HT in EC cells.

RESULTS

The gastric sensitivity increased in FD rats while MLJZ decoction significantly attenuated visceral hypersensitivity. The duodenum of FD rats displayed increased expressions of EC cells, 5HT, TPH1, PAX4 and 5HT3r. And the overexpression was reduced in response to MLJZ decoction treatment.

CONCLUSIONS

EC cell-5HT3r signaling pathway is abnormally active in FD with visceral hypersensitivity. And MLJZ decoction can alleviates visceral hypersensitivity in FD by regulating EC cell-5HT3r signaling in duodenum.