Proteinase-activated receptor 2 distribution and expression in equine small intestine tracts following herniation through the epiploic foramen.

This research study aimed to investigate how the proteinase-activated receptor 2 (PAR2) is distributed and expressed in the small intestine of horses during herniation through the epiploic foramen.

Study Objective and Methods

• The researchers targeted the proteinase-activated receptor 2 (PAR2), which is a receptor that responds to trypsin and mast cell tryptase. PAR2 is typically found in high concentrations in the intestines, where it performs various functions such as controlling intestinal motility and epithelial permeability.
• This clinical study took a prospective approach and included eight horses who had been admitted for colic and were undergoing exploratory laparotomy.
• During the surgery, samples were taken from the jejunum or the ileum of the horses through a procedure called enterectomy. A variety of analyses were then performed on these resected intestinal samples. These included morphological examinations such as histology and immunohistochemistry of PAR, as well as molecular biology analyses like western blot and quantitative polymerase chain reaction.

Data Analysis and Results

• The researchers defined Marginal Injured Tracts (MITs) and Central Injury Tracts (CITs). MITs are the oral and caudal marginal segments of the resected bowel tract, and CITs are the geometric centre of the intestinal ischaemic lesion length.
• The presence of PAR, as evidenced by immunoreactivity, was most notable in the epithelial cells. The immunoreactivity in the MITs was more significant than that in the CITs.
• The researchers observed that the immune localisations in the MITs were at the cell membrane level, while in CITs, they were in the cytoplasm.
• No statistical difference was found between the MITs and the CITs in terms of the expression of PAR mRNA and protein (44kDa).
• When compared with control animals, the PAR protein content in the intestinal tracts taken from horses with herniation was lower.

Conclusion

• This study thus provided important information about the presence and distribution of PAR2 in the small intestines of horses experiencing herniation through the epiploic foramen. It contributes to the understanding of the role and behavior of PAR2 in different parts of the intestine during herniation events