Cytoplasmic and nuclear Survivin expression in healthy gastric mucosae of equids: A comparative study between horses, donkeys, and mules.

Overview

• This study investigated the expression of Survivin protein in the gastric mucosa of healthy equids (horses, donkeys, and mules) to understand its localization and potential role in gastric tissue maintenance.
• The research found that Survivin is present mainly in the cytoplasm of gastric mucosal cells, with varying expression patterns across species and gastric tissue types.

Background

• Survivin is a protein involved in regulating apoptosis (programmed cell death) and promoting mitosis (cell division), which are critical for cellular renewal and tissue homeostasis.
• In human and mouse gastric mucosa, Survivin contributes to cytoprotection mechanisms that maintain mucosal integrity, especially in epithelial cells constantly exposed to stress and damage.
• Information about Survivin’s role and expression in the gastric mucosa of equids, such as horses, donkeys, and mules, had been limited prior to this study.

Objectives

• To determine the expression patterns of Survivin protein—specifically in the cytoplasmic and nuclear compartments—in the gastric mucosa of healthy equids.
• To compare Survivin expression between different equid species (horses, donkeys, mules) and between two types of gastric mucosa: glandular and squamous.

Methods

• Sample Collection: A total of 30 healthy stomach specimens were collected, with 10 from each species—horses, donkeys, and mules.
• Histological Evaluation: Sections of gastric mucosa from these samples were prepared for microscopic examination to verify tissue health and structure.
• Immunohistochemistry: Survivin protein detection was performed using antibody EP119 and the polymer detection method. This technique allows visualization of Survivin localization in tissue sections.
• Quantitative Assessment: The Survivin index—a measure of protein expression—was calculated separately for squamous and glandular mucosa for each animal group.

Results

• Survivin expression was observed in the gastric mucosa across all equid species studied.
• In horses and mules:
  • Survivin was predominantly located in the cytoplasm of cells in both glandular and squamous regions.
  • The Survivin index was significantly higher in the glandular mucosa compared to the squamous mucosa (P = 0.001 for horses and P = 0.041 for mules), indicating stronger expression in glandular tissue.
  • Measured average Survivin indices were approximately:
    • Glandular mucosa: 59 ± 55 (horses), 55 ± 40 (mules)
    • Squamous mucosa: 15 ± 16 (horses), 18 ± 19 (mules)
• In donkeys:
  • The Survivin index also indicated cytoplasmic localization but did not differ significantly between glandular and squamous mucosa (P = 0.506).
  • This suggests a more uniform Survivin expression pattern in donkey gastric mucosa compared to horses and mules.
• Survivin expression localized mainly to the lamina propria (connective tissue below epithelium) and the basal layer of epithelial cells, highlighting its probable role in cell renewal and protection at the base of the mucosal lining.

Conclusions

• The study confirmed that Survivin is expressed in the healthy gastric tissues of horses, donkeys, and mules, primarily within the cytoplasm of cells in the gastric mucosa.
• Differences in Survivin expression between species and gastric mucosa types suggest species-specific patterns, with glandular mucosa having higher expression in horses and mules but not in donkeys.
• This pattern supports the hypothesis that Survivin plays a role in protecting the gastric mucosa and regulating cell renewal.
• The authors recommend further research into Survivin’s role in Equine Gastric Ulcer Syndrome (EGUS) and related conditions to determine if and how Survivin contributes to mucosal protection and adaptation under stress or disease.

Implications for Future Research

• Testing Survivin expression in pathological conditions such as gastric ulcers could clarify its cytoprotective functions in equids.
• Understanding Survivin’s dynamics may lead to potential diagnostic or therapeutic targets for gastric diseases in these species.
• Additional molecular and functional studies are needed to establish causality and mechanistic insights into Survivin’s role in gastric mucosa homeostasis.