Growth hormone modulates epithelial intercellular junctions structure and intestinal permeability in zebrafish

Area of Science:

• Gastroenterology
• Endocrinology
• Zebrafish models

Background:

• Intestinal permeability is regulated by tight junctions (TJs) within the apical junctional complex (AJC).
• Growth hormone (GH) signaling disruptions are linked to gastrointestinal issues, but effects of chronic GH elevation on the gut barrier are unclear.

Purpose of the Study:

• To investigate the impact of GH overexpression on intestinal permeability and epithelial structure.
• To utilize a transgenic zebrafish model to study GH's effects on the gut.

Main Methods:

• Comparative analysis of gh-transgenic zebrafish and non-transgenic siblings.
• Transmission electron microscopy to assess AJC integrity.
• Quantitative real-time PCR (qRT-PCR) for TJ-related gene expression.
• Assessment of intestinal permeability using RITC-dextran.

Main Results:

• GH overexpression led to increased AJC disruption in zebrafish.
• Transcription of TJ-related genes (cldn15a, oclna, zo1a) was elevated.
• Intestinal permeability to macromolecules was significantly increased in GH-overexpressing fish.

Conclusions:

• Chronic GH overexpression disrupts intestinal epithelial architecture and enhances paracellular permeability.
• Suggests a link between GH signaling and intestinal barrier modulation.
• Potential adaptive mechanism for increased energy demands in anabolic states.