Post-mortem stability of RNA in skeletal muscle and adipose tissue and the tissue-specific expression of myostatin, perilipin and associated factors in the horse.
Authors: Morrison Philippa K, Bing Chen, Harris Patricia A, Maltin Charlotte A, Grove-White Dai, Argo Caroline McG
Journal: PloS one
Summary
# Editorial Summary Morrison and colleagues examined the post-mortem degradation of RNA in equine skeletal muscle and adipose tissue, alongside tissue-specific expression patterns of genes regulating muscle mass (myostatin, its receptor ActRIIB, and follistatin) and fat metabolism (perilipin)—pathways implicated in obesity predisposition across mammalian species. Using tissues from seven Thoroughbreds at a commercial abattoir, they collected samples at intervals up to six hours post-mortem and assessed RNA integrity through optical density analysis and electrophoresis, whilst quantifying gene and protein expression across 17 anatomically distinct tissues using quantitative real-time PCR and Western blotting. Skeletal muscle yielded usable RNA for up to two hours post-mortem, but adipose tissue proved considerably more fragile, with RNA integrity compromised beyond 30 minutes—a critical finding for anyone conducting molecular research on equine samples. Myostatin and ActRIIB expression was almost entirely restricted to skeletal muscle, whilst perilipin showed exclusive adipose tissue expression; follistatin demonstrated wider tissue distribution, suggesting a more complex regulatory role than the muscle-specific factors. These results establish practical sampling windows for RNA work in horses and provide baseline tissue-specific expression data for the myostatin and perilipin pathways, informing future investigations into the molecular mechanisms underpinning equine obesity—particularly relevant given obesity's prevalence and welfare implications in leisure horse populations.
Read the full abstract on PubMed
Practical Takeaways
- •If collecting equine tissue samples for gene/protein expression studies at slaughter, prioritize adipose tissue collection within 30 minutes post-mortem to maintain RNA integrity; skeletal muscle samples remain viable longer (up to 2 hours)
- •Myostatin and perilipin represent tissue-specific targets for investigating obesity pathways in horses—myostatin in muscle studies and perilipin in fat depot studies
- •Understanding the distinct tissue localization of these regulatory pathways could help develop targeted nutritional or management strategies to address the high prevalence of obesity in leisure horses
Key Findings
- •High-quality RNA can be extracted from equine skeletal muscle for up to 2 hours post-mortem, but adipose tissue RNA degrades within 30 minutes under commercial abattoir conditions
- •Myostatin and its receptor (ActRIIB) are almost exclusively expressed in skeletal muscle, not in adipose tissue or organs
- •Perilipin gene and protein expression is almost exclusively localized to adipose tissue, making it the primary marker for lipolysis regulation
- •Follistatin shows diverse expression across multiple tissues including organs, adipose depots, and skeletal muscles, suggesting broader regulatory roles than myostatin