Gene expression of proteolytic systems and growth regulators of skeletal muscle in horses with myopathy associated with pituitary pars intermedia dysfunction.

The research delves into the gene expression of various proteolytic systems and growth regulators in the skeletal muscle of horses afflicted with a specific type of myopathy related to pituitary pars intermedia dysfunction. Mainly, the report found that there was a higher expression of m-calpain in horses with this condition, suggesting that calpains could have a role in muscle atrophy development in such cases.

Research Methods

• The study utilized 14 horses with pituitary pars intermedia dysfunction (PPID)-associated myopathy and 7 healthy control horses for the exploration.
• The horses in both groups were age-matched, ranging from 15 to 28 years old.
• Muscle biopsy samples were gathered from the horses in both groups. The samples underwent RNA and cDNA extraction processing.
• The researchers carried out a validation process for the most stable housekeeping genes associated with skeletal muscle. These genes were subsequently utilized as a basis to compare the gene expression of different proteolytic systems, i.e., caspases, cathepsins, calpains, and ubiquitins.
• Additionally, the gene expression of several negative regulators of muscle growth, such as myostatin and inflammatory cytokines interleukin-1beta, interleukin-6, and tumor necrosis factor-alpha, were also examined.

Research Findings

• The research findings showed no significant discrepancy between the two groups in terms of the expression of the primary proteolytic systems, except for m-calpain.
• The m-calpain was found to be more present in horses with PPID.
• There was no detectable difference in gene expressions of myostatin, interleukin-1beta, interleukin-6, and tumor necrosis factor-alpha between the two groups.

Research Conclusion

• Based on the research results, the higher expression of m-calpain in horses suffering from PPID could suggest that calpains play a significant part in muscle atrophy development in these cases.
• Though, in spite of this finding, due to potential posttranslational alterations which may modify protein activation, deactivation, and functions, other mechanisms of muscle atrophy are not ruled out and could still play a role.