Nucleotide structure of equine platelet-derived growth factor-A and -B and expression in horses with induced acute tendinitis.

The research article explores the nucleotide sequence of equine platelet-derived growth factor (PDGF)-A and -B and their expression in horses with intentionally caused acute tendinitis.

Study methodology

The study involved certain specific steps:

• The genes for equine PDGF-A and -B were reverse transcribed (a process by which DNA is made using an RNA template) and sequenced from the synovial tissue mRNA obtained from a 3-year-old horse.
• Injuries were intentionally induced in the tensile region of the superficial digital flexor tendon in 14 horses using collagenase, an enzyme which breaks the peptide bonds in collagen. Three horses were kept aside as uninjured control animals.
• The researchers then harvested tendons and isolated total RNA from the horses at different intervals – 1, 2, 4, 8, and 24 weeks after the collagenase injection.
• The researchers analyzed the temporal gene expression for PDGF-A and -B using quantitative PCR analysis.

Results

The results presented in the research are as follows:

• The nucleotide structure of equine PDGF-A showed 83.8% sequence and 87.5% peptide homology with the human PDGF-A, but it varied by 70 base pairs from the human sequence.
• Equine PDGF-B showed great similarity to the human gene, sharing 90.3% of the nucleotide sequence and 91.7% of the peptide.
• The measurement of PDGF-A mRNA expression in collagenase-induced tendinitis injuries remained unchanged when compared to normal control tendons over the duration of the study.
• The measurement of PDGF-B mRNA, however, decreased over time, and by the 24th week was significantly lower than expression in normal and acutely injured tendons.

Conclusions and Future Applications

Upon interpretation of the research findings, it was concluded that:

• The injured tendon exhibits a minimal response in terms of PDGF-A or -B mRNA production. This indicates that the natural ability of the horse’s body to increase growth factor production in response to injury is limited.
• Applying solutions with PDGF-A or -B to the injury site in the first 2 to 4 weeks might enhance the weak PDGF response to injury. This could potentially accelerate the injury healing process by stimulating cell growth and division.