Transcriptional Time Course After Rotator Cuff Tear

Area of Science:

• Orthopedics
• Muscle Pathobiology
• Molecular Biology

Background:

• Rotator cuff tears are common in older adults, leading to chronic muscle atrophy and fatty infiltration.
• Current research on muscle dysfunction post-rotator cuff tear often uses limited time points and animal models.
• A gap exists in understanding the dynamic, time-dependent transcriptional changes in muscle following rotator cuff tears.

Purpose of the Study:

• To investigate the temporal transcriptional landscape of supraspinatus muscle after tenotomy in a rabbit model.
• To identify unique, time-dependent gene expression patterns that may contribute to chronic muscle degeneration.
• To correlate transcriptional changes with morphological sequelae in rotator cuff muscle.

Main Methods:

• Rabbit supraspinatus muscle tissue was collected at high temporal resolution (1, 2, 4, 8, and 16 weeks) post-tenotomy.
• RNA sequencing and subsequent analyses were performed to identify differentially expressed genes.
• Histological analysis was conducted to correlate gene expression with tissue morphology.

Main Results:

• A significant number of differentially expressed genes were observed at 1 week post-tenotomy, decreasing by 8 weeks.
• A notable resurgence and transition of gene expression occurred at 16 weeks post-tenotomy, a pattern not previously reported.
• Transcriptional changes correlated with histological findings and were enriched for pathways involved in lipid metabolism, apoptosis, and extracellular matrix remodeling.

Conclusions:

• Rotator cuff tears induce complex, time-dependent transcriptional changes in muscle, including a late resurgence at 16 weeks.
• These dynamic changes provide insights into the biological mechanisms underlying chronic muscle degeneration after rotator cuff tears.
• The findings highlight the need for high-temporal-resolution studies to fully understand muscle pathobiology following rotator cuff injury.