Relationship among myofiber shapes, myofiber cross-sectional area, and circularity parameter

Research Objectives: To clarify the relationship among myofiber shapes, myofiber cross-sectional area, and circularity parameter.

Design: Randomized controlled trial study.

Setting: Department of Physical Therapy, Japan University of Health Sciences.

Participants: 500 myofibers in soleus muscles of 11-week-old male Wistar rats.

Interventions: Soleus muscles of five 11-week-old male Wistar rats were collected as samples. Muscle samples were rapid-frozen in isopentane—cooled in dry ice and acetone—and sliced into 10-μm slices in a cryostat, then stained with hematoxylin–eosin. The NIH-ImageJ software was used to analyze the number of corners that were counted according to the proposed criteria and myofiber cross-sectional area (MFCSA) of 500 myofibers.

Main Outcome Measures: Relationship among the approximate shape of myofiber cross-section (MFCS), myofiber cross-sectional area, and circularity parameter.

Results: As for the approximate shape of MFCS, the proportion of pentagons was 41%, which was the highest among polygons. A weak positive correlation was noted between the corner count and MFCSA, which indicated that polygons with more number of corners were associated with larger MFCSA.

Conclusions: It was suggested that the MFCS of soleus muscle had many approximate shape of pentagons. Moreover, a correlation was observed between MFCS and MFCSA, suggesting that it was also associated with the relevant functional features.

Author(s) Disclosures: The authors declare no conflicts of interest associated with this manuscript.