Aberrant skeletal muscle morphogenesis and myofiber differentiation characterize equine myotonic dystrophy
Fig 2
Muscle histopathology in frozen sections of eMD horses.
(A) Normal HE stain of the gluteal muscle of a 4-year-old control horse (C2). (B) Marked fiber size variation, anguloid atrophy, fiber splitting (arrow) internalized myonuclei and increased endomysial connective tissue in semimembranosus muscle of 2-month-old eMD1 (HE 20X). (C) Large myofibers and anguloid and angular (arrow) atrophied fibers, fiber splitting and internalized nuclei in gluteal muscle of 3-year-old eMD3 (HE 20X). (D) Marked variation in fiber sizes, anguloid and angular atrophy (arrow) and internalized nuclei in 3-month-old eMD2 (HE 40X) (E) Areas of marked fiber size variation with a focal area of larger fibers juxtaposed with atrophied fibers in gluteal muscle of 3-month-old eMD2 (HE 20X). (F) Normal appearing triceps muscle in eMD2 (HE 10X) (G) Internalized myonuclei and sarcoplasmic masses (arrow) in 3-year-old eMD5 (modified Gomori Trichrome 40X). (H) Normal gluteal muscle of 3-year-old control horse C2 (modified Gomori Trichrome 40X).