Hematoxylin eosin stain

Muscle tissues were fixed separately in 10% buffered neutral formaldehyde
solution (Sigma Chemical Company, Germany) for histopathological examination.
Samples were embedded in paraffin blocks, and 5-micrometer sections were taken.
They were stained with hematoxylin-eosin stain (Sigma Chemical Company,
Germany). 20 lens magnification was used (Olympus BX51 TF, United States of
America). Interstitial edema, muscle fiber degeneration, nuclear centralization,
inflammatory cell infiltration, disorganization, and necrosis were determined as
histopathological parameters. The scoring (none: 0, yes: 1, significant: 2) was
arranged for each histopathological parameter^{[26 (link)]}. Damage was estimated by summing up
the parameters. The histopathological score was determined and recorded for each
sample.

Experimental myocardial samples were fixed, embedded in paraffin, sectioned and mounted on glass slides. Hematoxylin-eosin stain (Sigma Aldrich, MI) was performed for histological analysis. Collagen deposition was detected using picrosirius red staining [20 (link)]. Luna’s technique was performed for the specific visualization of eosinophil granules [21 (link)]. The presence of eosinophils was also assessed by immunohistochemistry using mouse anti-eosinophil major basic protein (EMBP) antibody.