Morphological and structural alterations in skeletal muscle of STZ-induced diabetic rats revealed by light and electron microscopy

Objectives: This study investigates morphological and ultrastructural changes in skeletal muscles of diabetic rats induced by streptozotocin (STZ) using light microscopy, field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). Together, these imaging methods allow for detailed visualization of tissue-level and subcellular changes in the gastrocnemius muscle, offering an integrated view of diabetes-related pathology. Materials and Methods: Diabetes was induced in male Sprague-Dawley rats through a single intraperitoneal injection of STZ (at 65 mg/kg). After 30 days of diabetes maintenance, the rats were euthanized, and gastrocnemius muscle samples were harvested for Hematoxylin and Eosin (H&E), Masson’s Trichrome (MT), and histochemical staining. Morphological features were examined using FESEM, and ultrastructural organization was analyzed using TEM. Results: Our findings confirm that hyperglycemia severely damages skeletal muscle in STZ-induced diabetic rats, characterized by extensive myofiber injury, atrophy, and mitochondrial disruptions. Ultrastructural analysis revealed extensive architectural disruptions and clear deviations from normal morphology. Conclusions: Our study provides evidence of profound structural and cellular alterations in diabetic skeletal muscles and offers insights for developing strategies to mitigate pathological changes, preserve muscle integrity, and support functional recovery.