Cytoarchitecture of muscle in a genetic model of murine diabetes

Abstract

Although diabetic neuropathy is well documented, diabetic myopathy is not, except for descriptions of diabetic patients with muscular weakness thought to be due to metabolic changes in the muscle. Muscle and nerve are dependent on each other for normal structure and function; since the peripheral nerve is damaged in diabetes, one would expect concomitant changes in the muscle. This study examines the cytoarchitecture of diabetic muscle. The extensor digitorum longus (EDL) muscles from 165-day-old C57BL/KsJ dbm mice were examined using electron microscopy. Morphological analysis of the diabetic EDL revealed that a significant number of the myofibers, examined within the midbelly region of the muscle, exhibited various degrees of degeneration, signs of denervation, and abnormal lipid stores. Both myoneural junctions and muscle spindles showed significant signs of degeneration, denervation, and abnormal structure. Thus the morphologic changes seen could account for the physiologic changes seen in diabetic muscle.

Proximal skeletal muscle alterations in streptozotocin‐diabetic rats: A histochemical and morphometric analysis

“…Although most of the previous studies have described alterations of distal muscles (Feczko and Klueber, 1988;Chokroverty et al, 1988;Cotter et al, 1989;Klueber et al, 19891, our results suggest that experimental diabetes also produces structural alterations in proximal skeletal muscle. In addition to the existence of type I1 myofiber atrophy, the appearance of type IIC fibers without degenerative changes in the diabetic rectus femoris suggests a possible muscle denervation (Sunderland, 1985).…”

“…Nevertheless, metabolic and vascular implications should not be excluded, because they also produce differential effects in the fiber type as well as mitochondria1 alterations (Carpenter and Karpati, 1984). Perhaps the changes seen can be ascribed to a combination of these three factors, as has been suggested by Bestetti et al (1981) and Feczko and Klueber (1988) …”

“…In the current study, however, the diabetic myofibers were affected uniformly, indicating a more diffuse andlor distal location of the damage. In fact, several authors (Chokroverty, 1982;Pachter, 1986;Drakontides and Ogawa, 1986;Feczko and Klueber, 1988) have reported motor endplate alterations in diabetic muscle, supporting the idea of a preferential distal alteration. On the other hand, Sima and Thibert (1982) maintain that multiple infarcts in the spinal ventral roots are the structural mechanism that causes the muscular complications in diabetic patients.…”

Striated muscle fiber size, composition, and capillary density in diabetes in relation to neuropathy and muscle strength 糖尿病患者的横纹肌纤维尺寸、成份以及毛细血管密度与神经病变以及肌肉强度相关

“…Similar findings of altered fiber type distribution have been reported in other studies in both animals and humans with diabetes mellitus; however, neuropathy was not the focus in these studies and, accordingly, manifestations of muscle fiber degeneration due to DPN were not reported . Although most studies have investigated metabolic disturbances following diabetes in skeletal muscle, neuropathy has been mentioned as a possible factor by some authors …”

“…[11][12][13] Although most studies have investigated metabolic disturbances following diabetes in skeletal muscle, neuropathy has been mentioned as a possible factor by some authors. 14,15 Changes in capillary structure and density have been reported in both human and experimental diabetic striated muscle, but a relationship with DPN or muscle strength has never been sought. 11,16,17 Therefore, the aim of the present study was to quantitatively evaluate muscle fiber size and distribution, as well as capillary density, in T1D and T2D patients in relation to DPN.…”