Figure 1.

Effects of epalrestat, an ARI, on the ultrastructure of sciatic nerve cells in DM rats.

Pathological changes at various stages of DM induced by streptozotocin. Sciatic nerves were analyzed using electron microscopy. (Scales: A, D: left and right, 2 μm; B: left 2 μm, right 5 μm; C: left 2 μm, right 10 μm). (A, B) The nDM (ARI⁻) and nDM (ARI⁺) groups: myelinated nerve fiber layers are clear, myelin sheath structure is smooth, full, and complete without distorting variant form. Schwann cell membrane is intact; the nucleus is clearly visible and the nuclear membrane is unbroken. (C) DPN (ARI⁻) group: myelin sheath cells become deranged in the medullated fibers of sciatic nerves; shrinkage, deformity and inhomogeneity can be observed in neurites. Structures of Schwann cells is blurred and vacuoles degenerated, but the integrity of cell membrane was not lost. Cells of non-myelinated nerves swelled, with the presence of irregular morphology and widened cellular spaces. Schwann cells have shrunk. (D) DPN (ARI⁺) group: pathological structures of neurites and myelin are significantly improved after treatment with epalrestat. Deranged myelin sheath cells recover and Schwann cell swelling is attenuated. DM: Diabetes mellitus; nDM: non-diabetes mellitus; DPN: diabetic peripheral neuropathy; ARI: aldose reductase inhibitor.