Figure 9.

Electron microscopy of cross-sections through the region surrounding the distal myelinated optic nerve demonstrated that axons with normal axoplasm were surrounded by myelin sheaths in the normal control eyes (A). In the diabetic retinas, myelin sheaths were thinned and unorganized, and axoplasm was sparse compared to the control retinas (B). In the retinas of diabetes model mice that underwent nicotinamide treatment, myelin sheaths and axoplasm were relatively preserved (C). Scale bars = 0.5 μm. NAM, nicotinamide. Red asterisk, axoplasm. Red arrow, myelin sheaths.