Figure 4.

Morphometric analysis of the ON from control rats and from diabetic rats after 6 weeks of diabetes. Light micrographs of semithin transverse sections at the proximal and distal myelinated portions from a control (A and B) and a diabetic rat (F and G). Size frequency histograms showing the axon area distribution at the distal ON portion from a representative control (C) and a diabetic rat (H). Note the shift to smaller-sized axons found in the diabetic rat compared with an age-matched control. In diabetic rats, significant reductions were found in total axon number (D) and mean axon area (E). I: Axonal diameter distribution in controls and in animals after 6 weeks of diabetes. A significant decrease in the number of middle and large (but not smaller) axons was observed in diabetic animals. Data are mean ± SEM (n = 5 animals per group). *P < 0.01 versus age-matched controls, by Student's t-test. Scale bar = 25 μm (G).