Electrophysiological measurements in response to ES applied at different timing in nondiabetic and diabetic rats (*<i>p</i><0.05 compared to nondiabetic normal group, #<i>p</i><0.05 compared to diabetic control group, $<i>p</i><0.05 compared to group C, &<i>p</i><0.05 compared to group B, ^<i>p</i><0.05 compared to group A).

<p>Electrophysiological measurements in response to ES applied at different timing in nondiabetic and diabetic rats (*<i>p</i><0.05 compared to nondiabetic normal group, #<i>p</i><0.05 compared to diabetic control group, $<i>p</i><0.05 compared to group C, &<i>p</i><0.05 compared to group B, ^<i>p</i><0.05 compared to group A).</p

Photomicrographs demonstrating anti-rat CD68 immunoreactivity in macrophages (arrows) from cross sections of distal nerve cables of (a) group A, (b) group B, (c) group C, (d) group D, (e) and group E.

<p>(f) Note the significantly increased density of macrophages in diabetic animals receiving a higher frequency of ES. Each data point represents the mean ± SEM. Bar = 25 µm.</p

Images of regenerative nerves in transverse section after ES treatment applied at different timing in diabetic rats from (A) group A (PID 1), (B) group B (PID 8), (C) group C (PID 15), (D) group D (no ES), and in nondiabetic normal rats from (E) group E (no ES).

<p>Nerves show the typical aspect of a regenerated nerve, with myelinated axons (MA), Schwann cells (SC) and blood vessels (BV), which tended to disperse in the endoneurium. (F) Comparisons of cross-sectional area and (G) axon numbers (*<i>p</i><0.05 compared to nondiabetic normal group, #<i>p</i><0.05 compared to diabetic control group, $<i>p</i><0.05 compared to group C, &<i>p</i><0.05 compared to group B, ^<i>p</i><0.05 compared to group A). Each data represents the mean ± standard deviation. Bar = 20µm.</p

Photomicrographs demonstrating CGRP-IR (arrows) in dorsal horn in the lumbar spinal cord after injury of a normal control from an animal of (a) group A, and the diabetic sciatic nerves after ES treatment from (b) group B (0 Hz), (c) group C (2 Hz), (d) group D (20 Hz), and (e) group E (200 Hz).

<p>(f) Note the significantly increased CGRP-IR area ratios in diabetic animals receiving a higher frequency of ES. Each data point represents the mean ± SEM. Bar = 200 µm.</p

Blood perfusion to the ipsilateral hindpaw in response to ES applied at different timing in nondiabetic and diabetic rats (*<i>p</i><0.05 compared to nondiabetic normal group, #<i>p</i><0.05 compared to diabetic control group, &<i>p</i><0.05 compared to group B, ^<i>p</i><0.05 compared to group A).

<p>Blood perfusion to the ipsilateral hindpaw in response to ES applied at different timing in nondiabetic and diabetic rats (*<i>p</i><0.05 compared to nondiabetic normal group, #<i>p</i><0.05 compared to diabetic control group, &<i>p</i><0.05 compared to group B, ^<i>p</i><0.05 compared to group A).</p

PCR primers.

<p>PCR primers.</p

Photomicrographs demonstrating anti-rat CD68 immunoreactivity in macrophages (arrows) from cross sections of distal nerve cables after ES treatment applied at different timing in diabetic rats from (A) group A (PID 1), (B) group B (PID 8), (C) group C (PID 15), (D) group D (no ES), and in nondiabetic normal rats from (E) group E (no ES).

<p>(F) Macrophage density comparisons (*<i>p</i><0.05 compared to nondiabetic normal group, #<i>p</i><0.05 compared to diabetic control group, $<i>p</i><0.05 compared to group C, &<i>p</i><0.05 compared to group B, ^<i>p</i><0.05 compared to group A). Each data represents the mean ± standard deviation. Bar = 20 µm.</p

Photomicrographs demonstrating CGRP-IR (arrows) in laminae I-II of dorsal horn in the lumbar spinal cord after injury of sciatic nerves after ES treatment applied at different timing in diabetic rats from (A) group A (PID 1), (B) group B (PID 8), (C) group C (PID 15), (D) group D (no ES), and in nondiabetic normal rats from (E) group E (no ES).

<p>(F) Comparisons of CGRP-IR area ratios (*<i>p</i><0.05 compared to nondiabetic normal group, #<i>p</i><0.05 compared to diabetic control group, $<i>p</i><0.05 compared to group C, &<i>p</i><0.05 compared to group B, ^<i>p</i><0.05 compared to group A). Each data represents the mean ± standard deviation. Bar = 200 µm.</p

Morphometric analysis of axonal regeneration and remyelination.

<p>It was noted that the number of myelinated axons in the ES-treated groups at 20 and 200 Hz was much greater than that in the ES groups at 0 and 2 Hz.</p

The time sequence of the study with stimulation periods as shaded blocks and rest periods as open blocks; induction of diabetes was performed at 7 days before the nerve surgery and all animals were sacrificed on PID 30.

<p>Abbreviation: PID, postinjury day.</p