Background: Peripheral neuropathy caused chronically by diabetes mellitus is related to exacerbation of oxidative stress and a significant reduction in important endogenous antioxidants. L: -Glutamine is an amino acid involved in defense mechanisms and is a substrate for the formation of glutathione, the major endogenous cellular antioxidant.
Aim: This study investigated the effects of 2% L: -glutamine supplementation on peripheral diabetic neuropathy and enteric glia in the ileum in rats.
Methods: Male Wistar rats were divided into four groups: normoglycemics (N), normoglycemics supplemented with L: -glutamine (NG), diabetics (D), and diabetics supplemented with L: -glutamine (DG). After 120 days, the ileums were processed for HuC/D and S100 immunohistochemistry. Quantitative and morphometric analysis was performed.
Results: Diabetes significantly reduced the number of HuC/D-immunoreactive myenteric neurons per unit area and per ganglion in group D compared with normoglycemic animals (group N). L: -Glutamine (2%) prevented neuronal death induced by diabetes (group DG) compared with group D. The glial density per unit area did not change with diabetes (group D) but was significantly reduced after L: -glutamine supplementation (groups NG and DG). Ganglionic glial density was similar among the four groups. The neuronal area was not altered in groups D and DG. Glial size was reduced in group D; this was reversed by L: -glutamine supplementation (group DG).
Conclusions: We concluded that 2% L: -glutamine had neuroprotective effects directly on myenteric neurons and indirectly through glial cells, which had gliatrophic effects.