Abstract

BACKGROUND
Multiple etiology of diabetic neuropathy has been proposed, including altered polyol metabolism, superoxide radical formation, protein glycation, vascular insufficiency, blunted nitric oxide production and neurotrophic factor (NTF) deficiency. Nerve growth factor (NGF) is a member and family of neurotrophic factors. NGF is produced in tissues innervated by its responsive neurons. In the peripheral nervous system, NGF messenger RNA (mRNA) is produced in target fields of small pain and temperature-mediating dorsal root ganglia (DRG) sensory neurons and sympathetic neurons. NGF has been shown to promote their survival, differentiation, and maintenance. However, the mechanism of neuronal damage in diabetes and the effect of NGF on diabetic neuropathy are not clear. METHODS: In order to clarify the effect of NGF, the changes of cell viability were evaluated by MTT assay on mouse cultured dorsal root ganglion cells which were grown with media containing concentrations of high glucose for inducing hyperglycemic condition. Furthermore, the neuroprotective effect of nerve growth factor (NGF) against hyperglycemia-induced dorsal root ganglion cell changes were also examined. RESULTS: 1. Cell viability of cultured mouse dorsal root ganglion cells treated with hyperglycemic media made with 15, 25 mM glucose was markedly decreased in a dose-dependent manner when compared with control medium (normoglycemic medium) containing concentration of 5.5 mM glucose (p<0.05). 2. Cultured dorsal root ganglion cells exposed to hyperglycemic medium made with 25 mM glucose for 72 hours showed morphological changes such as dissociations, loss of neurites and decrease of cell viability (p<0.05). 3. Pretreatment of 150 ng/mL NGF for 2 hours significantly increased the cell viability of cultured dorsal root ganglion cells which exposed to hyperglycemic medium (25 mM glucose for 72 hours). CONCLUSION: Findings from this study suggested that hyperglycemic condition induces the decrease of cell viability and morphological changes (loss of neurites, dissociation) on cultured dorsal root ganglion cells of mouse. Furthermore, selective neurotrophic factors such as NGF are very effective in preventing dysfunction and morphological changes of DRG cells induced by hyperglycemic condition.

• Keywords: Nerve growth factor;Diabetic neuropathy;MTT assay;Dorsal root ganglion cell culture;Hyperglycemia;