Downregulated Brain-Derived Neurotrophic Factor-Induced Oxidative Stress in the Pathophysiology of Diabetic Retinopathy.

Brain-derived neurotrophic factor (BDNF), a member of neurotrophin growth factor family, physiologically mediates induction of neurogenesis and neuronal differentiation, promotes neuronal growth and survival and maintains synaptic plasticity and neuronal interconnections. Unlike the central nervous system, its secretion in the peripheral nervous system occurs in an activity-dependent manner. BDNF improves neuronal mortality, growth, differentiation and maintenance. It also provides neuroprotection against several noxious stimuli, thereby preventing neuronal damage during pathologic conditions. However, in diabetic retinopathy (a neuromicrovascular disorder involving immense neuronal degeneration), BDNF fails to provide enough neuroprotection against oxidative stress-induced retinal neuronal apoptosis. This review describes the prime reasons for the downregulation of BDNF-mediated neuroprotective actions during hyperglycemia, which renders retinal neurons vulnerable to damaging stimuli, leading to diabetic retinopathy.