BDNF Influence on Adult Terminal Axon Sprouting after Partial Deafferentation

Area of Science:

• Neuroscience
• Molecular Biology
• Ophthalmology

Background:

• Brain-derived neurotrophic factor (BDNF) is crucial for neuronal survival, development, and synaptic plasticity.
• BDNF is present in the oculomotor system, regulating motoneuron afferent composition and firing patterns.
• BDNF expression and axonal sprouting increase after partial deafferentation of extraocular motoneurons.

Purpose of the Study:

• To investigate the active role of BDNF in promoting axon sprouting after partial deafferentation of medial rectus motoneurons.
• To determine if BDNF can stimulate axon sprouting in the absence of neuronal lesions.

Main Methods:

• Partial deafferentation of medial rectus motoneurons was induced by transecting the ascending tract of Deiters.
• Exogenous BDNF was injected into the medial rectus muscle.
• Axon terminal sprouting was assessed using calretinin immunostaining.
• Experiments were also conducted on intact animals without lesions.

Main Results:

• Exogenous BDNF significantly stimulated terminal axon growth, fully restoring synaptic coverage around motoneuron somata.
• Calretinin staining in the neuropil increased beyond control levels after BDNF treatment.
• BDNF demonstrated the ability to stimulate axonal sprouting even in intact nervous systems.

Conclusions:

• BDNF plays an active role in the plastic adaptations occurring after partial deafferentation of oculomotor neurons.
• BDNF can promote axonal sprouting and synaptic regeneration in the central nervous system.
• Targeted BDNF application may hold therapeutic potential for conditions involving neuronal damage or loss of synaptic function.