[Facial nerve injuries cause changes in central nervous system microglial cells]

Area of Science:

• Neuroscience
• Glial Cell Biology
• Neuroinflammation

Background:

• Previous research detailed neuronal changes in the motor cortex after facial nerve injury.
• The role of surrounding glial cells, particularly microglia, in these adaptations remained largely unexplored.

Purpose of the Study:

• To investigate the impact of unilateral facial nerve injury on microglial proliferation and activation within the primary motor cortex.
• To differentiate responses between reversible and irreversible nerve injury models.

Main Methods:

• Immunohistochemistry was employed to identify and quantify microglial cells in rat brain tissue.
• Rats underwent either reversible (crush) or irreversible (section) facial nerve lesions.
• Tissue was analyzed at multiple time points post-injury (1, 3, 7, 21, 35 days) and compared to control and sham groups.

Main Results:

• Irreversible facial nerve injury led to significant microglial proliferation and activation in the primary motor cortex between 3 and 7 days post-lesion.
• Reversible injury showed a significant microglial proliferation only at 3 days post-lesion.

Conclusions:

• Unilateral facial nerve injury induces microglial responses in the primary motor cortex.
• These microglial changes may contribute to the previously observed morphological and electrophysiological alterations in motor cortex pyramidal neurons.