Nerve Injury-Induced Immune Responses in the Taste Bud Target Field.

Area of Science:

• Neuroscience
• Immunology
• Regenerative Medicine

Background:

• Chorda tympani (CT) nerve damage causes taste bud degeneration and taste loss.
• Interleukin-1 receptor 1 (Il1r) signaling is crucial for taste bud regeneration.
• The role of Il1r in immune responses following CT nerve injury is not fully understood.

Purpose of the Study:

• To investigate the impact of experimental axotomy on innate immune cell populations in the anterior taste field.
• To compare immune responses in wild-type and Il1r knockout mice after unilateral CT nerve sectioning.

Main Methods:

• Unilateral CT nerve sectioning was performed in Il1r knockout and wild-type mice.
• Changes in innate immune cell populations, including M2-like macrophages, were analyzed in the anterior taste field post-injury.

Main Results:

• Wild-type mice showed significant increases in CD45+ immune cells and CD68+/CD206+ M2-like macrophages near anterior taste buds at 2 and 5 days post-injury.
• Il1r knockout mice did not exhibit these immune cell increases.
• Taste bud degeneration occurred at similar rates in both wild-type and Il1r knockout mice.

Conclusions:

• Suppressed immune responses in Il1r knockout mice are not the primary cause of taste bud degeneration after CT nerve injury.
• Pro-regenerative M2-like macrophages may contribute to taste bud regeneration and functional recovery in the injured peripheral taste system.