Randomized trial quantifies neural projections impacting upper airway function in aging populations, suggesting implications for obstructive sleep apnea.
Key Points
This research aims to assess how aging affects catecholaminergic innervation from A1C1 neurons to the hypoglossal nucleus and NTS and its relationship with obstructive sleep apnea.
Young (3-4 months; n=13) and old (20-23 months; n=8) mice underwent unilateral microinjections of AAV8 to the A1/C1 nucleus.
Mice were perfused four weeks later, and sections underwent immunohistochemistry to assess ChR2-positive neurons and axonal projections.
Statistical analysis included linear regression and ANCOVA to evaluate the impact of age on projections to the hypoglossal nucleus and NTS.
The number of ChR2-positive neurons in A1C1 positively correlated with axonal projections to the hypoglossal nucleus (p=0.0006) and NTS (p=0.0004).
Aging significantly reduced projections in older mice's hypoglossal nucleus at AP -7.2 for both ventral (p=0.004) and dorsal (p=0.026) subdivisions.
ChR2-positive projections to the NTS were negatively impacted by age bilaterally (p=0.026) at AP -7.2.