Benevides Ethan S, Rana Sabhya, Fuller David D
Department of Physical Therapy, University of Florida, Gainesville, FL 32601, United States; Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL 32601, United States.
Department of Physical Therapy, University of Florida, Gainesville, FL 32601, United States; Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL 32601, United States; McKnight Brain Institute, University of Florida, Gainesville, FL 32601, United States.
Respir Physiol Neurobiol. 2025 Mar 26;336:104421. doi: 10.1016/j.resp.2025.104421.
We tested the hypothesis that activation of DREADDs in the mid-cervical spinal cord could restore diaphragm activation during spontaneous breathing after cervical spinal cord injury (SCI). Adult Sprague Dawley rats (n = 7) received bilateral mid-cervical ventral horn injections of an AAV construct encoding an excitatory DREADD (AAV9-hSyn-HA-hM3D(Gq)-mCherry; titer: 2.44 × 10 vg/mL). Subsequently, diaphragm electromyogram (EMG) activity was recorded during spontaneous breathing under isoflurane anesthesia. The selective DREADD ligand JHU37160 (J60) was administered intravenously at acute (3 days), sub-acute (2 weeks), and chronic (2 months) timepoints following cervical hemilesion at spinal level C2. J60 administration resulted in robust increases in diaphragm EMG output at all timepoints, and near-complete restoration of diaphragm EMG activity from the paralyzed hemi-diaphragm in 50 % of trials. Administration of J60 to DREADD naïve, spinal intact rats (n = 8) did not produce an increase in diaphragm activity. These proof-of-concept results indicate that refinement of this technique may provide a strategy for improving diaphragm activation after cervical SCI.
在颈脊髓损伤（SCI）后，激活颈中部脊髓中的DREADDs能够在自主呼吸过程中恢复膈肌激活。成年Sprague Dawley大鼠（n = 7）接受双侧颈中部腹角注射编码兴奋性DREADD的腺相关病毒构建体（AAV9-hSyn-HA-hM3D(Gq)-mCherry；滴度：2.44×10 vg/mL）。随后，在异氟烷麻醉下记录自主呼吸过程中的膈肌肌电图（EMG）活动。在脊髓C2水平进行颈半横断后的急性（3天）、亚急性（2周）和慢性（2个月）时间点，静脉注射选择性DREADD配体JHU37160（J60）。在所有时间点，J60给药均导致膈肌EMG输出显著增加，并且在50%的试验中，瘫痪半侧膈肌的EMG活动几乎完全恢复。对未接触过DREADD且脊髓完整的大鼠（n = 8）注射J60并未使膈肌活动增加。这些概念验证结果表明，改进该技术可能为改善颈脊髓损伤后的膈肌激活提供一种策略。
