Respiratory motor outputs following unilateral midcervical spinal cord injury in the adult rat

2014 ◽  
Vol 116 (4) ◽  
pp. 395-405 ◽  
Author(s):  
Kun-Ze Lee ◽  
Yi-Jia Huang ◽  
I-Lun Tsai
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Tidal Volume ◽  
Spinal Injury ◽  
Whole Body ◽  
Adult Rats ◽  
Cord Injury ◽  
Burst Amplitude ◽  
Respiratory Recovery ◽  
The Impact

The present study was designed to investigate the impact of midcervical spinal cord injury on respiratory outputs and compare respiratory recovery following high- vs. midcervical spinal injury. A unilateral hemisection (Hx) in the spinal cord at C2 or C4 was performed in adult rats. Respiratory behaviors of unanesthetized animals were measured at normoxic baseline and hypercapnia by whole body plethysmography at 1 day and 1, 2, 4, and 8 wk after spinal injury. C2Hx and C4Hx induced a similar rapid shallow breathing pattern at 1 day postinjury. The respiratory frequency of C4Hx animals gradually returned to normal, but the tidal volume from 1 to 8 wk postinjury remained lower than that of the control animals. Linear regression analyses indicated that the tidal volume recovery was greater in the C4Hx animals than in the C2Hx animals at the baseline, but not at hypercapnia. The bilateral phrenic nerve activity was recorded in anesthetized animals under different respiratory drives at 8–9 wk postinjury. The phrenic burst amplitude ipsilateral to the lesion reduced following both high- and midcervical Hx; however, the ability to increase activity was lower in the C4Hx animals than in the C2Hx animals. When the data were normalized by the maximal inspiratory effort during asphyxia, the phrenic burst amplitude enhanced in the C4Hx animals, but reduced in the C2Hx animals compared with the control animals. These results suggest that respiratory deficits are evident following midcervical Hx, and that respiratory recovery and neuroplasticity of phrenic outputs are different following high- vs. midcervical spinal injury.

Impact of cervical spinal cord injury on the relationship between the metabolism and ventilation in rats

2021 ◽  
Author(s):  
Tzu-Ting Chiu ◽  
Kun-Ze Lee
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Tidal Volume ◽  
Cervical Spinal Cord ◽  
Cervical Spinal Cord Injury ◽  
Male Rats ◽  
Whole Body ◽  
Post Injury ◽  
Chronic Injury ◽  
Cord Injury

Cervical spinal cord injury typically results in respiratory impairments. Clinical and animal studies have demonstrated that respiratory function can spontaneously and partially recover over time after injury. However, it remains unclear whether respiratory recovery is associated with alterations in metabolism. The present study was designed to comprehensively examine ventilation and metabolism in a rat model of spinal cord injury. Adult male rats received sham (i.e., laminectomy) or unilateral mid-cervical contusion injury (height of impact rod: 6.25 or 12.5 mm). Breathing patterns and whole-body metabolism (O2 consumption and CO2 production) were measured using a whole-body plethysmography system conjugated with flow controllers and gas analyzer at the acute (1 day post-injury), subchronic (2 weeks post-injury), and chronic (8 weeks post-injury) injury stages. The results demonstrated that mid-cervical contusion caused a significant reduction in the tidal volume. Although the tidal volume of contused animals can gradually recover, it remains lower than that of uninjured animals at the chronic injury stage. While O2 consumption and CO2 production were similar between uninjured and contused animals at the acute injury stage, these two metabolic parameters were significantly reduced in contused animals at the subchronic to chronic injury stages. Additionally, the relationships between ventilation, metabolism, and body temperature were altered by cervical spinal cord injury. These results suggest that cervical spinal cord injury causes a complicated reconfiguration of ventilation and metabolism that may enable injured animals to maintain a suitable homeostasis for adapting to the pathophysiological consequences of injury.

scholarly journals Mild Acute Intermittent Hypoxia Improves Respiratory Function in Unanesthetized Rats With Midcervical Contusion

2016 ◽  
Vol 31 (4) ◽  
pp. 364-375 ◽  
Author(s):  
Kun-Ze Lee ◽  
Shu-Chi Chiang ◽  
Yu-Jie Li
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Tidal Volume ◽  
Respiratory Function ◽  
Intermittent Hypoxia ◽  
Differential Forms ◽  
Male Rats ◽  
Whole Body ◽  
Sham Surgery ◽  
Cord Injury

Background. Mild intermittent hypoxia has been considered a potential approach to induce respiratory neuroplasticity. Objective. The purpose of the present study was to investigate whether mild acute intermittent hypoxia can improve breathing function in a clinically relevant spinal cord injury animal model. Methods. Adult male rats received laminectomy or unilateral contusion at the C3-C4 spinal cord using a MASCIS Impactor (height: 6.25 or 12.5 mm). At 4 weeks postinjury, the breathing patterns of unanesthetized rats were measured by whole body plethysmography before, during and after 10 episodes of 5 minutes of hypoxia (10% O2, 4% CO2, balance N2) with 5 minutes of normoxia intervals. Results. The results demonstrated that cervical contusion resulted in reduction in breathing capacity and number of phrenic motoneurons. Acute hypoxia induced significant increases in frequency and tidal volume in sham surgery and contused animals. In addition, there was a progressive decline in the magnitude of hypoxic ventilatory response during intermittent hypoxia. Further, the tidal volume was significantly enhanced in contused but not sham surgery rats at 15 and 30 minutes postintermittent hypoxia, suggesting intermittent hypoxia can bring about long-term facilitation of tidal volume following cervical spinal contusion. Conclusions. These results suggest that mild acute intermittent hypoxia can elicit differential forms of respiratory plasticity in sham surgery versus contused animals, and may be a promising neurorehabilitation approach to improve respiratory function after cervical spinal cord injury.

Effects of serotonergic agents on respiratory recovery after cervical spinal injury

2015 ◽  
Vol 119 (10) ◽  
pp. 1075-1087 ◽  
Author(s):  
Shih-Hui Hsu ◽  
Kun-Ze Lee
Keyword(s):  
Spinal Cord ◽  
Tidal Volume ◽  
Spinal Injury ◽  
Cervical Spinal Cord ◽  
Serotonergic System ◽  
Chronic Injury ◽  
Adult Rats ◽  
Respiratory Impairment ◽  
Cord Injury ◽  
Cervical Spinal Injury

Unilateral cervical spinal cord hemisection (i.e., C2Hx) usually interrupts the bulbospinal respiratory pathways and results in respiratory impairment. It has been demonstrated that activation of the serotonin system can promote locomotor recovery after spinal cord injury. The present study was designed to investigate whether serotonergic activation can improve respiratory function during the chronic injury state. Bilateral diaphragm electromyogram and tidal volume were measured in anesthetized and spontaneously breathing adult rats at 8 wk post-C2Hx or C2laminectomy. A bolus intravenous injection of a serotonin precursor [5-hydroxytryptophan (5-HTP), 10 mg/kg], a serotonin reuptake inhibitor (fluoxetine, 10 mg/kg), or a potent agonist for serotonin 2A receptors (TCB-2, 0.05 mg/kg) was used to activate the serotonergic system. Present results demonstrated that 5-HTP and TCB-2, but not fluoxetine, significantly increased the inspiratory activity of the diaphragm electromyogram ipsilateral to the lesion for at least 30 min in C2Hx animals, but not in animals that received sham surgery. However, the tidal volume was not increased after administration of 5-HTP or TCB-2, indicating that the enhancement of ipsilateral diaphragm activity is not associated with improvement of the tidal volume. These results suggest that exogenous activation of the serotonergic system can specifically enhance the ipsilateral diaphragmatic motor outputs, but this approach may not be sufficient to improve respiratory functional recovery following chronic cervical spinal injury.

Rehabilitation of the canine patient following spinal cord injury: a practical guide

2021 ◽  
Vol 26 (1) ◽  
pp. 1-6
Author(s):  
Cheryl Corral
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Spinal Injury ◽  
Neurological Deficits ◽  
Practical Guide ◽  
Cord Injury ◽  
Physical Therapies

This article forms part of a series exploring the rehabilitation of the canine shoulder, elbow, back, hip and stifle following injury or disease. Discussed here are different rehabilitation techniques used to address neurological deficits, pain and weakness following spinal injury, including physical therapies, electrotherapies and acupuncture.

Sign in / Sign up

Export Citation Format

Share Document