Training-Induced Functional Gains following SCI

We previously demonstrated that daily, hour-long training sessions significantly improved both locomotor (limb kinematics, gait, and hindlimb flexor-extensor bursting patterns) and nonlocomotor (bladder function and at-level mechanical allodynia) functions following a moderate contusive spinal cord injury. The amount of training needed to achieve this recovery is unknown. Furthermore, whether this recovery is induced primarily by neuronal activity below the lesion or other aspects related to general exercise is unclear. Therefore, the current study objectives were to (1) test the efficacy of 30 minutes of step training for recovery following a clinically relevant contusion injury in male Wistar rats and (2) test the efficacy of training without hindlimb engagement. The results indicate that as little as 30 minutes of step training six days per week enhances overground locomotion in male rats with contusive spinal cord injury but does not alter allodynia or bladder function. Thirty minutes of forelimb-only exercise did not alter locomotion, allodynia, or bladder function, and neither training protocol altered the amount of in-cage activity. Taken together, locomotor improvements were facilitated by hindlimb step training for 30 minutes, but longer durations of training are required to affect nonlocomotor systems.

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Spinal Cord Injury Causes Reduction of Galanin and Gastrin Releasing Peptide mRNA Expression in the Spinal Ejaculation Generator of Male Rats

Frontiers in Neurology ◽

10.3389/fneur.2021.670536 ◽

2021 ◽

Vol 12 ◽

Author(s):

James W. Wiggins ◽

Jonathan E. Sledd ◽

Lique M. Coolen

Keyword(s):

Spinal Cord ◽

Spinal Cord Injury ◽

Male Rats ◽

Lumbar Spinal Cord ◽

Gastrin Releasing Peptide ◽

Cord Injury ◽

Contusion Injury ◽

Spinal Contusion ◽

Lumbar Spinal ◽

Injury Causes

Spinal cord injury (SCI) in men is commonly associated with sexual dysfunction, including anejaculation, and chronic mid-thoracic contusion injury in male rats also impairs ejaculatory reflexes. Ejaculation is controlled by a spinal ejaculation generator consisting of a population of lumbar spinothalamic (LSt) neurons that control ejaculation through release of four neuropeptides including galanin and gastrin releasing peptide (GRP) onto lumbar and sacral autonomic and motor nuclei. It was recently demonstrated that spinal contusion injury in male rats caused reduction of GRP-immunoreactivity, but not galanin-immunoreactivity in LSt cells, indicative of reduced GRP peptide levels, but inconclusive results for galanin. The current study further tests the hypothesis that contusion injury causes a disruption of GRP and galanin mRNA in LSt cells. Male rats received mid-thoracic contusion injury and galanin and GRP mRNA were visualized 8 weeks later in the lumbar spinal cord using fluorescent in situ hybridization. Spinal cord injury significantly reduced GRP and galanin mRNA in LSt cells. Galanin expression was higher in LSt cells compared to GRP. However, expression of the two transcripts were positively correlated in LSt cells in both sham and SCI animals, suggesting that expression for the two neuropeptides may be co-regulated. Immunofluorescent visualization of galanin and GRP peptides demonstrated a significant reduction in GRP-immunoreactivity, but not galanin in LSt cells, confirming the previous observations. In conclusion, SCI reduced GRP and galanin expression in LSt cells with an apparent greater impact on GRP peptide levels. GRP and galanin are both essential for triggering ejaculation and thus such reduction may contribute to ejaculatory dysfunction following SCI in rats.

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A Simple and Cost-Effective Weight Drop Model to Induce Contusive Spinal Cord Injury: Functional and Histological Outcomes

Archives of Neuroscience ◽

10.5812/ans.118775 ◽

2021 ◽

Vol In Press (In Press) ◽

Author(s):

Shiva Hashemizadeh ◽

Saereh Hoseindoost ◽

Khalil Pestei ◽

Mahmoudreza Hadjighassem

Keyword(s):

Spinal Cord ◽

Spinal Cord Injury ◽

Cost Effective ◽

Sensory Function ◽

Therapeutic Interventions ◽

Cord Injury ◽

Male Wistar Rats ◽

Weight Drop ◽

Contusive Spinal Cord Injury ◽

Hind Limb Paralysis

Background: Animal spinal cord injury (SCI) models have provided a better perception of the mechanisms related to traumatic SCI and evaluation of the effectiveness of experimental therapeutic interventions. Objectives: The aim of this study is to develop a cost-effective modified Allen's device to induce contusive spinal cord injury. Methods: Adult male Wistar rats were subjected to contusive spinal cord injury using a customized weight drop model through 10-g weights delivered from a 25-mm height onto an exposed spinal cord. Locomotor and sensory function during 28 days were assessed. Moreover, histopathological changes were assessed at one week and 28 days post SCI. Results: All the SCI rats showed hind limb paralysis up to 48 h post SCI and neuropathic pain after injury. Histological changes similar to the previous reports for contusion model were observed. Conclusions: According to our findings, little variability was observed in the BBB score of individual rats at 28 days after injury. Our customized device to induce spinal cord injury is a simple and inexpensive alternative method to the highly sophisticated contusion device commonly used to induce SCI.

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