Methods for behavioral testing of spinal cord injured rats

Bancroft

2017

Journal of Neurotrauma

Opioids are frequently used for the treatment of pain following spinal cord injury (SCI). Unfortunately, we have shown that morphine administered in the acute phase of SCI results in significant, adverse secondary consequences including compromised locomotor and sensory recovery. Similarly, we showed that selective activation of the j-opioid receptor (KOR), even at a dose 32-fold lower than morphine, is sufficient to attenuate recovery of locomotor function. In the current study, we tested whether activation of the KOR is necessary to produce morphine's adverse effects using norBinaltorphimine (norBNI), a selective KOR antagonist. Rats received a moderate spinal contusion (T12) and 24 h later, baseline locomotor function and nociceptive reactivity were assessed. Rats were then administered norBNI (0, 0.02, 0.08, or 0.32 lmol) followed by morphine (0 or 0.32 lmol). Nociception was reassessed 30 min after drug treatment, and recovery was evaluated for 21 days. The effects of norBNI on morphine-induced attenuation of recovery were dose dependent. At higher doses, norBNI blocked the adverse effects of morphine on locomotor recovery, but analgesia was also significantly decreased. Conversely, at low doses, analgesia was maintained, but the adverse effects on recovery persisted. A moderate dose of norBNI, however, adequately protected against morphine's adverse effects without eliminating its analgesic efficacy. This suggests that activation of the KOR system plays a significant role in the morphineinduced attenuation of recovery. Our research suggests that morphine, and other opioid analgesics, may be contraindicated for the SCI population. Blocking KOR activity may be a viable strategy for improving the safety of clinical opioid use.

Section: Assessments Of Sensory Reactivitymentioning

confidence: 99%

Section: Assessments Of Sensory Reactivitymentioning

confidence: 99%

Section: Locomotor Recoverymentioning

confidence: 99%

Section: Locomotor Recoverymentioning

confidence: 99%

Section: Locomotor Recoverymentioning

confidence: 99%

See 3 more Smart Citations

Nor-Binaltorphimine Blocks the Adverse Effects of Morphine after Spinal Cord Injury

Bancroft

2017

Journal of Neurotrauma

European Journal of Pain

Effects of astaxanthin on sensory‐motor function in a compression model of spinal cord injury: Involvement ofERKandAKTsignalling pathway

Fakhri

Dargahi

Abbaszadeh

et al. 2018

Background Spinal cord injury (SCI) causes continuous neurological deficits and major sensory‐motor impairments. There is no effective treatment to enhance sensory‐motor function following SCI. Thus, it is crucial to develop novel therapeutics for this particular patient population. Astaxanthin (AST) is a strong antioxidant, anti‐inflammatory and anti‐apoptotic agent. In the present study, it was tested in a severe compression SCI model with emphasis on sensory‐motor outcomes, signalling pathway, along with other complications. Methods A severe SCI was induced by compression of the rat thoracic spinal cord with an aneurysm clip and treatment with AST or the vehicle was carried out, 30 min after injury. Behavioural tests including open field, von Frey, hot plate and BBB were performed weekly to 28 days post‐injury. Rats were assigned to measure blood glucose, weight and auricle temperature. Western blot and histological analysis also were performed at the same time points. Results AST decreased mechanical and thermal pain and also improved motor function performance, reduced blood glucose and auricle temperature increases and attenuated weight loss in SCI rats. Western blot analysis showed decreased activation of ERK1/2 and increased activation of AKT following AST treatment. The histology results revealed that AST considerably preserved myelinated white matter and the number of motor neurons following SCI. Conclusion Taken together, the beneficial effects of AST to improve sensory‐motor outcomes, attenuate pathological tissue damage and modulate ERK and AKT signalling pathways following SCI, suggest it as a strong therapeutic agent towards clinical applications. Significance Spinal cord injury (SCI) impairs sensory‐motor function and causes complications, which astaxanthin (AST) has the potential to be used as a treatment for. The present study investigates the effects of AST in a compression model of SCI with emphasis on sensory‐motor outcomes alongside other complications, histopathological damage and also related signalling pathways.

Journal of Biophotonics

Effects of photobiomodulation in experimental spinal cord injury models: A systematic review

Tobelem

Silva

Araujo

et al. 2022

This systematic review investigated the repercussions of photobiomodulation using lowlevel laser therapy (LLLT) for the treatment of spinal cord injury (SCI) in experimental models. Studies were identified from relevant databases published between January 2009 and December 2021. Nineteen original articles were selected and 68.4% used light at an infrared wavelength. There was a considerable variation of the power used (from 25 to 200 mW), total application time (8-3000 s) and total energy (0.3-450 J). In 79% of the studies, irradiation was initiated immediately after or within 2 h of the SCI, and treatment time ranged continuously from 5 to 21 days. In conclusion, LLLT can be an auxiliary therapy in the treatment of SCI, playing a neuroprotective role, enabling functional recovery, increasing the concentration of nerve connections around the injury site and reducing pro-inflammatory cytokines. However, there is a need for standardization in the dosimetric parameters.