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Updated: Aug 1, 2025
Dorsal Root Ganglion Injection and Dorsal Root Crush Injury as a Model for Sensory Axon Regeneration
Published on: May 3, 2017
Riluzole treatment modulates KCC2 and EAAT-2 receptor expression and Ca2+ accumulation following ventral root
Krisztián Pajer1, Tamás Bellák1, Tímea Grósz2
1Department of Anatomy, Histology and Embryology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary.
Abstract:
Avulsion injury results in motoneuron death due to the increased excitotoxicity developing in the affected spinal segments. This study focused on possible short and long term molecular and receptor expression alterations which are thought to be linked to the excitotoxic events in the ventral horn with or without the anti-excitotoxic riluzole treatment. In our experimental model the left lumbar 4 and 5 (L4, 5) ventral roots of the spinal cord were avulsed. Treated animals received riluzole for 2 weeks. Riluzole is a compound that acts to block voltage-activated Na+ and Ca2+ channels. In control animals the L4, 5 ventral roots were avulsed without riluzole treatment. Expression of astrocytic EAAT-2 and that of KCC2 in motoneurons on the affected side of the L4 spinal segment were detected after the injury by confocal and dSTORM imaging, intracellular Ca2+ levels in motoneurons were quantified by electron microscopy. The KCC2 labeling in the lateral and ventrolateral parts of the L4 ventral horn was weaker compared with the medial part of L4 ventral horn in both groups. Riluzole treatment dramatically enhanced motoneuron survival but was not able to prevent the down-regulation of KCC2 expression in injured motoneurons. In contrast, riluzole successfully obviated the increase of intracellular calcium level and the decrease of EAAT-2 expression in astrocytes compared with untreated injured animals. We conclude that KCC2 may not be an essential component for survival of injured motoneurons and riluzole is able to modulate the intracellular level of calcium and expression of EAAT-2.
Insights
Riluzole treatment enhanced motoneuron survival after spinal root avulsion by reducing excitotoxicity. It prevented increased intracellular calcium and decreased EAAT-2 expression, but not KCC2 downregulation.
Area of Science:
- Neuroscience
- Spinal Cord Injury Research
- Neuroprotection
Background:
- Avulsion injuries lead to motoneuron death via excitotoxicity in spinal cord segments.
- Understanding molecular changes, including receptor expression, is crucial for developing treatments.
- Riluzole, a neuroprotective agent, blocks voltage-activated Na+ and Ca2+ channels.
Purpose of the Study:
- To investigate short and long-term molecular and receptor expression alterations linked to excitotoxicity after spinal root avulsion.
- To evaluate the effects of riluzole treatment on these changes and motoneuron survival.
Main Methods:
- Avulsion of L4, 5 ventral roots in an experimental model.
- Riluzole administration for 2 weeks in treated animals.
- Confocal and dSTORM imaging to detect EAAT-2 and KCC2 expression.
- Electron microscopy to quantify intracellular Ca2+ levels.
Main Results:
- Riluzole significantly enhanced motoneuron survival.
- KCC2 expression was downregulated in injured motoneurons, irrespective of riluzole treatment.
- Riluzole prevented the rise in intracellular calcium and the decrease in astrocytic EAAT-2 expression.
Conclusions:
- KCC2 downregulation may not be essential for injured motoneuron survival.
- Riluzole effectively modulates intracellular calcium levels and EAAT-2 expression in astrocytes.
- Riluzole demonstrates significant neuroprotective effects against excitotoxicity in spinal avulsion injuries.
