Optogenetic Model Advances Limb Spasticity Research

Researchers at the University of Ottawa have made significant strides in understanding limb spasticity following spinal cord injury (SCI) by developing an innovative optogenetic mouse model. This groundbreaking research is detailed in their study titled An optogenetic mouse model of hindlimb spasticity after spinal cord injury, published in the journal Experimental Neurology.

The Significance of Spasticity

Spasticity is a neurological condition characterized by involuntary and sustained muscle contractions. It affects approximately two-thirds of Canadians with spinal cord injuries and can greatly impair movement and quality of life. The current study builds upon previous research limitations, offering an improved method for studying spasticity, which could accelerate the discovery of effective treatments.

Innovative Research Methodology

The research team successfully created a transgenic mouse model that enables activation of specific hind limb nerves through light. According to Tuan Bui, the Chair and Professor in the Department of Biology at uOttawa, this model allows researchers to reliably activate the sensory pathways thought to contribute to spasticity, providing a controlled approach to inducing the condition.

“By utilizing optogenetics, we were able to activate specific sensory pathways with light, allowing us to induce spasticity in a controlled manner,” Bui explained. This method addresses inconsistency issues found in prior experimental techniques.

Research Contributions

The study conducted at the Motor Circuits Laboratory involved a collaborative effort from:

• Sara Goltash, Ph.D. graduate
• Riham Khodr, honors undergraduate student
• Alex Laliberte, postdoctoral fellow

This collaboration underscores the university's commitment to advancing neuroscience and rehabilitation research.

Key Findings

One of the pivotal discoveries of the research is that spasticity can commence as early as two weeks after spinal cord injury. This critical period opens the possibility for early intervention strategies. Additionally, understanding the differences between sexes in spasticity responses may lead to more targeted therapies in the future.

Statistical Validity

The study's findings were backed by rigorous statistical analysis, with significance determined by the Mann-Whitney test. Researchers identified specific expression patterns in certain proteins that correlate with spasticity, as seen in analyses of:

Implications for Future Research

The implications of this research are far-reaching. As Alex Laliberte notes, “Our new animal model could significantly facilitate the study and discovery of new therapeutics for the complications of spasticity.” This model not only enhances the understanding of spasticity but also provides a reliable experimental platform for the development of future treatments.

“Understanding the differences between sexes in spasticity responses could also lead to more targeted treatments in the future.” – Alex Laliberte

Conclusion

The evolution of this optogenetic mouse model marks a turning point in the study of limb spasticity, providing a pathway toward more targeted and effective therapies for individuals suffering from spinal cord injury complications. As the need for innovative treatments grows, this research offers hope for improving the quality of life for millions impacted by spasticity worldwide.

More Information: Sara Goltash et al, An optogenetic mouse model of hindlimb spasticity after spinal cord injury, Experimental Neurology (2025).

References

• Goltash, S., Khodr, R., & Laliberte, A. (2025). An optogenetic mouse model of hindlimb spasticity after spinal cord injury. Experimental Neurology.