Quantitative evaluation techniques for syrinx size and functional deficits in a rat model

Background

Syringomyelia (SM) is a neurological disorder that is characterized by the formation of a fluid-filled cyst, a syrinx, inside the spinal cord. SM presents mainly with chronic progressive pain and neurological deficits because syrinxes compress the surrounding neural tissue while expanding, negatively impacting patient quality of life. Research into the molecular aspects of SM, as instructed by animal models, could yield alternative nonsurgical treatment options. However, animal-based studies currently lack quantitative techniques to evaluate syrinx geometry and locomotion deficits to facilitate future research. In this study, the advanced techniques microcomputed tomography (µCT) and Automated Gait Analysis Through Hues and Areas (AGATHA) were implemented in an attempt to better study and quantify syrinx size and locomotion deficits, respectively, in a post-traumatic SM (PTSM) rat model.

Methods

Studies were conducted to implement µCT and AGATHA techniques using an already established PTSM rat model. Syrinx surface area and volume were evaluated in situ after fixing spinal cords 6 weeks after injury using 360o scene via a high-resolution µCT scanner. The locomotion of injured rats was evaluated using AGATHA at -2, 0, 2, 4, 6 weeks post-injury.

Results

The virtual 3D shape of syrinxes (from µCT), as well as locomotion data (from AGATHA), provided quantitative measures of syrinx size and locomotion parameters. The data by µCT analysis were successfully verified by conventional histology. Preliminary findings show the impact of SM on locomotion, and we are working to correlate these data to syrinx measures from µCT.

Discussion and Conclusions

Our data suggest that the µCT technique employed can be used to evaluate syrinx size in terms of surface area and volume as a cost-effective quantitative technique to supplant live animal analyses. Also, our recently reported AGATHA technique for gait analysis following spinal cord injury was successfully implemented to evaluate locomotion deficits due to SM in our rat model.