The Effect of Keratin on Spinal Cord Injury Recovery
Authors: Zabarsky Zachary , Marquez‐Lara Alejandro , Luo T. David , Van Dyke Mark , Smith Thomas L. 
Published: November 2023

Objective

To evaluate the ability of kertin nanomaterials to create an optimal environment for nerve regeneration and function restoration after spinal cord injury (SCI).

Introduction

Inflammation plays a vital role in the recovery after SCI. Recent studies have shown that macrophage polarization to the M2 anti‐inflammatory phenotype attenuates the inflammatory response, preventing the secondary injury due to inflammation, resulting in improved outcomes following SCI. Keratin nanomaterials may allow for macrophage polarization, therefore we tested the hypothesis that keratin treatments will improve recovery in a rat contusion model of spinal cord injury.

Methods

All aspects of the described protocol were reviewed and approved by the Institutions Animal Care and Use Committee. Female lewis rats were trained and baseline gait recordings were obtained on a DigiGait Imaging System treadmill for two weeks before receiving injury. Blunt SCI was induced with an IH‐0400, Precision Systems and Instrumentation LLC spinal cord impactor following laminectomy at T9 with a consistent force of 150Kdyn, producing a moderate injury with partial recovery. Treatment groups included intrathecal administration of keratin and a saline control. Functional recovery data assessed by the DigiGait were observed at 3 and 6 weeks post‐SCI and compared to pre‐SCI recordings and data.

Results

Gait metrics were analyzed at pre‐SCI and post‐operative (PO) timepoints. Table 1 includes the percent changes from pre‐SCI recordings of gait metrics at 3 and 6 weeks PO for both hind limbs in saline control and keratin treatment groups. Brake duration was decreased in the control rat as compared to the keratin treatment rat. Overlap distance was increased in control rat compared to treatment rat. Paw angel, and swing duration, compared to pre‐operative measures, showed altered ambulation following injury in both groups with varying levels of recovery.

Conclusions

The quantitative data obtained from the DigiGait Imaging system elucidates the altered ambulation following SCI in rats and shows improved scores for the keratin treated group for several parameters. The DigiGait analyzes up to 40 different gait metrics and analysis of additional parameters could show differences between treated groups compared to controls. The keratin treatment seems to be beneficial in some parameters such as brake duration, as longer brake duration may indicate more precise control and distribution of loading during stance phase. Also, more open paw angels of the hind paws are associated with ataxia, spinal cord injury, and demyelinating diseases. Future studies will utilize histological data in addition to gait analysis to document the recovery following SCI in rats and include more keratin treatment delivery methods.

Support or Funding Information

Errett Fisher Foundation

Shows the Percent changes of gait metrics compared to baseline recordings for a non‐treated control rat and a keratin treated rat.

DigiGait Imaging System Gait Analysis of SCI Rats

Metric:
Brake (sec)
Paw angel (deg)
Swing (sec)
Overlap distance (cm)

(Percent Changes compared to Baseline data)

Control

3 weeks L
− 37%
+ 34.7%
− 2.2%
+ 529.6%

3 weeks R
− 37.5%
+ 17.1%
+ 2.5%
+ 181.7%

6 weeks L
− 40.1%
+ 329.9%
+ 8.1%
+ 637.8%

6 weeks R
− 38.5%
+ 7.1%
+ 20.5%
+ 240.6%

Keratin

3 weeks L
− 15%
+ 157.39%
+ 20.4%
+ 92.9%

3 weeks R
+ 9.3%
+ 45.3%
+ 30.3%
+ 65.6%

6 weeks L
− 13.4%
+ 148.7%
+ 2.7%
+ 67.5%

6 weeks R
+ 3.1%
+ 45.9%
+18.8%
+ 193.3%