Development of complete thoracic spinal cord transection model in rats for delayed transplantation of stem cells.
METHODS
In vivo study of a rat spinal cord injury model.


OBJECTIVE
To develop complete transection model of thoracic spinal cord using a polymer sheet and a microtube relevant for delayed transplantation of stem cells.


BACKGROUND
Stem cell transplantation for the regeneration of spinal cord injuries has used animal models. However, current models suffer from inflammation and leakage, which lessens their usefulness in studying delayed stem cell transplantation.


METHODS
Thoracic spinal cord at T9 level of adult Sprague-Dawley rats was exposed and a 50:50 sheet of poly(D,L-lactic-coglycolic acid) was inserted, exposed spinal cord was completely transected, and collagen was filled between the gap between the proximal and distal stumps of transected spinal cord. A microtube was placed and fixed between the polymer surfaces facing each other. Behavior testing, magnetic resonance imaging, and myelography were performed to characterize the new complete transection with a gap formation and polymer insertion (GAP) model and to compare the GAP model with the control models. Human mesenchymal stem cells (hMSCs) were transplanted into 3 models and immunohistochemistry and western blot were performed.


RESULTS
The inserted poly(D,L-lactic-coglycolic acid) sheet was completely disappeared 10 weeks after operation, but the inserted microtube remained firmly fixed in its original position. Myelography of the GAP model showed no leakage of contrast medium around the injured spinal cord, whereas magnetic resonance imaging of the severe contusion and simple transection models showed some leakage of contrast medium. Immunohistochemistry and western blot after hMSCs transplantation indicated that transplanted hMSCs survived and migrated well in the GAP model, and the deposition of inflammatory cells in GAP model was less than a simple transection model or severe contusion model.


CONCLUSIONS
The developed GAP model is more relevant for delayed transplantation of stem cells for the study of regeneration of spinal cord injury of rats.
Department of Orthopaedic Surgery, College of Medicine, Dankook University, Cheonan, Korea.
Sang Hyuk
SH
Min
Sang Hoon
SH
Lee
Hosup
H
Shim
Jeong-Soo
JS
Park
Young Ii
YI
Lee
Hae-Won
HW
Kim
Jung Keun
JK
Hyun
D000818:Animals; D004195:Disease Models, Animal; D019344:Lactic Acid / Q000008:administration & dosage; D011100:Polyglycolic Acid / Q000008:administration & dosage; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D051381:Rats; D017207:Rats, Sprague-Dawley; D013119:Spinal Cord Injuries / Q000473:pathology* / Q000601:surgery*; D033581:Stem Cell Transplantation / Q000379:methods*; D013904:Thoracic Vertebrae / Q000473:pathology / Q000601:surgery; D013997:Time Factors
D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid