[Effect of human hair keratin implant on oligodendrocyte proliferation and differentiation in rats with acute spinal cord injury].
OBJECTIVE
To investigate the changes of oligodendrocyte proliferation and differentiation in response to implantation of degradable human hair keratin (HHK) into the spinal cord with acute injury in adult rats.


METHODS
Rat models of acute spinal cord injury were established by direct impact of the exposed spinal cord with a weight-dropping device, 12 of which received immediate HHK implant into the injured spinal cord. The rats of control injury group (n=12) were subjected to the injury but did not receive subsequent implant, and those in sham operation group (n=12) only had the spinal cord exposure without injury. Another 8 rats were used as the normal control group. Samples of the spinal cord were obtained 1, 4, 12, and 26 weeks respectively after the operations and serial sections were prepared for examination with light and electron microscope.


RESULTS
One week after the injury, few oligodendrocytes were observed among the large number of the infiltrating leukocytes in the injured spinal cord with HHK implants. Staining with hematoxylin eosin and Mallory's phosphotungstic acid-hematoxylin at the fourth week revealed oligodendrocyte proliferation around the HHK implant. The period from the 12th to 26th week was characterized by nerve regeneration and myelin sheath reconstruction, in the course of which empty cavity occurred within the sheath of the oligodendrocytes, and lamellar separation of the myelin sheath were observed. Phagocytized myelin sheath and axone fragment were detected in oligodendrocytes, with the newly generated oligodendrocytes scattering abound the rebuilt myelin sheath.


CONCLUSIONS
HHK can be beneficial for the proliferation and differentiation of oligodendrocytes and myelin sheath rebuilding and repair in the course of neuronal regeneration after acute spinal cord injury.
Xu
Xi-jin
XJ
Department of Anatomy, First Military Medical University, Guangzhou 510515, China. xuxijin1960@sohu.com
Piao
Ying-jie
YJ
Huo
Xia
X
D000818:Animals; D002454:Cell Differentiation; D002455:Cell Division; D005260:Female; D006197:Hair / Q000378:metabolism; D006801:Humans; D007633:Keratins / Q000008:administration & dosage*; D009416:Nerve Regeneration; D009836:Oligodendroglia / Q000502:physiology*; D019736:Prostheses and Implants; D051381:Rats; D017207:Rats, Sprague-Dawley; D013119:Spinal Cord Injuries / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*
D007633:Keratins