Neural transplantation in the spinal cord with traumatized gray matter: Integration and connections of the transplants
Abstract
This project examined the growth and anatomical integration of embryonic neural tissues transplanted in lesion cavities in the spinal cords of adult rats. A central hemorrhagic lesion was produced by dissecting out the gray matter from the adult cord to result in a cavity, into which fifteen-days old embryonic neocortical, brainstem or spinal cord tissues were transplanted and allowed to survive and grow for 2.5 to 3 months. The cord was then subjected to a second lesion, rostral or caudal to the transplant, to sever any descending or ascending fibers that might have given off afferents or collaterals to the transplants. Histological analysis using Cresyl Violet, Thionin, Bodian's protargol and Fink-Heimer stains was performed to determine the final volumes of the transplants, and the source and extent of the ingrowth of the afferents. The interactions between host pathological reactions and the transplants were also analyzed. Experimental animals were compared to controls to determine whether the transplants had any ameliorative properties on the paraplegia like syndrome produced by this kind of lesion. Analysis revealed that neocortical tissues had the highest growth potential when compared to brainstem or spinal cord tissues. The afferent connectivity achieved by the transplants was low to moderate in intensity and was mainly restricted to the zone of interface between the transplant and the host cord. There was no evidence to indicate that afferents traversed the length of the transplant to reach the cord on the opposite side. The pathological responses in the host cord were exaggerated in the presence of brainstem and spinal cord transplants. With neocortical transplants, these responses showed a very limited expression. Behavioral observations demonstrated the role of spared ventral funiculi in animals with thoracic lesions in spontaneous recovery from paraplegia. Sparing of motor neurons in animals with lumbar lesions was also essential to prevent paraplegia. Embryonic neural transplants had no ameliorative properties under these conditions of spinal trauma.
Degree
Ph.D.
Advisors
Das, Purdue University.
Subject Area
Neurology
Off-Campus Purdue Users:
To access this dissertation, please log in to our
proxy server.