X-irradiation reduces lesion scarring at the contusion site of adult rat spinal cord
S.X. Zhang1, J.W. Geddes2, J.L. Owens1,3 and E.G. Holmberg1,3
1Spinal Cord Society Research Center, Fort Collins, Colorado, USA, 2Spinal Cord and Brain Injury Research Center, University of Kentucky College of Medicine, Lexington, Kentucky, USA and 3University of Alaska Anchorage, Anchorage, Alaska, USA
Offprint requests to: Shu-xin Zhang, M.D., Ph.D., SCS Research Center, 2401 Research Blvd., Suite ·104, Fort Collins, CO, USA. e-mail: firstname.lastname@example.org
Summary. Spinal cord injury (SCI) results in cell death and tissue destruction, and ultimately cavitation followed by the formation of lesion scars at the injury site. The lesion scars include an astrocytic component (glial scar) and a fibroblastic component (connective tissue scar). The purpose of the present study is to determine if X-irradiation could minimize the formation of lesion scars and reduce the levels of chondroitin sulfate proteoglycans (CSPGs) in the contusion SCI model of the adult rat. Two weeks after SCI, a connective tissue scar formed at the injury site consisting primarily of fibroblasts and exhibits strong CSPG immunoreactivity. The fibroblasts might originate from the connective tissue of pia mater or arachnoid mater. At the same time, reactive astrocytes in the spared tissue accumulate surrounding the lesion cavity to form a thick glial scar with significant enhancement of glial fibrillary acidic protein (GFAP) and CSPG immunoreactivity. After X-irradiation (40 Gy) of the injury site 2 days post-injury, that results in an attenuated dose to the lesion, the connective tissue scar was not observed, and accordingly, almost no CSPG immunoreactivity was detected at this area. Meanwhile, the glial scar and its CSPG immunoreactivity were prominently reduced. X-irradiation did not show significant improvement in locomotor recovery, but resulted in a slight delay of body weight recovery following injury. This preparative treatment could be used to reduce secondary scarring in the lesion resulting in an enriched site for further treatment such as growth related transplantation. Histol Histopathol 20, 519-530 (2005).
Key words: X-irradiation, Spinal cord injury (SCI), Lesion scar, Chondroitin sulfate proteoglycans (CSPGs), Glial fibrillary acidic protein (GFAP)