Rapid assessment of internodal myelin integrity in central nervous system tissue.
Monitoring pathology/regeneration in experimental models of de-/remyelination requires an accurate measure not only of functional changes but also of the amount of myelin. We tested whether X-ray diffraction (XRD), which measures periodicity in unfixed myelin, can assess the structural integrity of myelin in fixed tissue. From laboratories involved in spinal cord injury research and in studying the aging primate brain, we solicited "blind" samples and used an electronic detector to record rapidly the diffraction patterns (30 min each pattern) from them. We assessed myelin integrity by measuring its periodicity and relative amount. Fixation of tissue itself introduced +/-10% variation in periodicity and +/-40% variation in relative amount of myelin. For samples having the most native-like periods, the relative amounts of myelin detected allowed distinctions to be made between normal and demyelinating segments, between motor and sensory tracts within the spinal cord, and between aged and young primate CNS. Different periodicities also allowed distinctions to be made between samples from spinal cord and nerve roots and between well-fixed and poorly fixed samples. Our findings suggest that, in addition to evaluating the effectiveness of different fixatives, XRD could also be used as a robust and rapid technique for quantitating the relative amount of myelin among spinal cords and other CNS tissue samples from experimental models of de- and remyelination.
Biology Department, Boston College, Chestnut Hill, Massachusetts, USA. kirschnd@bc.edu
Daniel A
DA
Kirschner
Robin L
RL
Avila
Rodolfo E
RE
Gamez Sazo
Adrienne
A
Luoma
Gaby U
GU
Enzmann
Deepika
D
Agrawal
Hideyo
H
Inouye
Mary Bartlett
MB
Bunge
Jeffery
J
Kocsis
Alan
A
Peters
Scott R
SR
Whittemore
D000375:Aging; D000818:Animals; D002490:Central Nervous System / Q000473:pathology*; D003711:Demyelinating Diseases / Q000139:chemically induced / Q000473:pathology*; D004195:Disease Models, Animal; D004996:Ethidium; D008253:Macaca mulatta; D051379:Mice; D009186:Myelin Sheath / Q000378:metabolism / Q000473:pathology*; D051381:Rats; D014961:X-Ray Diffraction / Q000379:methods
D004996:Ethidium