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Free keywords:
NOGO-A; FUNCTIONAL RECOVERY; TRANSGENIC MICE; ANTIBODY IN-1;
ASTROCYTES; PROTEIN; LESION; BRAIN; DEGENERATION; FIBERSBiochemistry & Molecular Biology; Cell Biology; Medicine, Research &
Experimental;
Abstract:
Studying regeneration in the central nervous system (CNS) is hampered
by current histological and imaging techniques because they provide
only partial information about axonal and glial reactions. Here we
developed a tetrahydrofuranbased clearing procedure that renders fixed
and unsectioned adult CNS tissue transparent and fully penetrable for
optical imaging. In large spinal cord segments, we imaged fluorescently
labeled cells by `ultramicroscopy' and two-photon microscopy without
the need for histological sectioning. We found that more than a year
after injury growth-competent axons regenerated abundantly through the
injury site. A few growth-incompetent axons could also regenerate when
they bypassed the lesion. Moreover, we accurately determined
quantitative changes of glial cells after spinal cord injury. Thus,
clearing CNS tissue enables an unambiguous evaluation of axon
regeneration and glial reactions. Our clearing procedure also renders
other organs transparent, which makes this approach useful for a large
number of preclinical paradigms.
