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THE PROTECTIVE EFFECT OF NEUREGULIN-1 TO THE OLIGODENDROCYTE PROGENITOR CELLS AFTER ACUTE INJURY OF THE SPINAL CORD
Ruixi Li, Huiting Liu, Yan Sun, Ruihe Lin, Ying Liu and Yuwen Peng
Department of Anatomy, Histology and Embryology, Shanghai Medical College, Fudan University, Shanghai 200032, China
Neuregulin-1 (NRG-1) is a growth factor secreted mainly by neurons and glial cells. It plays an important role not only in
regulating the survival, proliferation and differentiation of the oligodendrocyte lineage but also in neuroprotection after ischemic
brain damage. In order to understand the protective effect of Neuregulin-1 (NRG-1) to the oligodendrocyte progenitor cells
(OPCs), which generate the oligodendrocytes, after acute injury of the spinal cord, the expressions of the NRG-1 in the normal
and injured spinal cord and the cultured OPCs of the rat were comparatively examined by the immunohistochemical and western
blot methods. The results showed that 1) the NRG-1 inmmunoreactivity was extensively distributed throughout the white and gray
matters in the normal spinal cord, 2) the expression of the NRG-1 was increased from the first day after an acute spinal cord
injury, got to a peak which was double higher than that in the control in the second day, then decreased gradually from the third
day after the injury, 3) the NRG-1 and its receptor ErbB4 were expressed basically in normal cultured OPCs, 4) the expression of
NRG-1 in cultured OPCs decreased immediately after hypoxia within 2 h, and dramatically increased to reach the highest level at
4 h after reoxygenation, then downregulated again continuously till to the level that is hardly detected at 24h after reoxygenation,
5) the rate of apoptosis of OPCs and the expression of TNF-α were effectively reduced after the administration of NRG-1in the
cultured OPCs. These results suggest that the abundant NRG-1 in the spinal cord may play important role in neuroprotection by
protecting the OPCs from apoptosis and inflammatory reaction after exposure to hypoxia in the injury of the spinal cord.
Fig. 1 Expression of the NRG-1 in
gray matter of the spinal cord
Fig. 2 Expression of the NRG-1 in
white matter of the spinal cord
Fig. 3 Expression of the NRG-1 in the
spinal cord after an acute injury
Fig. 5 Expression of the receptors of the NRG-1
in the cultured OPCs
Fig. 4
Expression of
the NRG-1 in
cultured OPCs
Neurosphere for OPC
Fig. 6 Expression of NRG-1 in cultured
OPCs after hypoxia
Fig. 7
Rate of apoptosis of
OPCs after the
administration of NRG-1