NgR expression in macrophages promotes nerve regeneration after spinal cord injury in rats.
OBJECTIVE
This study aimed to investigate the expression of Nogo-66 receptor (NgR) in macrophages after SCI and clarify its role in neuron regeneration.


METHODS
Macrophages harvested from injured spine cord of rats were stained by double immunofluorescence labeling technique to observe the expression of NgR at histological and cellular levels. Macrophages which expressed NgR were constructed in vitro, and then the effects of NgR on macrophage phagocytosis and neuraxon regeneration in three groups (NgR-macrophages group, mock group and normal macrophages group) were studied using Western blot, micro-MTT colorimetry, and LDH assay separately.


RESULTS
The results showed that CD68-positive macrophages in injured tissue of spine cord expressed NgR after double immunofluorescence staining on day 7 after SCI, and so did macrophages isolated and cultured from the injured spine cord. The results of Western blot showed that phagocytosis of macrophages in NgR-macrophages group was much better than that in mock group and normal macrophage group (p < 0.05). And the results of Micro-MTT colorimetry and LDH assay indicated that the capacity of neuraxon regeneration in NgR-macrophages group was significantly higher than that in the other two groups (p < 0.05).


CONCLUSIONS
The results suggested that there was NgR expressing in the infiltrated macrophages following SCI, which increased phagocytosis of the macrophages, and promoted post-SCI CNS regeneration in vitro.
Zhu
Zhuangchen
Z
Department of Orthopedics, Changzheng Hospital, The Second Military Medical University, Huangpu District, Shanghai, People's Republic of China. zhuangchenzh@sohu.com
Ni
Bin
B
Yin
Guodong
G
Zhou
Fengjin
F
Liu
Jun
J
Guo
Qunfeng
Q
Guo
Xiang
X
D000818:Animals; D002478:Cells, Cultured; D058851:GPI-Linked Proteins / Q000096:biosynthesis; D008264:Macrophages / Q000378:metabolism*; D008297:Male; D009185:Myelin Proteins / Q000096:biosynthesis*; D009416:Nerve Regeneration; D000070816:Nogo Receptor 1; D051381:Rats; D017207:Rats, Sprague-Dawley; D011956:Receptors, Cell Surface / Q000096:biosynthesis*; D013119:Spinal Cord Injuries / Q000378:metabolism*
D058851:GPI-Linked Proteins; D009185:Myelin Proteins; D000070816:Nogo Receptor 1; D011956:Receptors, Cell Surface; C486581:Rtn4r protein, rat