The role of inducible nitric oxide synthase following spinal cord injury in rat.
Acute spinal cord injury (SCI) is two-step process that first involves the primary mechanical injury and then the secondary injury is induced by various biochemical reactions. Apoptosis is one of secondary SCI mechanisms and it is thought to play an important role for the delayed neuronal injury. The enhanced formation of nitric oxide (NO) via inducible nitric oxide synthase (iNOS) has been implicated in the pathogenesis of apoptosis in SCI. The level of .iNOS mRNA peaked at 6 hr after SCI and it declined until 72 hr after SCI in a rat model. Double-immunofluorescence staining revealed that iNOS positive cells were stained for ED-1, synaptophysin, GFAP, and oligodendrocyte marker. The terminal deoxynucleotidyl-transferase-mediated dUDP-biotin nick end-labeling (TUNEL) positive cell count was higher for the 72 hr post-SCI group than for the 24 hr post-SCI group. This cell count was also higher going in the caudal direction than in the rostral direction from the epicenter, and especially for the 72 hr group. Treatment with a selective iNOS inhibitor resulted in the reduction of TUNEL-positive cells at the lesion site. These findings suggest that nitric oxide generated by the iNOS of macrophages, neurons, oligodentrocytes, and astrocytes plays an important role for the acute secondary SCI that results from apoptotic cell death.
Kwak
Eun Kyoung
EK
Department of Oral Pathology, School of Medicine, Kyungpook National University, Daegu, Korea.
Kim
Jung Wan
JW
Kang
Ku Seong
KS
Lee
Yoon Hee
YH
Hua
Quan Hong
QH
Park
Tae In
TI
Park
Ji Young
JY
Sohn
Yoon Kyung
YK
D000704:Analysis of Variance; D000818:Animals; D017209:Apoptosis; D005904:Glial Fibrillary Acidic Protein / Q000032:analysis; D020287:In Situ Nick-End Labeling; D008856:Microscopy, Fluorescence; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013116:Spinal Cord / Q000737:chemistry / Q000201:enzymology / Q000473:pathology; D013119:Spinal Cord Injuries / Q000201:enzymology* / Q000473:pathology / Q000503:physiopathology; D013997:Time Factors
D005904:Glial Fibrillary Acidic Protein; D012333:RNA, Messenger