Expression patterns of 5-lipoxygenase in human brain with traumatic injury and astrocytoma.
5-Lipoxygenase (5-LOX) is a key enzyme in the metabolism of arachidonic acid to leukotrienes. The levels of leukotrienes increase after brain injury and when tumors are present. It has been reported that 5-LOX is widely expressed in the brain and that 5-LOX inhibition provides neuroprotection. However, there is still no information available for the expression patterns of 5-LOX in human brain following trauma or with astrocytomas. We investigated its expression patterns by immunohistochemistry. We found that 5-LOX is normally expressed in neurons and glial cells. In neurons, it was expressed in two patterns: in the cytosol and nucleus or only in the cytosol. In traumatic brain injury, 5-LOX expression increased in glial cells and neutrophils. Double-labeling immunohistochemistry showed that part of the 5-LOX-positive glial cells were GFAP positive. No 5-LOX expression was found in brain microvessel endothelia, except in the regenerated endothelia of a patient 8 days following brain trauma. Furthermore, 5-LOX expression increased and showed a granular pattern in high-grade (grade III/IV) astrocytoma. These results indicate that 5-LOX has multiple expression patterns, and can be induced by brain injury, which implies that 5-LOX might have pathophysiological roles in the human brain.
Zhang
Lei
L
Department of Pharmacology, the Second Affiliated Hospital, Zhejiang University, Hangzhou, China.
Zhang
Wei-Ping
WP
Hu
Hua
H
Wang
Meng-Ling
ML
Sheng
Wen-Wen
WW
Yao
Hong-Tian
HT
Ding
Wei
W
Chen
Zhong
Z
Wei
Er-Qing
EQ
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001094:Arachidonate 5-Lipoxygenase / Q000096:biosynthesis*; D001254:Astrocytoma / Q000378:metabolism*; D001921:Brain / Q000378:metabolism*; D001930:Brain Injuries / Q000378:metabolism*; D001932:Brain Neoplasms / Q000378:metabolism*; D005260:Female; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009457:Neuroglia / Q000378:metabolism; D009474:Neurons / Q000378:metabolism
D005904:Glial Fibrillary Acidic Protein; D001094:Arachidonate 5-Lipoxygenase