Expression and location of 15-lipoxygenase in hypoxic rat brain

Aim: To confirm the relation between 15-hydroxyeicosatetraenoic acid (15-HETE) and cerebral hypoxia through studying the expressions and location of 15-lipoxygenase(15-OL) in hypoxic rat brain for further inverstigating the mechanism of hypoxia-induced dysfunction of central nervous system. Methods: The study was finished in the Educational Base and Pathological Laboratory Department of Harbin Medical University between January and December 2002. Twelve Wistar rats were randomly divided into two groups: control group raised in normal environment (FiO₂, 210 mL/L) and hypoxic group raised in hypoxic box containing mixed gas of nitrogen gas and oxygen(90: 10, 100 mL/L). After 9 days, the rats were killed under anesthesia and the brains were taken out and sliced into frozen sections. Then in situ hybridization and immunohistochemistry staining were performed. Results: There were little positive cells expressing 15-LO mRNA and protein in the control group, but positive cells which expressed 15-LO mRNA and protein in the hypoxic group were significantly increased(P < 0.01). 15-LO mRNA was mainly expressed in hippocampus, vascular endothelial cells, smooth muscle cells, choroid and neuronal nuclei, and little in cytoplasm and neuroglial cells. While 15-LO protein was mainly found in the cytoplasm of endothelial cells and smooth muscle cells, hippocampus, little in choroids and neuroglial cells, but not in neurons. Conclusion: Hypoxia can improve the expression of 15-LO in brain that is involved in the hypoxia-induced brain injury.