The experimental study of 5-lipoxygenase expression after spinal cord ischemia in rats

Objective To study the expression of 5-lipoxygenase(5-LOX) in spinal cord ischemia.Methods Ischemia model was set up by ligation of five lumber arteries below the left renal artery. Fifty Male Sprague Dawley rats were randomly allocated into the following groups: sham group (n=10), groups separately subjected to 6h (n=10), 12h (n=10), 24h (n=10), 48h (n=10) of spinal cord ischemia. They were evaluated by tarlov hind limb locomotor rating scale and HE staining. The expressions of 5-LOX were detected by immunohistochemistry and RT-polymerase chain reaction (RT-PCR)in lumber spinal cord specimens.Results Tarlov hind limb locomotor rating scale showed that values of all animals from sham group were 4 and none of them was completely paralyzed. Compared with sham group, 8 animals from group subjected to 48h of spinal cord ischemia were completely paralyzed and tarlov values of the other 2 animals were 1. HE staining showed that the shape and structure of neuron was normal in animals from sham group. But hemorrhage, significant neuron necrosis and myelomalacia was observed in animals from groups subjected to 24h and 48h of spinal cord ischemia. Immunohistochemistry showed that sham group expressed low level of 5-LOX. The expression of 5-LOX was significantly higher in experiment groups than in sham group and increased with prolongation of ischemia time (P0.01). RT-PCR showed that sham group contains low level of 5-LOX mRNA mRNA. The content of 5-LOX mRNA was significantly higher in experiment groups than in sham group and increased with prolongation of ischemia time (P0.01). Conclusion 5-LOX involved in the inflammatory after spinal cord ischemia and caused great damage. It can be used as a Potential therapy target to attenuate spinal cord ischemia injury.