5-脂氧合酶在大鼠脊髓缺血组织中表达的实验研究

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

目的研究5-脂氧合酶(5-LOX)在大鼠不同缺血时间点脊髓组织中的表达特点。方法50只雄性SD大鼠随机分成5组,假手术组及缺血6、12、24、48h组。采用阻断左肾下5条腰动脉的方法建立大鼠脊髓缺血模型,运用改良的Tarlov评分和HE染色的方法对脊髓模型进行评价;免疫组化染色,RT-PCR方法检测大鼠脊髓组织中5-LOX的表达。结果Tarlov评分:假手术组10只大鼠均为4分,无一发生瘫痪,缺血48h组2只为1分,余8只完全瘫痪;HE染色:假手术组神经细胞外形清楚、结构正常,缺血24、48h组出现大量神经元坏死,组织中有灶性出血,可见脊髓组织软化;免疫组化染色评分(H-score法):5-LOX正常脊髓组织低表达,缺血6、12、24、48h组表达高于假手术组并呈递增趋势(P<0.01);RT-PCR检测:5-LOXmRNA在正常脊髓组织表达低,在缺血6、12、24、48h脊髓组织表达高于假手术组并呈递增趋势(P<0.01)。结论5-LOX参与了脊髓缺血继发性的炎症反应,可作为治疗脊髓缺血的重要靶点。

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 Tartov 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 （P〈0.01）. 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 （P〈0.01）. 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.