环孢霉素A对大鼠脊髓损伤早期环氧化酶-2与肿瘤坏死因子α表达的影响

Effect of cyclosporine A on the expression of cycloxygenase-2 and tumor necrosis factor-α in early stage of spinal cord injury in rat

中文关键词:  脊髓损伤  环孢霉素A  环氧化酶-2  肿瘤坏死因子-α  大鼠

英文关键词:Spinal cord injury  Cyclosporin A  Cycloxygenase-2  Tumor necrosis factor-α  Rat

中文摘要:

  【摘要】　目的：观察环孢霉素A（CsA）对大鼠脊髓损伤（SCI）早期环氧化酶-2（Cox-2）与肿瘤坏死因子α（TNF-α）表达的影响，探讨CsA对大鼠SCI的作用。方法：180只大鼠随机分成对照组、损伤组和损伤后CsA治疗组（治疗组），每组60只。用25g·cm致伤损伤组和治疗组大鼠T8~T11脊髓，对照组不损伤脊髓。治疗组于术后1h予尾静脉注射CsA（2.5mg/kg），之后每隔12h给药1次，对照组和损伤组在相同时间点尾静脉注射相同体积生理盐水。损伤组和治疗组于术后2h、6h、12h、24h、48h和72h处死动物取损伤段脊髓标本，对照组在相应时间点取相应节段脊髓标本，切片后分别行HE染色观察脊髓组织损伤情况、免疫组织化学EnVision法检测TNF-α、免疫组织化学SP法检测Cox-2，并对TNF-α和Cox-2进行定量分析。结果：对照组各时间点脊髓无出血、水肿等变化。损伤组和治疗组伤后2h、6h脊髓灰质可见水肿、出血，但无坏死，周围白质无明显改变；12h、24h脊髓灰质出现广泛灶性出血及出血后形成囊腔，神经元肿胀，部分细胞核浓缩，染色增强，白质见少量红细胞渗出，髓鞘轻度肿胀；48h、72h脊髓灰质中出现神经元固缩、坏死、溶解，细胞体积变小，有大量小胶质细胞增生和中性粒细胞浸润，白质中可见较多红细胞渗出，髓鞘肿胀和大量空泡，周围有炎性细胞浸润和胶质细胞增生；治疗组各时间点的病理改变均较损伤组轻。对照组大鼠脊髓Cox-2呈可疑阳性表达；损伤组和治疗组伤后2h Cox-2即有表达，6h达到高峰，之后逐渐下降；损伤组在伤后72h Cox-2表达仍较对照组高（P<0.05），而治疗组到伤后48h即恢复到对照组水平（P>0.05），治疗组各时间点Cox-2表达均较损伤组低（P<0.05）；对照组大鼠脊髓TNF-α呈可疑阳性或弱阳性表达；损伤组和治疗组伤后2h即有TNF-α表达，12h达到高峰，之后逐渐下降；损伤组在伤后72h TNF-α表达仍较对照组高（P<0.05），而治疗组在伤后72h即恢复到对照组水平（P>0.05），治疗组各时间点TNF-α表达均较损伤组低（P<0.05）。结论：CsA能显著降低大鼠SCI后早期损伤脊髓组织中Cox-2和TNF-α的表达，从而减轻脊髓继发性损伤。

英文摘要:

  【Abstract】 Objective：To investigate the effect of the cyclosporine A（CsA） on the expression of cycloxygenase-2（Cox-2） and tumor necrosis factor-α（TNF-α） in acute spinal cord injury，and the mechanism of CsA on spinal cord injury in rat.Method：180 rats were randomly divided into control group，injury group and the CsA-intervention group with 60 rats in each group.An impact of 2.5g·cm was used to induce spinal cord injury in rat both in injury group and in intervention group.In CsA-intervention group，CsA（2.5mg/kg） was administrated in rats through caudal vein injection 1h after injury，then repeated per 12h after injury，while the control group and injury group received the same dose of normal saline at the same time point.The injured spinal cord segment was collected and processed pathologically at 2h，6h，12h，24h，4h8 and 72h after operation.HE staining and immunohistochemistry staining（TNF-α by the EnVision detection system and Cox-2 by the SP detection system） were performed for every specimen.The expressions of Cox-2 and TNF-α were analyzed quantitatively by HPIAS-2000 high-resolution color graphic pathology report management system.Result：HE staining showed normal of rat spinal cord in control group without bleeding and necrosis.Edema and hemorrhage instead of necrosis in spinal cord gray matter cauld be seen in 2h，6h after injury both in injury group and in intervention group.A wide range of focal hemorrhage and formation of cysts after bleeding occurred in 12h or 24h after injury in spinal cord gray matter.Neurons appeared as swelling，part of nucleus concentrated，HE staining increased，numerous red blood cells and myelin slight swelling were seen in the white matter as well.Neurons appeared pyknosis，necrosis，dissolution in 48h or 72h after injury in the spinal cord gray matter.Microglial cell proliferation and neutrophil infiltration were evidenced in the injured spinal cord.Numerous red blood cells and myelin swelling were seen in the white matter.A great quantity of emptiness，inflammation cell infiltration and microglial cell proliferation were evidenced.Pathological severity at any time point in intervention group was milder than injury group.The expression of Cox-2 remained uncertainty in control group and reached peak at 6h after injury，then decreased.Cox-2 expression in injury group in 72h was higher than control group（P<0.05），while was equal to intervention group in 48h after injury（P> 0.05），Cox-2 expression in intervention group was lower than injury group at each time point（P<0.05）.The expression of TNF-α remained uncertainty in control group.The expression of TNF-α was detected 2h after injury in injury group and the intervention group，which reached peak at 12h after injury，then decreased.The expression of TNF-α in injury group was higher than control group（P<0.05） in 72h after injury.The expression of TNF-α in intervention group resumed to the baseline level of the control group（P>0.05） 72h after injury.TNF-α expression in intervention group was lower than injury group at each time point（P<0.05）.Conclusion：CsA down-regulate the expression of Cox-2 and TNF-α significantly in SCI rats，which can alleviate the secondary spinal cord injury.