Temporal and segmental distribution of constitutive and inducible nitric oxide synthases after traumatic spinal cord injury: Effect of aminoguanidine treatment
Temporal and segmental distribution of constitutive and inducible nitric oxide synthases after traumatic spinal cord injury: Effect of aminoguanidine treatment
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DOI：
10.1089/089771502753754109
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发表时间：
2002-05-01
影响因子：
4.2
通讯作者：
Dietrich, WD
中科院分区：
文献类型：
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作者：
Chatzipanteli, K;Garcia, R;Dietrich, WD
一氧化氮（NO）在创伤性脑损伤（TBI）和脑缺血的病理生理中起重要作用。然而，其在创伤性脊髓损伤（SCI）发病机制中的作用仍有待阐明。本研究确定了SCI后组成型和诱导型一氧化氮合酶（cNOS和iNOS）的时程。使用NYU撞击器装置在T10对大鼠进行中度SCI，并使其在SCI后存活3、6或24小时和3天（每组n = 5）。为了测定酶活性，将脊髓解剖成五个节段，包括损伤部位的头侧和尾侧（远端）水平。其他大鼠进行灌注固定，用于iNOS蛋白水平的免疫组织化学定位。损伤后3、6 h T10节段cNOS活性显著降低，3、6、24 h吻侧cNOS活性显著降低。(T9)水平（p < 0.05）。伤后3h，损伤区头侧（T8）和尾侧（T11、T12）cNOS活性也明显降低（p < 0.05）。然而，cNOS活性在T8、T11和T12在6 h内恢复到对照水平，在T10和T9节段在1天内恢复到对照水平。iNOS酶活性在测试的所有时间点都升高（p < 0.05），在24小时观察到最强的增加。免疫组化显示，在24小时iNOS蛋白的一个显着的细胞来源似乎是入侵的多形核白细胞（PMNLs）。为了评估iNOS抑制的功能后果，在SCI后5分钟开始氨基胍治疗，并使用BBB旷场运动评分测试大鼠。SCI后7周内，接受治疗的大鼠后肢功能显着改善。组织病理学分析显示，氨基胍治疗后挫伤体积减小37%（P < 0.05）。总之，这些结果表明：（1）cNOS和iNOS活性在中度SCI后受到区域性和时间性影响，（2）PMNL的早期积累是NO诱导的细胞毒性产物的潜在重要来源，（3）急性氨基胍治疗显著改善SCI后的功能和组织病理学结果。
Nitric oxide (NO) has been shown to play an important role in the pathophysiology of traumatic brain injury (TBI) and cerebral ischemia. However, its contribution to the pathogenesis of traumatic spinal cord injury (SCI) remains to be clarified. This study determined the time course of constitutive and inducible nitric oxide synthases (cNOS and iNOS, respectively) after SCI. Rats underwent moderate SCI at T10 using the NYU impactor device and were allowed to survive for 3, 6, or 24 h and 3 days after SCI (n = 5 in each group). For the determination of enzymatic activities, spinal cords were dissected into five segments, including levels rostral and caudal (remote) to the injury site. Other rats were perfusion fixed for the immunohistochemical localization of iNOS protein levels. cNOS activity was significantly decreased at 3 and 6 h within the traumatized T10 segment and at 3, 6, and 24 h at the rostral. (T9) level (p < 0.05). Rostral (T8) and caudal (T11, T12) to the injury site cNOS activity was also decreased at 3 h after injury (p < 0.05). However, cNOS activity returned to control levels within 6 h at T8, T11 and T12 and at one day at T10 and T9 segments. iNOS enzymatic activity was elevated at all time points tested (p < 0.05), with the most robust increase observed at 24 h. Immunostaining for iNOS at 24 h revealed that a significant cellular source of iNOS protein appeared to be invading polymorphonuclear leukocytes (PMNLs). To assess the functional consequences of iNOS inhibition, aminoguanidine treatment was initiated 5 min after SCI and rats tested using the BBB open field locomotor score. Treated rats demonstrated significantly improved hindlimb function up to 7 weeks after SCI. Histopathological analysis of contusion volume showed that aminoguanidine treatment decreased lesion volume by 37% (P < 0.05). In conclusion, these results indicate that (1) cNOS and iNOS activities are regionally and temporally affected after moderate SCI, (2) the early accumulation of PMNLs are a potentially significant source of NO-induced cytotoxic products, and (3) acute aminoguanidine treatment significantly improves functional and histopathological outcome after SCI.