Clark R S, Kochanek P M, Schwarz M A, Schiding J K, Turner D S, Chen M, Carlos T M, Watkins S C
Department of Anesthesiology and Critical Care Medicine, Safar Center for Resuscitation Research, Pittsburgh, Pennsylvania 15260, USA.
Pediatr Res. 1996 May;39(5):784-90. doi: 10.1203/00006450-199605000-00007.
The inflammatory response after traumatic brain injury (TBI) includes cytokine production, leukocyte infiltration, and microglial activation. Production of nitric oxide by inducible nitric oxide synthase (iNOS) occurs during acute inflammation outside of the CNS and in models of cerebral ischemia, and therefore may contribute to the inflammatory response after TBI. The purpose of this study was to localize and define the time course of iNOS expression after TBI in the immature rat. Immature Wistar rats (age 3.5-4.5 wk) were anesthetized and subjected to percussive trauma to the right parietal cortex. Nontraumatized rats were used as controls (n = 7). At 2, 24, 48, or 168 h (n = 3/group) posttrauma rats were killed by perfusion fixation. Brains were removed, frozen, sectioned, immunostained with antibodies against iNOS and glial fibrillary acidic protein (GFAP, a marker specific for astrocytes), and imaged using fluorescent detection systems. There was no detectable expression of iNOS in control brains. At 2h, minimal cerebrovascular iNOS expression was seen in the peritrauma area. At 24 and 48 h, there was marked peritrauma cerebrovascular iNOS expression that appeared to be restricted to vascular smooth muscle cells and infiltrated leukocytes. Further dual-immunolabeling showed that the leukocytes expressing iNOS were predominantly neutrophils. At 168 h, iNOS expression was no longer detectable. iNOS was not detectable in GFAP-positive cells. The prominent expression of iNOS protein after TBI in cerebrovascular smooth muscle cells and infiltrated neutrophils suggests that iNOS may play a role in cerebrovascular disturbances and secondary brain injury after trauma.
创伤性脑损伤（TBI）后的炎症反应包括细胞因子产生、白细胞浸润和小胶质细胞激活。诱导型一氧化氮合酶（iNOS）产生一氧化氮发生在中枢神经系统外的急性炎症期间以及脑缺血模型中，因此可能促成TBI后的炎症反应。本研究的目的是在未成熟大鼠中定位并确定TBI后iNOS表达的时间进程。将未成熟的Wistar大鼠（3.5 - 4.5周龄）麻醉，对其右顶叶皮质进行撞击伤。未受伤的大鼠用作对照（n = 7）。在创伤后2、24、48或168小时（每组n = 3），通过灌注固定处死大鼠。取出大脑，冷冻，切片，用抗iNOS和胶质纤维酸性蛋白（GFAP，星形胶质细胞特异性标志物）的抗体进行免疫染色，并使用荧光检测系统成像。对照大脑中未检测到iNOS的表达。在2小时时，在创伤周围区域可见最小程度的脑血管iNOS表达。在24和48小时时，创伤周围脑血管有明显的iNOS表达，似乎局限于血管平滑肌细胞和浸润的白细胞。进一步的双重免疫标记显示，表达iNOS的白细胞主要是中性粒细胞。在168小时时，不再能检测到iNOS表达。在GFAP阳性细胞中未检测到iNOS。TBI后脑血管平滑肌细胞和浸润的中性粒细胞中iNOS蛋白的显著表达表明，iNOS可能在创伤后脑血管紊乱和继发性脑损伤中起作用。
