TIME-RELATED CHANGES IN MYELOPEROXIDASE ACTIVITY AND LEUKOTRIENE B-4 RECEPTOR-BINDING REFLECT LEUKOCYTE INFLUX IN CEREBRAL FOCAL STROKE
TIME-RELATED CHANGES IN MYELOPEROXIDASE ACTIVITY AND LEUKOTRIENE B-4 RECEPTOR-BINDING REFLECT LEUKOCYTE INFLUX IN CEREBRAL FOCAL STROKE
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DOI：
10.1007/bf03160109
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发表时间：
1995-01-01
期刊：
影响因子：
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通讯作者：
SARAU, HM
中科院分区：
文献类型：
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作者：
BARONE, FC;HILLEGASS, LM;SARAU, HM
在之前的研究中，我们已经使用组织学方法来表征细胞变化，并验证了髓过氧化物酶（MPO）活性测定在缺血性卒中中定量增加的中性粒细胞浸润的使用。我们还发现白三烯B-4 （LTB(4)）结合位点的增加是中性粒细胞浸润局灶性缺血组织的潜在标志。然而，这些研究仅在缺血后24小时的一个时间点进行。在本研究中，我们检测了自发性高血压大鼠永久性（PMCAO）或暂时性（再灌注后160分钟）大脑中动脉闭塞（MCAO）后MPO活性和LTB(4)受体结合的全时间过程，并将结果与这些模型中先前表征的组织学变化进行了比较。检测缺血和对侧（对照）皮质组织样本的MPO （U/g wet wt）和[H-3]LTB(4)受体结合（fmol/mg蛋白）。PMCAO处理后，MPO活性最早在12 h显著升高，并在随后的5 d内持续升高（p < 0.05）。经TMCAO处理后，MPO活性仅在再灌注6 h后就显著升高，并在再灌注5 d后继续升高（p < 0.05）。LTB(4)受体结合与MPO活性在两者同时升高期间高度相关（即0.5-5 d; p < 0.01）。然而，在mcao后15 d， MPO活性水平恢复正常后，LTB(4)受体结合仍然升高。这种持续的LTB(4)结合与先前在这些模型中持续存在的显著胶质瘤有关。mcao后MPO活性增加和LTB(4)结合最初增加的时间过程与我们之前描述这些条件下白细胞浸润时间过程的组织学数据非常吻合。因此，随着时间的推移，MPO活性的增加与这些模型中最初的中性粒细胞和后来的单核细胞浸润到缺血组织有关。此外，本研究利用组织化学分析证实了MCAO后脑梗死内巨噬细胞的过氧化物酶活性，从而证实了MPO活性来源于后期浸润的单个核细胞，以及之前以相同方式表征的早期浸润的中性粒细胞。与PMCAO治疗相比，TMCAO在缺血皮质MPO活性的早期显著增加和后期MPO活性的类似增加。显然，缺血后脑组织的再灌注大大加重了脑组织的炎症程度。这些生化分析，特别是MPO活性分析，现已被证实可用于定量组织损伤的早期和晚期脑炎症反应。
In previous studies, we have used histological methods to characterize cellular changes, and validated the use of the myeloperoxidase (MPO) activity assay to quantitate increased neutrophil infiltration in ischemic stroke. We also identified increased leukotriene B-4 (LTB(4)) binding sites as a potential marker for neutrophil infiltration into focal ischemic tissue. However, these studies were conducted at only one time-point, 24 h after ischemia. In the present study, we examined the full time-course of MPO activity and LTB(4) receptor binding following middle cerebral artery occlusion (MCAO) made permanently (PMCAO) or transiently (160 min followed by reperfusion; TMCAO) in spontaneously hypertensive rats, and compared the results to previously characterized histologic changes in these models. Ischemic and contralateral (control) cortical tissue samples were assayed for MPO (U/g wet wt) and [H-3]LTB(4) receptor binding (fmol/mg protein). Following PMCAO, MPO activity significantly increased as early as 12 h and continued to increase over the next 5 d (p < 0.05). Following TMCAO, MPO activity was significantly elevated already after only 6 h of reperfusion and also continued to increase over the next 5 d of reperfusion (p < 0.05). LTB(4) receptor binding and MPO activity were highly correlated during periods when both measures increased together (i.e., 0.5-5 d; p < 0.01). However, by 15 d post-MCAO, LTB(4) receptor binding remained elevated after MPO activity levels had returned to normal. This persistent LTB(4) binding was associated with the significant gliosis that was characterized previously to persist in these models. The time-course of increased MPO activity and initially increased LTB(4) binding post-MCAO correspond very well to our previous histological data that characterized the time-course for leukocyte infiltration under these conditions. Therefore, the increased MPO activity over time was associated with initial neutrophil and later mononuclear cell infiltration into ischemic tissue in these models. In addition, the present studies utilized histochemical analysis to demonstrate peroxidase activity in macrophages within the cerebral infarct following MCAO, thus validating that MPO activity originates from the later infiltrating mononuclear cells in addition to the early infiltrating neutrophils that had been previously characterized in the same manner. TMCAO produces a significantly larger and earlier increase in ischemic cortex MPO activity and a similar later increase in MPO activity compared to PMCAO treatment. Clearly, reperfusion of cerebral tissue following ischemia greatly exacerbates the degree of cerebral tissue inflammation. These biochemical assays, especially the MPO activity assay, have now been validated for quantitating the early and late phases of the cerebral inflammatory reaction to tissue injury.