Leger Pierre-Louis, Pansiot Julien, Besson Valerie, Palmier Bruno, Renolleau Sylvain, Baud Olivier, Cauli Bruno, Charriaut-Marlangue Christiane
From the PROTECT, INSERM, University Paris Diderot, France (P.-L.L., J.P., V.B., O.B., C.C.-M.); UPMC, AP-HP, Hôpital Armand Trousseau, PICU, Paris, France (P.-L.L.); Pharmacologie de la Circulation Cérébrale-EA4475, University Paris Descartes, Faculté de Pharmacie, France (V.B., B.P.); University Rene Descartes, AP-HP, Hôpital Necker, PICU, Paris, France (S.R.); Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Neurosciences Paris Seine-Institut de Biologie Paris Seine (NPS-IBPS), Paris, France (B.C.).
Stroke. 2016 Dec;47(12):3048-3052. doi: 10.1161/STROKEAHA.116.015095. Epub 2016 Nov 10.
We previously showed that the selective neuronal nitric oxide synthase inhibitor 7-nitroindazole (7-NI) increases cerebral microcirculation in a juvenile ischemic rat model. We address the roles of cyclooxygenase (COX)-elaborated prostaglandins in collateral recruitment and blood supply.
Fourteen-day-old rats were subjected to ischemia-reperfusion and treated with either PBS or 7-NI (25 mg/kg) at the reperfusion onset. Six-keto-prostaglandin F was measured using ELISA. COX-1 and COX-2 and prostaglandin terminal synthesizing enzymes were evaluated using reverse-transcriptase polymerase chain reaction and immunofluorescence. Microvascular blood flow indexes (artery diameter and capillaries number) were measured using sidestream dark-field videomicroscopy in PBS- and 7-NI-treated ischemic rats in the absence or presence of the COX-2 inhibitor NS-398 (5 mg/kg). Cell death was measured with the TUNEL (terminal transferase dUTP nick end labeling) assay and cleaved-caspase-3 immunostaining.
Six-keto-prostaglandin F and COX-2, associated with a prostaglandin E synthase, were significantly increased in PBS- and 7-NI-treated animals 15 minutes and 1 hour after ischemia-reperfusion, respectively. In contrast and as compared with PBS, 7-NI significantly decreased prostacyclin synthase and cytosolic prostaglandins E synthase mRNA. Selective COX-2 inhibition significantly decreased blood flow indexes and significantly reversed the effects of 7-NI, including the number of TUNEL- and cleaved-caspase-3-nuclei.
These results show that the juvenile rat brains mostly respond to ischemia by a COX-2-dependent prostaglandins production and suggest that the transcriptional responses observed under 7-NI facilitate and reorient COX-2-dependent prostaglandins production.
我们之前的研究表明，选择性神经元型一氧化氮合酶抑制剂7-硝基吲唑（7-NI）可增加幼年缺血大鼠模型的脑微循环。我们探讨环氧化酶（COX）产生的前列腺素在侧支循环募集和血液供应中的作用。
14日龄大鼠接受缺血再灌注，并在再灌注开始时用PBS或7-NI（25mg/kg）进行治疗。使用酶联免疫吸附测定法测量6-酮-前列腺素F。使用逆转录聚合酶链反应和免疫荧光评估COX-1、COX-2和前列腺素末端合成酶。在不存在或存在COX-2抑制剂NS-398（5mg/kg）的情况下，使用侧流暗视野视频显微镜测量PBS和7-NI处理的缺血大鼠的微血管血流指数（动脉直径和毛细血管数量）。用末端脱氧核苷酸转移酶介导的dUTP缺口末端标记（TUNEL）法和裂解的半胱天冬酶-3免疫染色测量细胞死亡。
在缺血再灌注后15分钟和1小时，与前列腺素E合酶相关的6-酮-前列腺素F和COX-2在PBS和7-NI处理的动物中分别显著增加。相比之下，与PBS相比，7-NI显著降低前列环素合酶和细胞溶质前列腺素E合酶mRNA。选择性COX-2抑制显著降低血流指数，并显著逆转7-NI的作用，包括TUNEL和裂解的半胱天冬酶-3阳性细胞核的数量。
这些结果表明，幼年大鼠大脑对缺血的反应主要是通过COX-2依赖性前列腺素的产生，并表明在7-NI作用下观察到的转录反应促进并重新定向COX-2依赖性前列腺素的产生。
