一种C-Jun N-末端激酶肽抑制剂在沙土鼠全脑缺血中的保护作用

目的 为了进一步研究海马C1区域神经细胞活动中JNK的作用，我们评价了一种JNK抑制剂即D-JNKI1在沙土鼠一过性大脑缺血模型中对迟发性神经细胞死亡（DND）的作用。方法 55只沙土鼠随机分为11个组。5组沙土鼠先接受5min前脑缺血处理，再灌注3h后，通过立体定向方法。向每组沙土鼠右侧侧脑室内分别注入不同浓度的D-JNKI1（2μL PBS内加入0．00012，0．0012，0．012，0．12，1．2μmol／L D-JNKI1，每组n=5）。对照组（n=5）：沙土鼠先接受5min前脑缺血处理，再灌注3h后，通过立体定向方法方法向右侧侧脑室内仅注入PBS2μL。腹腔内注射组（n=5）沙土鼠；先接受5min前脑缺血处理，再灌注3h后，1．2μmol／L D-JNKI1溶于0．5mL PBS腹腔内注射。假手术组（n=5）；沙土鼠仅暴露双侧颈总动脉，未夹闭。预处理组（共3组，n=15）：先将0．0012μmol／L D-JNKI1，0．00012μmol／L D-JNKI1溶于2μL PBS，分别注入两组沙土鼠的右侧侧脑室内，另外一组沙土鼠的右侧侧脑室内仅仅注入PBS2μL，30min后三组均夹闭双侧颈总动脉2min，48h后再次接受双侧颈总动脉夹闭5min。所有沙土鼠从接受夹闭5min双侧颈总动脉后4d处死，作冰冻切片和Niss1染色。结果 缺血再灌注3h后用D-JNKI-1治疗，有神经保护作用，最好的神经保护效应浓度为0．0012μmol／L。D-JNKI-1预处理加强了2min预处理所诱导的缺血耐受效应。结论D-JNKI1在沙土鼠全脑缺血模型中对海马CA1区域的迟发性神经细胞死亡有潜在的神经保护作用。

Neuroprotective effect of a peptide inhibitor of c-Jun N-terminal kinase on global cerebral ischemia in gerbils

Objective To assess the effect of D-JNKI1, an inhibitor of c-Jun N-terminal kinase (JNK), on delayed neuronal death (DND) in a gerbil model of transient global cerebral ischemia, so as to further study the roles of JNK activation in mediating neuronal cell death in brain ischemia. Methods Fifty-five Mongolian gerbils were randomly divided into 11 groups. Animals (n=35) assigned into 7 groups (n=5 per group) were subjected to 5-min occlusion of bilateral common carotid arteries (BCCAO);among the 7 groups, different doses of D-JNKI1 (0.00012, 0.0012, 0.012, 0.12, 1.2 μmol/L in 2 μL PBS,n=5 each) were administered stereotaxically into right lateral ventricles 3 h after reperfusion; the control group (n=5) received 2 μL PBS; and another group (n=5) received 1.2 μmol/L of D-JNKI1 in 0.5 mL PBS intraperitoneally. Sham-operated animals (n=5) only received the exposure of bilateral common carotid arteries without occlusion. Three groups (n=5 in each) were pretreated with D-JNKI1 (0.00012,0.0012 μmol/L in 2 μL PBS) or only 2 μL PBS 30 min before 2-min BCCAO, and subjected to 5-min BCCAO 48 h after the first ischemic insult. All animals were sacrificed 4 d after 5-min BCCAO and prepared for frozen section and Nissl staining. Results The treatment with D-JNKI 3 h after 5-min ischemia was neuroprotective with a maximum effect at a dose of 0.0012 μmol/L. Pretreatment with D-JNKI augmented ischemic tolerance induced by 2-min ischemia. Conclusion D-JNKI1 has a potential neuroprotective effect on DND in CA1 of hippocampus in gerbils with global cerebral ischemia-reperfusion injury.