丁基苯酞对慢性脑缺血大鼠学习记忆能力及前脑组织线粒体Na+-K+-ATP酶的影响

目的 探讨丁基苯酞对慢性脑缺血大鼠学习记忆能力以及前脑组织线粒体Na+-K+-ATP酶的影响.方法 将实验用SD大鼠随机分为假手术组(n=10)、模型组(n=15)、丁基苯酞大剂量治疗组(n=15)和小剂量治疗组(n=15).采用双侧颈总动脉结扎制作慢性脑缺血模型,4周后,分别给模型组、大、小剂量丁基苯酞组大鼠腹腔注射生理盐水、丁基苯酞6 mg/kg和2 mg/kg,2次/d.用药4周后,利用Morris水迷宫试验测试大鼠学习记忆能力,提取前脑组织线粒体,测定线粒体Na+-K+-ATP酶的活性.结果 较假手术组相比,模型组大鼠记忆能力明显下降,逃避潜伏期延长[分别为(10.41±3.81)s和(25.54±9.82)s,P＜0.01]线粒体ATP酶活力下降[分别为(3.73±0.32)μmol·mgprot-1·h-1和(2.81±0.40)μmol·mgprot-1·h-1,P＜0.05],而丁基苯酞大、小剂量组较模型组记忆能力显著增强[分别为(11.72±5.78)s和(12.48±5.45)s,P＜0.01],ATP酶活力明显增加[分别为(3.53±0.37)μmol·mgprot-1·h-1和(3.43±0.43)μmol·mgprot-1·h-1,P＜0.05],不同剂量丁基苯酞组差异无显著性(P＞0.05).结论 丁基苯酞注射液可增强缺血区神经元线粒体Na+-K+-ATP酶活力,改善线粒体能量代谢,提高慢性脑缺血大鼠的学习记忆能力.     

慢性脑低灌注大鼠海马神经元损伤的机制研究

目的 探究慢性脑低灌注大鼠海马神经元损伤的机制.方法 双侧颈总动脉结扎(2VO)制备慢性脑低灌注大鼠模型,2VO术后8周取材,分别进行HE染色、电镜、流式细胞术以及Western Blotting检测.结果 HE结果显示2VO组的海马神经元排列稍紊乱,且数量与假手术对照相比有不同程度减少[CA2区:(34.75±3.40)个,(49.25±9.67)个,P＜0.05;DG区:(73.50±9.26)个,(90.75±4.35)个,P＜0.05];电镜观察发现2VO组大鼠海马区部分神经元胞核中略有固缩,出现异染色质边集,胞浆则出现水肿,以线粒体与内质网尤甚;流式细胞术结果表明2VO组海马神经元早期凋亡率[(9.117±2.540)%]高于假手术对照组[(4.750±3.481)%],差异有统计学意义(P＜0.05);Western Blotting检测发现procaspase-3在2VO组大鼠海马的表达与假手术对照组差异无显著性(P＞0.05).结论 慢性脑低灌注大鼠海马神经元的损伤主要由凋亡造成.

Abstract：

Objective To explore the the cellular damage of hippocampus neuron in a rat model of chronic cerebral hypoperfusion. Methods Rat model of chronic cerebral hypoperfusion was established by permanent bilateral common carotid arteries occlusion (2VO). Eight weeks after the operation,the brains were removed and examined with histological stains, electron microscope, flow cytometer and Western Blotting. Results Compared with the control group,the arrangement of hippocampus neurons in 2VO rats appeared to be more irregular, and the number of the neurons decreased partly ( CA2: ( 34.75 ± 3.40) vs (49.25 ± 9.67 ), P ＜ 0. 05; DG: ( 73.50 ± 9.26)vs ( 90.75 ± 4.35 ), P ＜ 0. 05 ). By electron microscopic study of hippocampus neurons in 2VO rats, the nuclei became smaller and the heterochromatin assembled in the border of the nuclei in some neurons, while cytoplasm swelled,especially in mitochondria and endoplasmic reticulum. The rate of apoptosis of hippocampus neurons in 2VO rats( (9. 117 ±2. 540)% ) ,detected by the flow cytometer,was higher than that of sham group( (4. 750 ±3.481 ) % ) (P ＜ 0. 05 ). The expression of pro-caspase-3 in hippocampus of 2 VO rats was not altered significantly compared with the control group(P ＞ 0. 05 ). Conclusion The cellular damage of hippocampus neuron in 2VO rats was mainly caused by apoptosis.     

Patent ductus arteriosus and cerebral,cardiac, and gut hemodynamics in premature neonates

Patent ductus arteriosus is associated with multiple comorbidities in premature infants, however a causal link or strategy to decrease these morbidities has not been found. The association between the patent ductus arteriosus and morbidities has biologic plausibility as, like any cardiac mixing lesion, a significant systemic to pulmonic shunt may lead to pulmonary over-circulation and systemic hypoperfusion. Understanding the underlying pathophysiology of associated morbidities in the setting of a patent ductus arteriosus may aid in risk stratifying infants and offer a patient targeted approach to infants with a pathological ductal shunt. While the deleterious impact of increased pulmonary blood flow maybe easier to identify, the impact on end-organ perfusion is more challenging. In this review, we will discuss the pathophysiology of a hemodynamically significant patent ductus arteriosus in premature infants, impact on end-organ perfusion and associated morbidities, and novel modalities to assess shunt volume and effect on end-organ perfusion.     

慢性脑低灌注性血管性认知损害患者血清p75神经营养素受体细胞外段水平及其与炎性因子的关系

目的 检测慢性脑低灌注性血管性认知损害（CCH-VCI）患者血清p75神经营养素受体细胞外段（p75NTR-ECD）水平,并探讨其与肿瘤坏死因子α（TNF-α）、白细胞介素（IL）-1β、IL-6的关系。方法 选择海军军医大学（第二军医大学）长海医院2018年8月至12月收治的34例CCH-VCI患者,以及同期相同年龄段的36名中老年健康人和34例缺血性脑卒中患者作为研究对象。采用酶联免疫吸附试验测定3组研究对象的血清p75NTR-ECD、TNF-α、IL-1β、IL-6水平并进行组间比较。采用Spearman相关分析研究CCH-VCI患者血清p75NTR-ECD水平与TNF-α、IL-1β、IL-6水平的相关性。结果 CCH-VCI组血清p75NTR-ECD水平高于健康对照组和缺血性脑卒中组[（544.36（440.88,628.50）pg/mL vs 276.49（262.59,313.87）pg/mL、366.87（337.09,450.43）pg/mL],差异均有统计学意义（U=87.500、335.500,P均<0.05）。CCH-VCI组患者血清TNF-α、IL-1β、IL-6水平分别为196.02（141.20,280.35）pg/mL、68.23（60.79,91.94）pg/mL、51.04（40.24,65.26）pg/mL,缺血性脑卒中组分别为218.67（143.76,281.28）pg/mL、76.87（59.10,99.91）pg/mL、64.45（43.13,86.76）pg/mL,均分别高于健康对照组[分别为73.71（56.94,79.81）pg/mL、42.98（34.52,51.34）pg/mL、14.97（11.76,21.19）pg/mL],差异均有统计学意义（U=31.000、4.000,106.000、132.000,48.000、13.000;P均<0.05）。CCH-VCI患者血清p75NTR-ECD水平与TNF-α水平存在相关性（r=0.391,P=0.022）,但与IL-1β和IL-6水平均无明显相关性（r=0.032、0.164,P=0.855、0.355）。结论 慢性脑低灌注损伤后p75NTR可能与TNF-α等炎性因子有关,并共同参与了CCH-VCI的发病。     

加减薯蓣丸抑制单磷酸腺苷活化蛋白激酶活性对慢性脑灌注不足大鼠的神经保护研究

目的 检测慢性脑灌注不足大鼠海马组织单磷酸腺苷活化蛋白激酶（adenosine monophosphate-activated protein kinase, AMPK）水平的变化,探讨加减薯蓣丸对海马神经细胞损伤的影响及其作用机制。方法 采用改良双侧颈总动脉阻断法复制慢性脑灌注不足模型,应用尼氏染色检测神经细胞损伤情况,应用Western blot法检测海马区AMPK及p-AMPK表达水平。结果 与正常组比较,模型组大鼠海马CA1区的尼氏染色较浅,神经锥体细胞数减少,海马组织p-AMPK表达水平明显升高（P<0.05）;与模型组比较,中药组与西药组大鼠海马CA1区的尼氏染色加深,锥体细胞数量增加,p-AMPK表达水平明显下降（P<0.05）;中药组与西药组大鼠海马CA1区AMPK和p-AMPK表达水平比较,差异均无统计学意义（P>0.05）。结论 大鼠慢性脑灌注不足损伤后,AMPK过度激活,出现海马神经细胞损伤,加减薯蓣丸可抑制海马区AMPK的激活,减轻海马神经损伤。     

老龄大鼠慢性脑灌注不足脑内星形细胞的活动

目的：探讨星形细胞在慢性脑灌注不足脑损害中的作用。方法：７０只老龄大鼠持久性双侧颈总动脉结扎（２ＶＯ）,其中１２只接受环孢霉素Ａ（ＣｓＡ）胃灌治疗。免疫组化法多克隆抗血清ＧＦＡＰ标记星形细胞。实验研究为持久性２ＶＯ１～４月。结果：持久性２ＶＯ１月皮层、海马和白质处的星形细胞明显增生、肥大。１～４月,皮层、海马和白质处星形细胞继续增生、肥大、同时脑损害加重,ＣｓＡ治疗后脑损害明显减轻,星形细胞的活性     

Permanent cerebral hypoperfusion: ‘preconditioning-like' effects on rat energy metabolism towards acute systemic hypotension

Chronic cerebrovascular disorders are often complicated by additional temporary ischaemic insults, resulting in substantial deterioration of brain energy metabolism. In the present study, chronic limitations of oxygen supply were induced in Wistar rats by 2 weeks of permanent bilateral common carotid artery occlusion (2-vo) to initiate a ‘preconditioning-like' effect that protects rat brain energy metabolism against further acute systemic hypotension (15 min). Haemodynamic parameters, arterial blood gases and body temperature were monitored. Energy metabolites were determined in rat parietotemporal cerebral cortex: adenosine 5′-triphosphate (ATP), adenosine 5′-diphosphate (ADP), adenosine 5′-monophosphate (AMP), phosphocreatine (PCr), and adenosine by the high-pressure liquid chromatography (HPLC) technique and lactate spectrophotometrically. After 2 weeks, permanent 2-vo led to a significant decrease in the concentrations of cortical tissue ATP and PCr, from 3.06±0.48 to 2.09±0.28 and from 4.27±0.63 to 3.35±0.41 μmol/g, respectively. These changes were associated with a two-fold increase in AMP and adenosine. Acute systemic hypotension alone (non-preconditioning) reduced ATP and PCr drastically, to 0.97±0.51 and 1.76±1.23 μmol/g. Tissue concentrations of lactate, AMP, and adenosine were markedly increased, three- to five-fold, in ‘non-preconditioned' brain tissue. In contrast, after 2 weeks of 2-vo acute hypotension did not significantly alter the cortical energy state any further. The effects of preconditioning on tissue ATP and PCr were most pronounced at 5 min and 48 h after reperfusion. In conclusion, permanent 2-vo seems to activate compensatory mechanisms, which effectively protect the rat's cortical energy metabolism against an additional ischaemic attack (‘preconditioning-like' effect).     

急性等容血液稀释及联合降压对犬胃肠灌注的影响

目的 观察急性等容血液稀释联合硝普钠控制性降压对犬胃肠灌注的影响。方法 健康杂种犬16只,随机分为血液稀释组和联合组。以6％羟乙基淀粉等量置换全血实施急性等容血液稀释(ANH),分别使Het降至20％～25％(HD1)、10％～15％(HD2);控制性降压期间,0．02％硝普钠溶液泵人,使MAP降至50mmHg维持30min。监测各稀释水平以及稀释联合降压时的血液动力学和胃粘膜二氧化碳分压(PgCO2)的变化。结果 (1)血液稀释组HD1及HD2时CO、SI显著增高,SVRI、PVRI显著降低(P＜0．01),MAP、HR、CVP、PAP、PCWP不变;(2)血液稀释组HDl及HD2时Hb、CaO2、CvO2、DO2显著降低(P＜0．01),而ERO2增高,VO2不变;(3)与基础值比,联合组CO、SI、MAP、SVRI、PVRI显著降低(P＜0．01);(4)血液稀释组PgCO2、胃粘膜与呼气末二氧化碳分压差(KETCO2)无显著变化;联合组PgCO2、Pg-ET CO2分别由48．6mmHg、9．8mmHg增高至70．7mmHg、29．3mmHg。结论 血液稀释联合硝普钠降压时,因静脉回心血量下降,心输出量因而降低,内脏灌注受损。