Expression of neurocan mRNA and ultrastructure of brain tissue after cerebral ischemia and reperfusion in stroke-prone renovascular hypertensive rats treated by electroacupuncture

We established a stroke-prone renovascular hypertensive rat model by bilateral constriction of the renal artery with sliver loop clips. After ten weeks, middle cerebral artery occlusion was induced for 2 hours. The rats then received electro-acupuncture at Baihui （DU 20） and Dazhui （DU 14） after onset of ischemia for 30 days. In situ hybridization study showed that electroacupuncture significantly reduced the number of neurocan mRNA-positive cells in the ischemic penumbra and hippocampal tissues of rats. Electron microscopy results demonstrated that the structure of neurons and blood vessels in the ischemic tissues were restored with electroacupuncture. Overall, these data suggest that electroacupuncture may protect neurons against ischemic reperfusion injury in stroke-prone renovascular hypertensive rats, which may be regulated by downregulation of expression of nerve inhibitory factor neurocan mRNA.

Effect of 2-Selenium Bridged β-Cyclodextrin,Glutathione Peroxidase Mimic on Stroke of Stroke-prone Spontaneously Hypertensive Rats

To investigate the treatment effect of 2-selenium bridged β -cyclodextrin(2-SeCD),a GPX mimic,on the stroke of stroke-prone spontaneously hypertensive rats(SHRSP),fifty-two SHRSP of 8-week old were randomly divided into four groups A,B,C and control group D. The rats of groups A,B,C and D were given 1.0%-1.5% NaCl mass fraction as drinking fluid. After onset of stroke,groups A,B and C were given \{orally\} 16.05,160.5 and 1605 mg·kg -1 ·day -1 of 2-SeCD,respectively,and group D was given water for \{2 weeks.\} The clinical score of stroke,systolic blood pressure(SBP),survival time of rats were recorded and the histopathologic examinations of their brain and carotid artery were made after decapitation. The clinical scores of stroke after treatment with 160.5 mg·kg -1 ·day -1 (Group B) and 1605 mg·kg -1 ·day -1 (Group C) of 2-SeCD are 2.55±0.98 and 1.98±0.79,respectively,those are obviously lower than that of group D(3.41±0.83,p<0.01). The survival days in group B(10.0±8.6) and group C(14.4±7.9) are longer than that for group D(4.7±2.9,p<0.01). The electron microscope study showed that the endothelium of carotid artery was near to normal in group B and group C,while it was seriously injured in control group D and mildly injured in group A. 2-SeCD may effectively be used to treat the stroke for SHRSP.

Protective Effects of Nobiletin on Hypertension and Cerebral Thrombosis in Stroke-Prone Spontaneously Hypertensive Rats (SHRSP)

Some citrus flavonoids have been reported to possess antioxidant activities that moderate endothelial dysfunction and show protective effects on cardiovascular disease. We have investigated the protective effects of nobiletin (5,6,7,8,3’,4’-hexamethoxy flavone) derived from the peel of Citrus depressa Hayata (Shiikuwasha), a citrus fruit produced in Okinawa prefecture in Japan on hypertension and thrombogenicity in cerebral vessels of stroke-prone spontaneously hypertensive rats (SHRSP). Nobiletin was added to the diet of male SHRSP (7 weeks old) for 4 weeks. The age-related increase in systolic blood pressure usually observed in SHRSP was significantly suppressed in the treated animals. Thrombogenesis in pial blood vessels, determined using a He-Ne laser technique, and antioxidant activity, assessed by measuring urinary 8-hydroxy-2’-deoxyguanosine (8-OHdG), were significantly reduced after treatment. Urinary nitric oxide (NO) metabolites and acetylcholine-induced endothelial relaxation were increased after dietary intervention. These results strongly suggested that antihypertensive and antithrombotic effects of nobiletin may be related to an increase in bioavailable NO, possibly mediated by the scavenging of reactive oxygen species (ROS).

POTENT HYPOTENSIVE EFFECTS OF ORPHANIN FQ IN CONSCIOUS STROKE-PRONE SPONTANEOUSLY HYPERTENSIVE RATS

Orphanin FQ（OFQ） or nociceptin is a novel neuropeptide consisting of 17 amino acids. This peptide has a primary structure reminiscent of that of opioid peptide but exhibits an opposite effect to make animals hyperreactive. The effect of this new peptide on cardiovascular function are not completely known. The present study was conducted to investigate the effect of intravenous bolus injection of orphanin FQ on mean arterial blood presure （MABP） in conscious stroke-prone spontaneously hypertensive rats (SHRsp). Adult male SHRsp and Wistar normotensive rats （250～300 g body weight, 2. 5～3 months old） were used in this study. The MABP was measured in the conscious state by a tail-cuff method. In SHRsp model, intravenous bolus injection of orphanin FQ or Tyr1-orphanin FQ （0. 5 mg/kg） induced a prolonged and marked reduc- tion in MABP. The maximum changes in MABP were -30. 2±4. 2 mmHg by orphanin FQ and -28. 2± 4. 7 mmHg by Tyr1-orphanin FQ at 10 min after administration,and this effect lasted over 30 min. The Phe1→Tyr substitution in orphanin FQ was found to retain almost fully hypotensive activity. Pretreatment of SHRsp with naloxone-HCI（60 μg/kg）, 5 min before the injection of orphanin FQ, did not block the hy- potensive effect of orphanin FQ. Therefore, opioid receptors could not account for the hypotensive effect of orphanin FQ in SHRsp. In Wistar rats, intravenous bolus injection of the same dose of orphanin FQ did not cause a change in MABP. These observations suggest that orphanin FQ is a novel hypotensive peptide and may have some role in the regulation of blood pressure in SHRsp, rather than in normotensive rats. The ex-act underlying mechanisms are waiting to be clarified.

Dietary <i>γ</i>-Aminobutyric Acid Shortens the Life Span of Stroke-Prone Spontaneously Hypertensive Rats

Dietary γ-amino butyric acid (GABA) has been suggested to decrease systolic blood pressure. This study aimed to ex-amine the effects of dietary GABA on the life span of stroke-prone spontaneously hypertensive rats (SHRSPs). In this study, life span was determined for SHRSPs provided 1% NaCl solution or 0.01% GABA in 1% NaCl solution as drinking water. The life span of the GABA-fed group (76.3 ± 1.65 days) was significantly shorter than that of the control group (81.6 ± 0.88 days). The results of this study may not be applicable to humans. Future studies will be necessary to elucidate the mechanism underlying this phenomenon.

Artificial cold exposure induced stroke in renovascular hypertensive rats and its association with cold-inducible RNA binding protein mRNA expression in brain tissue and blood pressure

BACKGROUND： High incidence of stroke at interchange period of autumn and winter was demonstrated by epidemiological survey, and the specific causes should be further investigated. OBJECTIVE： To investigate the influence of artificial cold exposure on the incidence of stroke in renovascular hypertensive rats （RHR）, and analyze the association with blood pressure and cold-inducible RNA binding protein （CIRP） mRNA expression in brain tissue. DESIGN： A completely randomized grouping design, a randomized control animal trial. SETTINGS： Lab of Neurology, the First Affiliated Hospital of Sun Yat-sen University; Department of Chemistry, Open laboratory of Chemical Biology, Institute of Molecular Technology for Drug Discovery and Synthesis, University of Hong Kong. MATERIALS： Male SD rats （n=460）, weighing 80 - 100 g were obtained from Guangdong Province Health Animal Unit. A modified RXZ-300A intelligent artificial climate cabinet （Ningbo Jiangnan Instrument Co. ,Ltd., China）. METHODS： The experiment were processed in the Lab of Neurology, the First Affiliated Hospital of Sun Yat-sen University and the Open Laboratory of Chemical Biology, Institute of Molecular Technology for Drug Discovery and Synthesis, University of Hong Kong from October 2004 to November 2005. Rats （n = 400） were operated to establish 2-kidney 2-clip RHR model as described previously. The sham-operated rats （n =60） served as normotensive controls. Eight weeks later, 300 of RHR were randomly selected according to their systolic blood pressure （SBP） and divided into 3 sub-groups （n =100 per group）： mild hypertensive group （SBP of 160 - 200 mm Hg）, moderate hypertensive group （SBP of 200 - 220 mm Hg） and severe hypertensive group （SBP 〉 220 mm Hg）. Each group was further divided into two groups （n =50） under ACE and non-ACE. Normal sham-operated SD rats （n =60）, SBP 〈 140 mm Hg, were randomly divided into two groups： Sham-operated control group （n =30） under ACE and non-ACE. To establish the ACE and non-ACE treatment, rats were housed individually in artificial climate cabinet, and ACE was designed as three cycles of 12-hour light of 22℃ （7 ： 00 - 19 ： 00） and 12-hour dark of 4℃（19 ： 00 - 7 ： 00）. The non-ACE group was kept at 22℃ throughout the experiment. MAIN OUTCOME MEASURES： Blood Pressure changes were measured and stroke symptom were observed; Expression of the CIRP were examined by reverse transcription-polymerase chain reaction. RESULTS： Finally 360 rats were involved in the analysis of results. ①Incidence of stroke： The incidence of stroke in 2k2c RHR was significantly higher after a three-day intermittent （12-hour） ACE （29.3%） as compared with that in non-ACE （17.3%） （P 〈 0.05）. Furthermore, the severe hypertensive 2k2c RHR （BP 〉 220 mm Hg） was found to have much higher incidence of stroke （66%, 33/50） than the mild （8%, 4/50） and moderate （18%） hypertensive 2k2c RHR. ②CIRP mRNA in brain tissue： ACE treatment stimulated the mRNA expression of CIRP in non-stroke 2k2c RHR but not in stroke 2k2c RHR （P 〈 0.05）. CONCLUSION： High blood pressure and low expression of CIRP are associated with ACE induced stroke.

Gene expression profiles in the peri-infarct brain cortex in a rat model of stroke-prone renovascular hypertension

BACKGROUND： Previous studies have focused on gene expression acutely following stroke onset. However, there have been a few reports of gene expression during later stages of cerebral infarction. OBJECTIVE： To determine gene expression profiling in the peri-infarct brain cortex 7 days after ischemia in a rat model of cerebral infarction in renovascular hypertensive rats. DESIGN, TIME AND SETTING： An in vivo, molecular experiment was performed at the Experimental Animal Center of Sun Yat-sen University and CapitalBio, Beijing, China between February 2004 and August 2005. MATERIALS： A 70-mer oligo chip containing 5 705 rat genes was supplied by CapitalBio, Beijing, China; and the Oligo rat gene bank was provided by Qiagen, the Netherlands. METHODS： Six Sprague Dawiey rats were utilized to establish a stroke-prone renovascular hypertensive model using the two-kidney and two-clip method. The rats were subsequently randomly assigned to two groups： middle cerebral artery occlusion and sham-operation, with three rats in each group. The middle cerebral artery occlusion model was induced by intraluminal suture method. Incisions were sutured following isolation of carotid arteries in the sham-operation group. MAIN OUTCOME MEASURES： Total RNA was extracted from the peri-infarct cerebral cortex 7 days after surgery. Following fluorescent labeling, RNA was hybridized to an Oligo chip containing 5 705 genes and was then scanned. Images were collected and the differentially expressed genes （number and category） were selected by data analysis. RESULTS： A total of 174 genes were upregulated, and 23 were downregulated, in the peri-infarct cerebral cortex 7 days after ischemia. The upregulated genes were distributed among 12 functional categories, and the downregulated genes belonged to categories of transport, transcription regulators, signals, response to stress, metabolism, and cell adhesion. The expression of some cytoskeletal genes was upregulated, including VIM, A2M, B2M, ACTR3, and ARPClB. Expression of a few cell adhesion-related genes （such as NLGN1, LGALS1, LGALS3, COLIA1, COL2A1, and SPP1） and other inflammation-related genes （such as CIQB, ClS, C4, C5R1, CFH, CD14, CD164, CD47, CD48, CD53, CD8B, IFNGR, and TFITM2） were upregulated. The glutamate-receptor gene GRIK5 was downregulated, which is related to the excitatory neurotransmitter glutamate. However, expression of the inhibitory neurotransmitter GABA-related genes was bidirectional - namely, GABRA5 downregulation and GABARAP upregulation. CONCLUSION： Upregulation of many cell adhesion and inflammation related genes and downregulation of excitatory glutamate-related receptor genes revealed active gene expression during later stages of cerebral infarction, which suggested molecular mechanisms of injury or repair.

Anti-hypertensive effects of rosiglitazone on renovascular hypertensive rats:role of oxidative stress and lipid metabolism

This study investigated the anti-hypertensive mechanismof rosiglitazone in renovascular hypertensive rats,and examined its relationship to oxidative stress and lipid metabolism. The renovascular hypertension was induced by stenosis of the left renal artery. Four groups of rats were selected： control,induced untreated,rosiglitazone（ 20 mg / kg） and captopril（ 10 mg / kg）. After 14 d of administration,compared with induced untreated group,rosiglitazone group reduced the renovascular hypertensive rats ＇ systolic blood pressure and diastolic blood pressure,and decreased total cholesterol（TCH）,triglyceride（TG）,angiotensin II（ Ang II） and angiotensin receptor（ AT1） levels（ P ＆lt; 0. 05）. Meanwhile,rosiglitazone remarkably decreased the levels of malondialdehyde（ MDA） and hydrogen peroxide（ H2O2） while improved the levels of supperoxide dismutase（ SOD） and reduced glutathione（ GSH）. These results suggested that rosiglitazone could effectively decreased the blood pressure in renovascular hypertensive rats,and this might be performed by regulating the activity of angiotensin and the lipid metabolismand improving the oxidative stress.

Effect of Hypertension on Hearing Function,LDH and ChE of the Cochlea in Older Rats

The relationship between the hypertension and the aging process of hearing organ was investigated Twenty Wistar 3-month old rats and 20 Wistar 12-month old rats, 20 spontaneously hypertensive rat stroke-prone (SHRSP) 3-month old rats and 20 SHRSP 12-month old rats free of middle ear infections as observed under otomicroscopy, with normal tympanic membrane and auricle reflex, were selected to be divided into two experimental groups and two control groups respectively The tail artery blood pressure was measured non-invasively The threshold of auditory brainstem response (ABR) was measured by Spirit TM evoked potential meter The LDH and ChE staining in the inner ear was performed and the optical density was analyzed by the HPIAS analysis system The results showed that there was no difference in the ABR thresholds, the activities of LDH and ChE between Wistar 3-month old group and SHRSP 3-month old group ( P >0 05) The mean value of ABR threshold and the activities of LDH and ChE in the Wistar 12-month old group at relevant sections were significantly greater than those in the two 3-month old groups ( P< 0 05), whereas the mean value of ABR threshold and the activities of LDH and ChE in the SHRSP 12-month old group at relevant sections were significantly higher than those in the 3-month old control group ( P< 0 01) It was concluded that presbycusis existed in the Wistar 12-month old group rats The glycogenosis and the abnormal secretion of neural transmitter were discerned after hypertension All the above factors may worsen the aging of the hearing system

Effect of Zhongfeng Naodeping Granule on Hippocampal Excitatory Amino Acid and Neuron of Stroke-Prone Spontaneously Hypertensive Rats with Hemorrhagic Apoplexy

Objective: To observe the effects ofZhongfeng Naodeping Granule (ZFNDPG) onhemorrhagic apoplexy. Methods: The strokeprone spontaneously hypertensive rats(SHRsp ) were used to study effects ofZFNDPG on hemorrhage apoplexy. Excitatoryamino acid (EAA) concentration in hippocampus sector, neuronal density and ultrastructural changes in hippocampal CAI sector weremeasured. Results: In pathological modelgroup glutamate (Gin) and aspartate (Asp)concentration elevated obviously. With theZFNDPG treating SHRsp of hemorrhagicapoplexy, Gin and Asp concentration in hippocampal sector could be markedly inhibited,compared with model group, P < 0.05-0. 01. Neuronal morphology was observed:neurone injury was mild and neuronal densityincreased in hippocampal CA1 sector of treatment group, compared with model group, P< 0. 01. Electron microscopy showed t edema,degeneration and necrosis caused by hemorrhagic apoplexy were improved after theZFNDPG treatment. Conclusions: Effects ofprotecting neurone for SHRsp on hemorrhagicapoplexy might be associated with thatZFNDPG inhibited concentration of EAA.

氯沙坦和培哚普利逆转高血压大鼠心血管重构的比较

目的 比较氯沙坦和培哚普利逆转肾血管性高血压大鼠心血管重构作用及其机制 ,为临床用药提供实验依据。方法 以经典两肾一夹肾血管性高血压大鼠为研究模型。采用鼠尾测压法测定大鼠血压的变化 ;反射免疫分析法测定大鼠血浆血管紧张素Ⅱ含量和肾素活性 ;称量法计算各组大鼠心脏与体重的比值 ;高清晰度数码照相扫描分析技术测定各组大鼠主动脉、肠系膜动脉血管管壁厚度、管壁厚度和管腔内径比值、管壁面积和管腔面积比值来估计两类药物对心血管重构的影响。结果 高血压大鼠心脏与体重的比值、主动脉、肠系膜动脉血管管壁厚度和管腔内径比值、管壁面积和管腔面积比值与正常大鼠相比明显增大 (P <0 0 1) ,给予氯沙坦 (2 0mg·kg-1)或培哚普利 (3mg·kg-1)治疗后 ,上述各项指标基本接近正常水平 ,与非用药组相比具有显著差异 (P<0 0 1)。结论 氯沙坦和培哚普利均能明显降低高血压大鼠血压 ;长期应用较低剂量氯沙坦和培哚普利均能有效逆转高血压大鼠病理性心血管重构 ,两药存在等效性。

丁苯酞对实验性动脉血栓形成性脑梗死的治疗作用

目的:观察丁苯酞(恩必普)对实验性动脉血栓形成性脑梗死的治疗作用.方法:按已定型的双肾双夹法建立易卒中型肾血管性高血压大鼠(RHRSP)模型,用光化学法造成大脑中动脉闭塞(MCAO)致大脑中动脉血栓形成.94只MCAO大鼠随机分为丁苯酞治疗组、生理氯化钠溶液(NS)对照组各47只,另取3只RHRSP作为假手术组.治疗组于MCA闭塞d1起po丁苯酞150 mg·kg-1,bid,给药10 d.每日行神经行为学评分, d10处死大鼠取脑进行TTC染色及常规病理检查,观察局部血栓梗死灶微血管等的变化.结果:丁苯酞治疗1～6d的神经行为学评分均明显增加(如d4治疗组(17.14±0.38)分, NS组(15.29±1.11)分,P<0.05);治疗组梗死面积为(6.94±2.11)mm2,梗死灶占前脑面积百分比在治疗组为(1.82±0.50)%,均显著低于NS组[(8.90±1.96)mm2和 (2.40±0.65)%,均为P<0.05];治疗组局部血栓变小、梗死灶及周围微血管增生也显著多于NS组(79% vs 62%,P<0.05),灶内出血发生率减少.结论:丁苯酞可改善病灶局部循环,减小梗死面积,减轻脑组织损伤,恢复神经功能.

降纤酶治疗脑梗死的实验研究

目的 观察降纤酶对光化学模型诱导的大鼠大脑中动脉血栓的溶栓作用及对脑梗死灶的影响。方法 应用光化学方法造成６０只易卒中型肾血管性高血压大鼠（ＲＨＲＳＰ）大脑中动脉（ＭＣＡ）血栓形成，在３ ｈ、６ ｈ、９ ｈ、１２ ｈ、１ ｄ不同的时间点对大鼠静脉注射 ３种产地的降纤酶 ８ Ｕ／ｋｇ，对照组注射等容生理盐水，观察 ２ ｄ，对大鼠进行行为学评分、ＭＣＡ血流测定、梗死灶体积测定、病理改变及出血情况观察。结果 降纤酶组３小时以内的血栓全部溶解，６小时内的部分溶解。降纤酶组各时间点无论血栓溶解与否，大鼠的行为学评分、梗死灶体积均较生理盐水组低，梗死灶周围微血管闭塞较生理盐水组少。但在降纤酶组中有２例发生出血，分别发生于血栓后６ ｈ、１２ ｈ用药组。结论 降纤酶对６小时以内的血栓有溶栓作用，对３小时以内的血栓溶解率最高。降纤酶除溶栓作用外，还可减少梗死灶体积，抑制微血管的血栓形成，改善微循环，改善卒中的预后。与其他溶栓剂相比并不增加出血并发症的发生。

珍菊降压片对肾性高血压大鼠血压的影响

目的 观察珍菊降压片 (ZJ)及其西药组分对肾性高血压大鼠 (RHR)血压和停药后血压反跳的影响 ,并研究其对RHR血脂与血脂蛋白的影响。方法 左肾动脉狭窄法建立两肾一夹高血压大鼠模型 ;无创尾套法测量清醒RHR尾动脉收缩压。结果 与模型组比较 ,ZJ组 (4 0mg·kg-1,80mg·kg-1,16 0mg·kg-1)及西药组分组 (1.79mg·kg-1,相当于全药中剂量组 )对RHR有明显的降压作用 (P <0 .0 1) ;ZJ各剂量间降压作用无显著性差异 ;同比剂量组(80mg·kg-1)与西药组分组 (1.79mg·kg-1)降压作用无显著性差异 (P >0 .0 5 ) ;与西药组分组 (1.79mg·kg-1)比较 ,ZJ未出现血压反跳现象 (P <0 .0 5 ) ;ZJ对血脂和血脂蛋白无显著性影响 (P >0 .0 5 )。结论 珍菊降压片有良好的抗高血压作用 。

星形细胞活性及GFAP在评价脑梗死中的作用及意义

目的 :观察星形胶质细胞的超微结构及胶质纤维酸性蛋白 (GFAP)脑梗死后的变化 ,并探讨GFAP在急性脑梗塞后的作用。方法 :用双肾双夹易卒中型肾血管性高血压鼠 (RHRSP)复制右大脑中动脉闭塞 (MCAO)模型 ,分MCAO后 1、3、6、9周末 4个时间组 ,每组均进行脑梗死灶边缘区 (A区 ) ,近顶叶皮层的远隔区 (B区 ) ,对侧皮层与A区相对应的镜区 (C区 )的电镜观察 ,并测定各区的GFAP阳性细胞数目及光密度值。结果 :脑梗死后星形细胞在全脑的增殖均较活跃。在脑梗死后GFAP阳性细胞数在边缘区最高 ,B区次之 ,C区最少。在缺血时间上 ,其改变以MCAO后 1周末最高 ,3- 6周末次之 ,9周末最少。GFAP阳性细胞浆平均光密度值变化情况与GFAP阳性细胞数目变化基本相同。结论 :星形胶质细胞增殖程度和脑梗死后脑组织病变程度可用GFAP的表达值进行评价 。

肾血管性高血压大鼠自发脑卒中

通过研究双肾双夹型肾血管性高血压大鼠自发脑卒中的病理形态,发现高血压所致的脑内细小动脉纤维素样坏死、透明变性和微动脉瘤形成等是出血性脑卒中和脑梗塞的共同病理基础。探讨了高血压动脉硬化性脑卒中的发病机制,并为混合性脑卒中提供了实验依据。

四逆汤(附子、干姜、甘草)对肾血管性高血压大鼠血压调节作用的实验研究

目的探讨四逆汤对肾血管性高血压大鼠血压的调节作用和可能的机制。方法健康雌性Wistar大鼠24只,随机分为正常组、对照组和治疗组,每组8只。根据双肾动脉夹闭法建立肾性高血压动物模型,应用四逆汤(附子、干姜、甘草)灌胃治疗2周,RBF-2型鼠尾动脉血压计测量血压,放射免疫法测定血浆中血管紧张素Ⅱ(AngⅡ)和降钙素基因相关肽(CGRP)的含量,TUNEL法检测肾组织细胞凋亡,免疫组化法测定肾组织中AngⅡ和CGRP的表达。结果(1)对照组和治疗组大鼠血压较正常组明显升高,四逆汤能明显降低血压[(131.6±14.2vs116.2±8.3)mmHg,P<0.05]。(2)各组动物血浆AngⅡ水平无显著性变化(P>0.05),治疗组CGRP含量较对照组明显升高[(75.2±12.2vs54.8±18.1)pg/mL,P<0.05]。(3)四逆汤治疗明显减少肾小球凋亡阳性细胞数(12.6±3.5vs29.4±3.5细胞个数/10个视野,P<0.05);治疗组明显降低AngⅡ表达水平,显著升高CGRP表达水平(P<0.05)。结论四逆汤可能通过调节肾血管性高血压大鼠血浆和肾组织中血管活性物质AngⅡ和CGRP的水平,发挥其血压调节和保护高血压靶器官的作用。

中国毛虾酶解多肽降压作用的初步探讨

初步探讨从中国毛虾(Aceteschinensis)经碱性及中性蛋白酶降解获得的多肽(AP、NP)的降压作用及相关机制。采用Cushman-Cheung方法测定酶解多肽体外对血管紧张素酶(ACE)活性的影响;采用两肾一夹型建立肾血管性高血压大鼠模型,分别长期预防给药及急性治疗给药;应用GY-6088型多道生理参数分析记录仪和张力传感器测定、记录血压和呼吸;采用均相竞争法测定大鼠血浆中血管紧张素Ⅱ(AngⅡ)的含量。结果表明,2种酶解多肽体外均能明显抑制ACE的活性,AP和NP的半数抑制浓度(IC50)分别为15.61mg/L和16.95mg/L;无论是长期预防给药还是急性治疗给药,二者均能显著地降低肾血管性高血压大鼠的动脉血压;经口服预防给药能明显降低高血压大鼠血浆中的AngⅡ水平;给药大鼠的呼吸频率随血压的变化呈正相关变化;碱性酶解多肽的降压作用及抑制ACE生成的作用均强于中性酶解多肽,其中,200μg/g的AP降压效果最好,与14μg/g的卡托普利相当。中国毛虾酶解多肽无论是长期预防给药还是急性治疗给药对肾性高血压大鼠均有显著的降压作用,抑制AngⅡ的生成可能是其降压机制之一。

实验性大脑皮层梗死后中枢神经系统相关部位的神经可塑性

目的 :探讨实验性大脑皮层梗塞后同侧纹状体、丘脑及对侧脊髓前角的神经结构可塑性。方法 :采用易卒中型肾血管性高血压大鼠制作右侧大脑中动脉皮层支闭塞模型 ,分别于术后第 1周、2周、3周和 4周 ,取鼠脑行免疫组化检查 ,检测大鼠不同时点纹状体、丘脑腹后外侧核及对侧脊髓前角的微管相关蛋白 2 (MAP 2 )、突触生长素(SYN)和生长相关蛋白 (GAP 43)表达的变化。结果 :大脑皮层梗塞后第 1周 ,同侧纹状体、丘脑腹后外侧核和对侧脊髓前角GAP 43阳性信号开始增加 ,第 2周达到高峰 ,之后增加幅度逐渐减弱 ;这些部位SYN阳性信号第 1周较对照组高 ,至第 2周恢复正常 ,第 3周和第 4周逐渐降低 ,且显著低于对照组 ;脑皮层梗塞后第 2周 ,同侧纹状体和丘脑腹后外侧核MAP 2阳性细胞数开始减少 ,至 3周、4周显著低于对照组。结论 :大脑皮层梗死后早期远离梗塞灶的相关神经组织有明显的可塑性 。

人工寒潮时不同血压水平大鼠脑卒中发病的实验研究

目的探讨人工寒潮时不同血压水平对脑卒中发病的影响。方法360只大鼠分为寒潮和非寒潮2大组,再按血压水平各分为正常血压组、160～199mmHg、200～219mmHg和≥220mmHg等4个亚组,观察大鼠的脑卒中情况。结果脑卒中发生率在血压<220mmHg与≥220mmHg的大鼠、寒潮组与非寒潮组之间均有显著性差异。脑动脉病变严重的卒中率更高。Logistic回归发现只有寒潮前高血压是脑卒中发生的唯一独立危险因素。结论高血压、寒潮与脑卒中发病密切相关,脑动脉病变是患病基础,高血压是脑卒中的独立危险因素,而寒潮是重要的启动因子。