Vascular oxidative stress,nitric oxide and atherosclerosis

In the vascular wall, reactive oxygen species (ROS) are produced by several enzyme systems including NADPH oxidase, xanthine oxidase, uncoupled endothelial nitric oxide synthase (eNOS) and the mitochondrial electron transport chain. On the other hand, the vasculature is protected by antioxidant enzyme systems, including superoxide dismutases, catalase, glutathione peroxidases and paraoxonases, which detoxify ROS. Cardiovascular risk factors such as hypercholesterolemia, hypertension, and diabetes mellitus enhance ROS generation, resulting in oxidative stress. This leads to oxidative modification of lipoproteins and phospholipids, mechanisms that contribute to atherogenesis. In addition, oxidation of tetrahydrobiopterin may cause eNOS uncoupling and thus potentiation of oxidative stress and reduction of eNOS-derived NO, which is a protective principle in the vasculature. This review summarizes the latest advances in the role of ROS-producing enzymes, antioxidative enzymes as well as NO synthases in the initiation and development of atherosclerosis.     

家兔动脉粥样硬化与血小板源内皮型氧化氮合酶表达的相关性

目的 探讨家兔动脉粥样硬化及斑块形成与血小板源内皮型氧化氮合酶(eNOS)表达的关系. 方法 设立模型组、治疗组和非治疗组及对照组,每组家兔6只.模型组、治疗组和非治疗组每天给予胆固醇饮食,至12周建立家兔动脉粥样硬化模型,建模后继续喂养至24周,同时治疗组服用普伐他汀10 mg/d;非治疗组仅给予普通饮食.实验终点剥离家兔主动脉观察大体和组织病理形态,反转录一聚合酶链式反应(RT-PCR)方法 检测血小板源eNOS/mRNA水平. 结果 模型组和非治疗组均可见明显动脉粥样硬化和(或)斑块形成;主动脉最大脂纹或斑块厚度占整个血管壁厚度的百分比,对照组、模型组、治疗组和非治疗组分别是0.04±0.02、0.82±0.16、0.33±0.18和0.77±0.14,治疗组与非治疗组比较,差异有统计学意义(F=33.759,P=0.001).血小板(2～4×108/ml)eNOS mRNA表达在对照组、模型组、治疗组和非治疗组分别是1.02±0.28、0.41±0.27、1.00±0.77、0.40±0.29,治疗组较非治疗组明显增高(F=3.544,P=0.02). 结论 血小板源eNOS表达与动脉粥样硬化及斑块的形成呈负相关;普伐他汀对动脉粥样硬化及斑块的逆转作用可能与血小板源eNOS有关.     

Therapeutic potential of nitric oxide donors in the prevention and treatment of angiogenesis-inhibitor-induced hypertension

Angiogenesis is critical to tumor growth as well as to metastases. This process is tightly regulated by pro- and anti-angiogenic growth factors and their receptors. Some of these factors are highly specific for the endothelium—e.g., vascular endothelial growth factor (VEGF). A variety of drugs that target VEGF or its receptors have been developed for the treatment of different tumor types and a number of new agents is expected to be introduced within the coming years. However, clinical experience has revealed that inhibition of VEGF induces several side effects including hypertension and renal and cardiac toxicity. Angiogenesis-inhibitor-induced hypertension represents “crux medicorum” as it is often pharmacoresistant to antihypertensive therapy. We consider two most important pathomechanisms in the development of hypertension induced by angiogenesis inhibitors. The first represents direct inhibition of NO production leading to reduced vasodilatation and the second consists in increased proliferation of vascular medial cells mediated by NO deficiency and is resulting in fixation of hypertension. Based on the results of experimental and clinical studies as well as on our clinical experience, we assume that NO donors could be successfully used not only for the treatment of developed angiogenesis-inhibitor-induced hypertension but also for preventive effects. We thoroughly documented three clinical cases of cancer patients with resistant hypertension who on receiving NO donor treatment achieved target blood pressure level and a good clinical status.     

内皮素、一氧化氮与老年动脉硬化闭塞症相互关系的探讨

目的：从分子生物学角度探讨内皮素（ＥＴ）、一氧化氮（ＮＯ）与动脉硬化闭塞症（ＡＳＯ）的相互关系,方法选择９６例ＡＳＯ患者和８６只模型,利用放射免疫,Ｇｒｉｓｓ、光电比色和逆转录ＰＣＲ方法检测血浆ＥＴ、ＮＯ和血管一氧化氮合酶（ＮＯＳ）活性、ＥＴｍＲＮＡ和ＮＯＳｍＲＮＡ表达情况。结果ＡＳＯ患者和模型存在高ＥＴ血症和低症,ＡＳＯ病变血管存在低ＮＯＳ活性、低ＮＯＳｍＲＮＡ表达和高ＥＴｍＲＮＡ表达状态,并同     

Myocardial release of nitric oxide during ischaemia and reperfusion: effects of L-arginine and hypercholesterolaemia

AIMS: Nitric oxide (NO) may modulate myocardial ischaemia/reperfusion (I/R) injury, but effects of hypercholesterolaemia on myocardial NO release during I/R are unknown. METHODS: A NO-specific carbon fibre electrode continuously measured coronary sinus [NO] during 60 min low-flow ischaemia (1 ml/min) and 60 min free reperfusion (I/R) in isolated rabbit hearts. Experimental groups (n=7 per group) were control, L-arginine supplement (200 microM), N-nitro-L-arginine methyl ester (L-NAME) treatment (8 microM) and hypercholesterolaemic. RESULTS: During early I, NO release decreased markedly in control (-1356+/-286 pmol/min/g) and L-arginine (-1972+/-172) groups, but less in L-NAME (-441+/-89) and hypercholesterolaemic (-602+/-164) groups (both p<0.01 vs. controls). No increase in NO release during I was seen in any group. After R, NO release increased above baseline in control (+2333+/-591 pmol/min/g) and L-arginine (+1048+/-278) groups and hypercholesterolaemic (+1100+/-478) (p<0.05 vs. pre-ischaemia each group). There was little increase in NO release in the L-NAME group (+436+/-247 pmol/min/g, p<0.05 vs. controls). In each group, myocardial NO release declined towards pre-ischaemic levels during 60 min R. Hearts treated with L-arginine had similar NO release but better functional recovery than controls (p<0.01). Treatment with L-NAME was also associated with better functional recovery than in controls or hypercholesterolaemic hearts. CONCLUSION: Myocardial NO release declines rapidly during ischaemia, but increases above baseline during early reperfusion. Improved function after L-arginine treatment appears to be independent of effects upon NO release. Hypercholesterolaemia is associated with reduced myocardial NO release, under both baseline conditions and during ischaemia and reperfusion.     

一氧化氮及其合酶在哮喘发病机制中的作用

探讨一氧化氮及其合酶在哮喘发病机制中的作用。方法 采用哮喘豚鼠模型，将豚鼠分为４组；１．哮喘组，用１０％卵白蛋白腹腔注射１ｍｌ致敏，２周后用１％卵白蛋白超声雾化吸入致其哮喘发作．２；肾上腺皮质激素预防组；诱喘同哮喘组，在每次诱喘前腹腔滴注地塞米松０．５ｍｇ／ｋｇ。３．硝基精氨酸甲酯预防组；诱喘同哮喘组，每次诱喘产腹腔注射ＬＮＮＡ０．４ｍｇ／ｋｇ。４．正常对照组；用生理盐水代替诱喘剂。每组分别测定其     

老年大鼠大脑组织一氧化氮、一氧化氮合酶的变化及神经细胞凋亡研究

目的研究一氧化氮(NO)、一氧化氮合酶(NOS)在老年大鼠大脑中的变化及其与神经细胞凋亡的关系. 方法选用5月龄大鼠和30月龄大鼠,利用Griess反应和高压液相技术间接测量大脑NO水平和NOS活性;免疫组化和原位杂交技术分别检测神经元NOS(nNOS)蛋白质水平和nNOS、bcl-2基因水平;末端转移酶标记法原位检测大脑神经细胞凋亡状况. 结果老年大鼠大脑组织NO水平和nNOS活性分别是(2.61±0.10)μmol*L-1和(398.22±21.62)fmol*mg-1*min-1,显著高于青年大鼠的(1.54±0.15)μmol*L-1和(234.38±16.24)fmol*mg-1*min-1.老年大鼠大脑nNOS的基因水平和蛋白表达水平均升高,抗凋亡基因bcl-2水平降低.在老年大鼠大脑质皮检测到散在的凋亡细胞. 结论老年大鼠大脑组织NO水平升高是由于nNOS活性升高所致.nNOS活性的增高部分是由其基因和蛋白水平来决定的.老年大鼠大脑组织NO异常升高可能是导致神经组织损伤进而凋亡的原因之一.     

家兔动脉粥样硬化与血小板源内皮型氧化氮合酶表达的相关性

Objective To explore the correlation of atheroselerosis progression and the expression of platelet derived endothelial nitric oxide synthase (eNOS) in rabbits. Methods A total of 24 male New Zealand white rabbits were used in this study. Six of the animals were fed with normal food (control group). Eighteen rabbits were fed with cholesterol-rich food (1 g/d) for 12 weeks to establish the atherosclerosis model. Among 18 models, 6 rabbits were executed immediately and their aorta and platelet samples were collected for further analysis (model group), 6 rabbits were orally administered with pravastatin (10 rag/d) for additional 12 weeks (treated group), and the remaining 6 rabbits were left untreated until the end of the study (untreated group). The control, treated and untreated animals were then killed, and the aorta and platelet samples were collected for eNOS expression analysis (RT-PCR). Results The aorta samples in model and untreated group exhibited rough intima and a lot of longitudinal fatty streaks, which indicated that atherosclerosis models were established successfully. While in treated group, the degree of atherosclerosis was decreased. The average percent of thickness of fatty streaks or atheroselerotic plaques relative to the whole thickness of vessel walls was 0. 04±0. 02, 0. 82±0. 16, 0. 33±0. 18,0. 77±0. 14 in control, model, treated and untreated group, respectively. The thickness of fatty streaks or atherosclerotic plaques was significantly increased in the model and untreated groups and decreased in treated group compared with the control group (both P<0. 05). The expressions of platelet derived eNOS/mRNA were 1. 02± 0. 28, 0. 41± 0. 27, 1.00 ± 0. 77, 0. 40±0. 29 in control, model, treated and untreated group, respectively. The expression of eNOS/mRNA was markedly decreased in model group and untreated group compared with the control group, but was increased in treated group compared with untreated and model groups (F=3. 544, P = 0. 024). Conclusions There is a negative correlation between eNOS expression and atherosclerosis development, which suggests that the reversal effect of pravastatin on atheroselerosis progression and plaque formation may relate to the expression of platelet derived eNOS.     

家兔动脉粥样硬化与血小板源内皮型氧化氮合酶表达的相关性

Objective To explore the correlation of atheroselerosis progression and the expression of platelet derived endothelial nitric oxide synthase (eNOS) in rabbits. Methods A total of 24 male New Zealand white rabbits were used in this study. Six of the animals were fed with normal food (control group). Eighteen rabbits were fed with cholesterol-rich food (1 g/d) for 12 weeks to establish the atherosclerosis model. Among 18 models, 6 rabbits were executed immediately and their aorta and platelet samples were collected for further analysis (model group), 6 rabbits were orally administered with pravastatin (10 rag/d) for additional 12 weeks (treated group), and the remaining 6 rabbits were left untreated until the end of the study (untreated group). The control, treated and untreated animals were then killed, and the aorta and platelet samples were collected for eNOS expression analysis (RT-PCR). Results The aorta samples in model and untreated group exhibited rough intima and a lot of longitudinal fatty streaks, which indicated that atherosclerosis models were established successfully. While in treated group, the degree of atherosclerosis was decreased. The average percent of thickness of fatty streaks or atheroselerotic plaques relative to the whole thickness of vessel walls was 0. 04±0. 02, 0. 82±0. 16, 0. 33±0. 18,0. 77±0. 14 in control, model, treated and untreated group, respectively. The thickness of fatty streaks or atherosclerotic plaques was significantly increased in the model and untreated groups and decreased in treated group compared with the control group (both P<0. 05). The expressions of platelet derived eNOS/mRNA were 1. 02± 0. 28, 0. 41± 0. 27, 1.00 ± 0. 77, 0. 40±0. 29 in control, model, treated and untreated group, respectively. The expression of eNOS/mRNA was markedly decreased in model group and untreated group compared with the control group, but was increased in treated group compared with untreated and model groups (F=3. 544, P = 0. 024). Conclusions There is a negative correlation between eNOS expression and atherosclerosis development, which suggests that the reversal effect of pravastatin on atheroselerosis progression and plaque formation may relate to the expression of platelet derived eNOS.     

家兔动脉粥样硬化与血小板源内皮型氧化氮合酶表达的相关性

Objective To explore the correlation of atheroselerosis progression and the expression of platelet derived endothelial nitric oxide synthase (eNOS) in rabbits. Methods A total of 24 male New Zealand white rabbits were used in this study. Six of the animals were fed with normal food (control group). Eighteen rabbits were fed with cholesterol-rich food (1 g/d) for 12 weeks to establish the atherosclerosis model. Among 18 models, 6 rabbits were executed immediately and their aorta and platelet samples were collected for further analysis (model group), 6 rabbits were orally administered with pravastatin (10 rag/d) for additional 12 weeks (treated group), and the remaining 6 rabbits were left untreated until the end of the study (untreated group). The control, treated and untreated animals were then killed, and the aorta and platelet samples were collected for eNOS expression analysis (RT-PCR). Results The aorta samples in model and untreated group exhibited rough intima and a lot of longitudinal fatty streaks, which indicated that atherosclerosis models were established successfully. While in treated group, the degree of atherosclerosis was decreased. The average percent of thickness of fatty streaks or atheroselerotic plaques relative to the whole thickness of vessel walls was 0. 04±0. 02, 0. 82±0. 16, 0. 33±0. 18,0. 77±0. 14 in control, model, treated and untreated group, respectively. The thickness of fatty streaks or atherosclerotic plaques was significantly increased in the model and untreated groups and decreased in treated group compared with the control group (both P<0. 05). The expressions of platelet derived eNOS/mRNA were 1. 02± 0. 28, 0. 41± 0. 27, 1.00 ± 0. 77, 0. 40±0. 29 in control, model, treated and untreated group, respectively. The expression of eNOS/mRNA was markedly decreased in model group and untreated group compared with the control group, but was increased in treated group compared with untreated and model groups (F=3. 544, P = 0. 024). Conclusions There is a negative correlation between eNOS expression and atherosclerosis development, which suggests that the reversal effect of pravastatin on atheroselerosis progression and plaque formation may relate to the expression of platelet derived eNOS.     

家兔动脉粥样硬化与血小板源内皮型氧化氮合酶表达的相关性

Objective To explore the correlation of atheroselerosis progression and the expression of platelet derived endothelial nitric oxide synthase (eNOS) in rabbits. Methods A total of 24 male New Zealand white rabbits were used in this study. Six of the animals were fed with normal food (control group). Eighteen rabbits were fed with cholesterol-rich food (1 g/d) for 12 weeks to establish the atherosclerosis model. Among 18 models, 6 rabbits were executed immediately and their aorta and platelet samples were collected for further analysis (model group), 6 rabbits were orally administered with pravastatin (10 rag/d) for additional 12 weeks (treated group), and the remaining 6 rabbits were left untreated until the end of the study (untreated group). The control, treated and untreated animals were then killed, and the aorta and platelet samples were collected for eNOS expression analysis (RT-PCR). Results The aorta samples in model and untreated group exhibited rough intima and a lot of longitudinal fatty streaks, which indicated that atherosclerosis models were established successfully. While in treated group, the degree of atherosclerosis was decreased. The average percent of thickness of fatty streaks or atheroselerotic plaques relative to the whole thickness of vessel walls was 0. 04±0. 02, 0. 82±0. 16, 0. 33±0. 18,0. 77±0. 14 in control, model, treated and untreated group, respectively. The thickness of fatty streaks or atherosclerotic plaques was significantly increased in the model and untreated groups and decreased in treated group compared with the control group (both P<0. 05). The expressions of platelet derived eNOS/mRNA were 1. 02± 0. 28, 0. 41± 0. 27, 1.00 ± 0. 77, 0. 40±0. 29 in control, model, treated and untreated group, respectively. The expression of eNOS/mRNA was markedly decreased in model group and untreated group compared with the control group, but was increased in treated group compared with untreated and model groups (F=3. 544, P = 0. 024). Conclusions There is a negative correlation between eNOS expression and atherosclerosis development, which suggests that the reversal effect of pravastatin on atheroselerosis progression and plaque formation may relate to the expression of platelet derived eNOS.     

家兔动脉粥样硬化与血小板源内皮型氧化氮合酶表达的相关性

Objective To explore the correlation of atheroselerosis progression and the expression of platelet derived endothelial nitric oxide synthase (eNOS) in rabbits. Methods A total of 24 male New Zealand white rabbits were used in this study. Six of the animals were fed with normal food (control group). Eighteen rabbits were fed with cholesterol-rich food (1 g/d) for 12 weeks to establish the atherosclerosis model. Among 18 models, 6 rabbits were executed immediately and their aorta and platelet samples were collected for further analysis (model group), 6 rabbits were orally administered with pravastatin (10 rag/d) for additional 12 weeks (treated group), and the remaining 6 rabbits were left untreated until the end of the study (untreated group). The control, treated and untreated animals were then killed, and the aorta and platelet samples were collected for eNOS expression analysis (RT-PCR). Results The aorta samples in model and untreated group exhibited rough intima and a lot of longitudinal fatty streaks, which indicated that atherosclerosis models were established successfully. While in treated group, the degree of atherosclerosis was decreased. The average percent of thickness of fatty streaks or atheroselerotic plaques relative to the whole thickness of vessel walls was 0. 04±0. 02, 0. 82±0. 16, 0. 33±0. 18,0. 77±0. 14 in control, model, treated and untreated group, respectively. The thickness of fatty streaks or atherosclerotic plaques was significantly increased in the model and untreated groups and decreased in treated group compared with the control group (both P<0. 05). The expressions of platelet derived eNOS/mRNA were 1. 02± 0. 28, 0. 41± 0. 27, 1.00 ± 0. 77, 0. 40±0. 29 in control, model, treated and untreated group, respectively. The expression of eNOS/mRNA was markedly decreased in model group and untreated group compared with the control group, but was increased in treated group compared with untreated and model groups (F=3. 544, P = 0. 024). Conclusions There is a negative correlation between eNOS expression and atherosclerosis development, which suggests that the reversal effect of pravastatin on atheroselerosis progression and plaque formation may relate to the expression of platelet derived eNOS.     

家兔动脉粥样硬化与血小板源内皮型氧化氮合酶表达的相关性

Objective To explore the correlation of atheroselerosis progression and the expression of platelet derived endothelial nitric oxide synthase (eNOS) in rabbits. Methods A total of 24 male New Zealand white rabbits were used in this study. Six of the animals were fed with normal food (control group). Eighteen rabbits were fed with cholesterol-rich food (1 g/d) for 12 weeks to establish the atherosclerosis model. Among 18 models, 6 rabbits were executed immediately and their aorta and platelet samples were collected for further analysis (model group), 6 rabbits were orally administered with pravastatin (10 rag/d) for additional 12 weeks (treated group), and the remaining 6 rabbits were left untreated until the end of the study (untreated group). The control, treated and untreated animals were then killed, and the aorta and platelet samples were collected for eNOS expression analysis (RT-PCR). Results The aorta samples in model and untreated group exhibited rough intima and a lot of longitudinal fatty streaks, which indicated that atherosclerosis models were established successfully. While in treated group, the degree of atherosclerosis was decreased. The average percent of thickness of fatty streaks or atheroselerotic plaques relative to the whole thickness of vessel walls was 0. 04±0. 02, 0. 82±0. 16, 0. 33±0. 18,0. 77±0. 14 in control, model, treated and untreated group, respectively. The thickness of fatty streaks or atherosclerotic plaques was significantly increased in the model and untreated groups and decreased in treated group compared with the control group (both P<0. 05). The expressions of platelet derived eNOS/mRNA were 1. 02± 0. 28, 0. 41± 0. 27, 1.00 ± 0. 77, 0. 40±0. 29 in control, model, treated and untreated group, respectively. The expression of eNOS/mRNA was markedly decreased in model group and untreated group compared with the control group, but was increased in treated group compared with untreated and model groups (F=3. 544, P = 0. 024). Conclusions There is a negative correlation between eNOS expression and atherosclerosis development, which suggests that the reversal effect of pravastatin on atheroselerosis progression and plaque formation may relate to the expression of platelet derived eNOS.     

家兔动脉粥样硬化与血小板源内皮型氧化氮合酶表达的相关性

Objective To explore the correlation of atheroselerosis progression and the expression of platelet derived endothelial nitric oxide synthase (eNOS) in rabbits. Methods A total of 24 male New Zealand white rabbits were used in this study. Six of the animals were fed with normal food (control group). Eighteen rabbits were fed with cholesterol-rich food (1 g/d) for 12 weeks to establish the atherosclerosis model. Among 18 models, 6 rabbits were executed immediately and their aorta and platelet samples were collected for further analysis (model group), 6 rabbits were orally administered with pravastatin (10 rag/d) for additional 12 weeks (treated group), and the remaining 6 rabbits were left untreated until the end of the study (untreated group). The control, treated and untreated animals were then killed, and the aorta and platelet samples were collected for eNOS expression analysis (RT-PCR). Results The aorta samples in model and untreated group exhibited rough intima and a lot of longitudinal fatty streaks, which indicated that atherosclerosis models were established successfully. While in treated group, the degree of atherosclerosis was decreased. The average percent of thickness of fatty streaks or atheroselerotic plaques relative to the whole thickness of vessel walls was 0. 04±0. 02, 0. 82±0. 16, 0. 33±0. 18,0. 77±0. 14 in control, model, treated and untreated group, respectively. The thickness of fatty streaks or atherosclerotic plaques was significantly increased in the model and untreated groups and decreased in treated group compared with the control group (both P<0. 05). The expressions of platelet derived eNOS/mRNA were 1. 02± 0. 28, 0. 41± 0. 27, 1.00 ± 0. 77, 0. 40±0. 29 in control, model, treated and untreated group, respectively. The expression of eNOS/mRNA was markedly decreased in model group and untreated group compared with the control group, but was increased in treated group compared with untreated and model groups (F=3. 544, P = 0. 024). Conclusions There is a negative correlation between eNOS expression and atherosclerosis development, which suggests that the reversal effect of pravastatin on atheroselerosis progression and plaque formation may relate to the expression of platelet derived eNOS.     

家兔动脉粥样硬化与血小板源内皮型氧化氮合酶表达的相关性

Objective To explore the correlation of atheroselerosis progression and the expression of platelet derived endothelial nitric oxide synthase (eNOS) in rabbits. Methods A total of 24 male New Zealand white rabbits were used in this study. Six of the animals were fed with normal food (control group). Eighteen rabbits were fed with cholesterol-rich food (1 g/d) for 12 weeks to establish the atherosclerosis model. Among 18 models, 6 rabbits were executed immediately and their aorta and platelet samples were collected for further analysis (model group), 6 rabbits were orally administered with pravastatin (10 rag/d) for additional 12 weeks (treated group), and the remaining 6 rabbits were left untreated until the end of the study (untreated group). The control, treated and untreated animals were then killed, and the aorta and platelet samples were collected for eNOS expression analysis (RT-PCR). Results The aorta samples in model and untreated group exhibited rough intima and a lot of longitudinal fatty streaks, which indicated that atherosclerosis models were established successfully. While in treated group, the degree of atherosclerosis was decreased. The average percent of thickness of fatty streaks or atheroselerotic plaques relative to the whole thickness of vessel walls was 0. 04±0. 02, 0. 82±0. 16, 0. 33±0. 18,0. 77±0. 14 in control, model, treated and untreated group, respectively. The thickness of fatty streaks or atherosclerotic plaques was significantly increased in the model and untreated groups and decreased in treated group compared with the control group (both P<0. 05). The expressions of platelet derived eNOS/mRNA were 1. 02± 0. 28, 0. 41± 0. 27, 1.00 ± 0. 77, 0. 40±0. 29 in control, model, treated and untreated group, respectively. The expression of eNOS/mRNA was markedly decreased in model group and untreated group compared with the control group, but was increased in treated group compared with untreated and model groups (F=3. 544, P = 0. 024). Conclusions There is a negative correlation between eNOS expression and atherosclerosis development, which suggests that the reversal effect of pravastatin on atheroselerosis progression and plaque formation may relate to the expression of platelet derived eNOS.     

家兔动脉粥样硬化与血小板源内皮型氧化氮合酶表达的相关性

Objective To explore the correlation of atheroselerosis progression and the expression of platelet derived endothelial nitric oxide synthase (eNOS) in rabbits. Methods A total of 24 male New Zealand white rabbits were used in this study. Six of the animals were fed with normal food (control group). Eighteen rabbits were fed with cholesterol-rich food (1 g/d) for 12 weeks to establish the atherosclerosis model. Among 18 models, 6 rabbits were executed immediately and their aorta and platelet samples were collected for further analysis (model group), 6 rabbits were orally administered with pravastatin (10 rag/d) for additional 12 weeks (treated group), and the remaining 6 rabbits were left untreated until the end of the study (untreated group). The control, treated and untreated animals were then killed, and the aorta and platelet samples were collected for eNOS expression analysis (RT-PCR). Results The aorta samples in model and untreated group exhibited rough intima and a lot of longitudinal fatty streaks, which indicated that atherosclerosis models were established successfully. While in treated group, the degree of atherosclerosis was decreased. The average percent of thickness of fatty streaks or atheroselerotic plaques relative to the whole thickness of vessel walls was 0. 04±0. 02, 0. 82±0. 16, 0. 33±0. 18,0. 77±0. 14 in control, model, treated and untreated group, respectively. The thickness of fatty streaks or atherosclerotic plaques was significantly increased in the model and untreated groups and decreased in treated group compared with the control group (both P<0. 05). The expressions of platelet derived eNOS/mRNA were 1. 02± 0. 28, 0. 41± 0. 27, 1.00 ± 0. 77, 0. 40±0. 29 in control, model, treated and untreated group, respectively. The expression of eNOS/mRNA was markedly decreased in model group and untreated group compared with the control group, but was increased in treated group compared with untreated and model groups (F=3. 544, P = 0. 024). Conclusions There is a negative correlation between eNOS expression and atherosclerosis development, which suggests that the reversal effect of pravastatin on atheroselerosis progression and plaque formation may relate to the expression of platelet derived eNOS.     

家兔动脉粥样硬化与血小板源内皮型氧化氮合酶表达的相关性

Objective To explore the correlation of atheroselerosis progression and the expression of platelet derived endothelial nitric oxide synthase (eNOS) in rabbits. Methods A total of 24 male New Zealand white rabbits were used in this study. Six of the animals were fed with normal food (control group). Eighteen rabbits were fed with cholesterol-rich food (1 g/d) for 12 weeks to establish the atherosclerosis model. Among 18 models, 6 rabbits were executed immediately and their aorta and platelet samples were collected for further analysis (model group), 6 rabbits were orally administered with pravastatin (10 rag/d) for additional 12 weeks (treated group), and the remaining 6 rabbits were left untreated until the end of the study (untreated group). The control, treated and untreated animals were then killed, and the aorta and platelet samples were collected for eNOS expression analysis (RT-PCR). Results The aorta samples in model and untreated group exhibited rough intima and a lot of longitudinal fatty streaks, which indicated that atherosclerosis models were established successfully. While in treated group, the degree of atherosclerosis was decreased. The average percent of thickness of fatty streaks or atheroselerotic plaques relative to the whole thickness of vessel walls was 0. 04±0. 02, 0. 82±0. 16, 0. 33±0. 18,0. 77±0. 14 in control, model, treated and untreated group, respectively. The thickness of fatty streaks or atherosclerotic plaques was significantly increased in the model and untreated groups and decreased in treated group compared with the control group (both P<0. 05). The expressions of platelet derived eNOS/mRNA were 1. 02± 0. 28, 0. 41± 0. 27, 1.00 ± 0. 77, 0. 40±0. 29 in control, model, treated and untreated group, respectively. The expression of eNOS/mRNA was markedly decreased in model group and untreated group compared with the control group, but was increased in treated group compared with untreated and model groups (F=3. 544, P = 0. 024). Conclusions There is a negative correlation between eNOS expression and atherosclerosis development, which suggests that the reversal effect of pravastatin on atheroselerosis progression and plaque formation may relate to the expression of platelet derived eNOS.     

Tissue factor and nitric oxide: a controversial relationship!

Tissue factor (TF) is the primary physiological initiator of blood coagulation. TF has a high-affinity for factor (F) VII resulting in the formation of (TF:FVII:FVIIa) bimolecular complex which, in the presence of Ca(2+), increases the enzymatic activity of FVIIa towards its natural substrates, FIX and FX, generating their active forms FIXa and FXa, respectively. This eventually leads to thrombin generation and a fibrin clot formation. Up-regulation of TF in injured blood vessels and atherosclerotic plaque can lead to undesirable vascular thrombosis. Nitric oxide (NO) is a free radical synthesized from L-arginine and molecular oxygen by nitric oxide synthases (NOS). NO participates in diverse physiological and pathophysiological process as an intra or extracellular messenger. A relationship between TF and NO has been proposed. Thus, models of TF regulation by NO has been studied in different cells and experimental animal models, but the results have been conflicting. The premise that NO donors can prevent TF expression in vivo has provided the foundation for a broad field of pharmacotherapeutics in vascular medicine. A new class of drugs combining a statin (inhibitors of coenzyme A reductase) with an NO-donating moiety has been described. The resulting drug, nitrostatin, has been suggested to increase the antithrombotic effects of native statin. However, it is questionable if NO release from these drugs had any significant role on TF inhibition. In summary, care must be taken in drawing conclusions about the relationship between NO and TF. Interpretation of NO studies must take several factors into consideration, including NO bioavailability, its half-life and inactivation, as well as the cell type and experimental model used.     

大鼠组织一氧化氮含量变化及其调节在衰老过程中的作用

目的　揭示大鼠组织一氧化氮 ( NO)含量和一氧化氮合酶 ( NOS)活性变化与衰老的相关关系 ,并通过调节 NO合成 ,探讨 NO在衰老过程中的作用。　方法　对不同月龄大鼠采用铜离子活化镉还原法测定组织 NO含量 ,应用血红蛋白氧化法测定组织 NOS的活性 ,采用硫代巴比妥酸染色法测定组织丙二醛 ( MDA)含量。　结果　与青年组相比 ,老年组 ( 2 0～ 2 2月龄 )心脑肾组织 NO降低有显著性 ( P<0 .0 1 ) ,而中年组仅肾组织 NO含量降低有显著性 ( P<0 .0 5) ;老年组较中年组仅心脏组织 NO含量降低有显著性 ( P<0 .0 1 )。中年组心脑组织 NOS活性较青年组降低 ( P<0 .0 5) ;而老年组组织 NOS活性较中年组增高 ,仅脑组织 NOS增高有显著性 ( P<0 .0 5)。与老年对照组比较 ,β-雌二醇组心肝肾脑组织 NO含量明显增高 ( P<0 .0 1 ) ,而心脑肾组织 MDA下降有显著性 ( P<0 .0 1 ) ;L-硝基精氨酸甲酯组肝组织 NO降低有显著性 ( P<0 .0 5) ,而 MDA下降仅在脑组织有显著性 ( P<0 .0 5)。　结论　大鼠组织 NO含量与衰老之间存在一定的相关关系。     

动脉粥样硬化家兔主动脉壁与红细胞L-精氨酸/一氧化氮系统变化

目的 观察动脉粥样硬化时主动脉与循环中红细胞L－精氨酸（L－Arg）／一氧化氮（ＮＯ）系统变化的关系。方法 建立动脉粥样硬化模型，喂养家兔１２只，分为动脉粥样硬化组（ＡＳ组）和对照组，分别喂以高脂饮食和普通饮食，６周后取静脉血，并处死动物，测定主动脉和循环中红细胞Ｌ－Ａrg转运，一氧化氮合酶（ＮＯＳ）活性及一氧化氮生成量。结果 动脉粥样硬化主动脉平滑肌细胞Ｌ－Ａrg/NOS/NO系统活性增强，而其内皮细胞ＮＯＳ活性降低；循环中红细胞Ｌ－Ａrg的跨膜转运速率和亲和力降低，其ＮＯＳ活性下降。结论 循环中红细胞Ｌ－Ａrg／ＮＯ系统变化可能是动脉粥样硬化的表现之一，其有可能成为动脉粥样硬化发生发展的检测指标。