淫羊藿苷对模拟高原环境下雄性大鼠生殖系统损伤的保护作用研究

目的 研究淫羊藿苷对模拟高原环境下雄性大鼠生殖系统损伤的保护作用,并初步探讨相关作用机制。方法 选取30只12周龄雄性Wistar大鼠,随机分为平原对照组、高原模型组以及淫羊藿苷实验组,每组10只。平原对照组饲养于本院动物实验中心(海拔1 400 m),高原模型组以及淫羊藿苷实验组置入模拟海拔高度6 000 m高原环境动物实验舱;淫羊藿苷实验组给予100 mg/kg淫羊藿苷悬浊液于每日上午9时舱内灌胃,其余两组给予等体积生理盐水灌胃。模拟高原环境干预满30 d后麻醉取材,睾丸组织称重后一侧多聚甲醛固定用于进行苏木素-伊红(HE)染色观察大鼠睾丸组织形态学改变,一侧破碎匀浆处理用于检测超氧化物歧化酶(SOD)、丙二醛(MDA)氧化应激指标检测;附睾尾制备成精子悬液,检测精子质量。取大鼠血清检测睾酮(T)、黄体生成素(LH)、卵泡刺激素(FSH)等激素水平。结果 (1)高原模型组与淫羊藿苷实验组的体重增长显著低于平原对照组(P<0.05),且高原模型组睾丸指数显著低于平原对照组与淫羊藿苷实验组(P<0.05)。(2)HE染色结果示,高原模型组睾丸组织生精小管内各级生精细胞排列不...     

淫羊藿苷对大鼠骨折模型愈合及转化生长因子β1、血管内皮生长因子和骨形态发生蛋白-7表达的影响

目的:探讨淫羊藿苷对大鼠骨折模型的愈合作用及转化生长因子β1(TGF-β1)、血管内皮生长因子(VEGF)和骨形态发生蛋白-7(BMP-7)表达的影响.方法:将45只成年SPF级雄性SD大鼠均分为模型组(model组)、淫羊藿苷低剂量组(ICA-L组)和淫羊藿苷高剂量组(ICA-H组),每组都建立骨折模型;X线片观察各...     

淫羊藿次苷Ⅰ及淫羊藿次苷Ⅱ通过BMP/Runx2/Osx信号通路促进大鼠骨髓间充质干细胞成骨分化的实验研究

目的观察淫羊藿次苷Ⅰ及淫羊藿次苷Ⅱ对大鼠骨髓间充质干细胞(bone marrow stromal cells,BMSCs)成骨分化过程中BMP-2/Runx2/Osx信号通路的影响,探讨其可能的作用机制。方法贴壁筛选法体外培养BMSCs,随机分为空白对照组、阳性转化液组、抑制剂组、淫羊藿次苷Ⅰ组及淫羊藿次苷Ⅰ+抑制剂组、淫羊藿次苷Ⅱ组及淫羊藿次苷Ⅱ+抑制剂组。通过茜素红染色,对各组促进骨髓间充质干细胞向成骨细胞分化作用进行药效学评价; ELISA法检测各组ALP活性、BGP、COL-Ⅰ、BMP2蛋白分泌量;RTReal-TimePCR法检测各组ALP、BGP、Osterix和Runx-2 mRNA基因表达。结果茜素红染色结果表明,淫羊藿次苷Ⅰ组及淫羊藿次苷Ⅱ组均可明显观察到大量的矿化结节的形成;ELISA实验结果表明,与空白对照组比较,淫羊藿次苷Ⅰ及淫羊藿次苷Ⅱ均能明显促进ALP细胞活性及BGP、COL-Ⅰ、BMP-2蛋白分泌量,并且差异具有统计学意义(P0.05);两组药物作用强度均已达到阳性转化液组的80%以上。同时,淫羊藿次苷Ⅰ对ALP活性、 BGP蛋白表达均明显强于淫羊藿次苷Ⅱ,并且差异具有统计学意义(P0.05);对COL-Ⅰ、BMP-2的蛋白表达量,两者差异无统计学意义(P0.05)。RT-PCR实验结果表明,与空白对照组相比,淫羊藿次苷Ⅰ及淫羊藿次苷Ⅱ均可显著上调成骨相关转录因子ALP、BGP、RunX2,并进一步调节其下游基因Osterix的转录表达,差异具有统计学意义(P0.05);与阳性对照液组比较,淫羊藿次苷Ⅱ对ALP、Osterix的mRNA表达无明显差异(P0.05);淫羊藿次苷Ⅰ与淫羊藿次苷Ⅱ组比较,淫羊藿次苷Ⅱ对Osterix mRNA的表达明显强于淫羊藿次苷Ⅰ,并且差异具有统计学意义(P0.05)。对ALP、BGP、RunX2 mRNA的表达二者无显著性差异(P0.05)。结论淫羊藿次苷Ⅰ和淫羊藿次苷Ⅱ均能促进BMSCs定向成骨转化,其作用机制可能与激活BMP/Runx2/Osx信号通路有关。淫羊藿次苷Ⅰ和淫羊藿次苷Ⅱ作用差异可能与淫羊藿次苷Ⅰ在体内生物转化为淫羊藿次苷Ⅱ有关。     

淫羊藿苷保护脑死亡大鼠肾损伤的作用及机制研究

目的探讨淫羊藿苷对脑死亡大鼠肾损伤的保护作用及其作用机制。方法 30只SD大鼠被随机分为3组,每组各10只,分别为脑死亡组、治疗组和假手术组。脑死亡组大鼠在诱导脑死亡后不接受任何治疗;治疗组大鼠在诱导脑死亡后腹腔注射淫羊藿苷,剂量为100 mg/kg;假手术组保持颅内压正常并在麻醉状态下接受机械通气6 h。脑死亡组和治疗组分别在诱导脑死亡6 h后处死大鼠,假手术组在机械通气6 h后处死大鼠,分别取血清和肾组织进行检测。计量资料以均数±标准差(x±s)表示,采用单因素方差分析比较3组大鼠血清肌酐、尿素氮、Paller评分、CD68+巨噬细胞计数、促炎因子(IL-1β、IL-6、TNF-α)及趋化因子(MCP-1、IP-10)的转录水平,组间两两比较采用LSD法。P0.05为差异有统计学意义。结果淫羊藿苷治疗组脑死亡大鼠血清尿素氮和血清肌酐水平明显降低,分别为(10.0±1.5)、(92±12)mmol/L,与其他两组比较差异均有统计学意义(P均0.05);组织病理学示肾小管损伤评分明显降低,透射电镜示线粒体和内质网损伤减轻。淫羊藿苷可明显降低脑死亡大鼠肾组织内促炎因子(IL-1β、IL-6、TNF-α)和趋化因子(MCP-1、IP-10)的转录水平及CD68+巨噬细胞浸润,并明显降低c-Jun氨基末端激酶、p38丝裂原活化蛋白激酶和信号传导与转录激活因子3蛋白质磷酸化水平。结论淫羊藿苷能减轻脑死亡大鼠肾损伤,保护肾功能,可能通过抑制炎性反应和SAPK、JAK-STAT信号通路发挥作用。     

淫羊藿次苷Ⅱ对大鼠阴茎海绵体压力、平均动脉血压的影响及其作用机制的研究

目的 淫羊藿次苷Ⅱ是淫羊藿中提取分离的单体,为了解淫羊藿次苷Ⅱ对阴茎性功能障碍(ED)的疗效,通过体内试验观察其对阴茎海绵体压力和平均动脉血压的影响及作用机制.方法 麻醉下游离大鼠左侧颈总动脉和左侧阴茎海绵体,允别插管与电生理仪连接;游离左侧海绵体神经(CN),采用电生理仪刺激器连接双极电极刺激;检测不同浓度的淫羊藿次苷Ⅱ在刺激CN后对阴茎海绵体压力(ICP)和平均动脉血压(MAP)影响,淫羊藿苷、西地那非、罂粟碱作为对照组.同时观察可溶性环鸟苷酸(sGC)抑制剂H-[1,2,4]噁二唑[4,3.A]喹喔啉(ODQ)、一氧化氮合酶(NOS)抑制剂N~ω硝基-L-精氨酸(LNNA)及一氧化氮生成抑制剂亚甲蓝(methylene blue,MB)对淫羊藿次苷Ⅱ(10~(-4)mol/L)诱发ICP/MAP变化的影响.结果 4组药物均剂量依赖性显著提高ICP(P<0.01),淫羊藿次苷Ⅱ、淫羊藿苷和西地那非对MAP无显著影响(P>0.05),而罂粟碱浓度达10~(-4)mol/L后,即可显著降低MAP(P<0.01).在受试浓度下,LNNA、MB和ODQ可显著抑制淫羊藿次苷Ⅱ诱发的ICP变化(P<0.01),对两地那非诱发的ICP变化无影响(P>0.05).结论 淫羊藿次苷Ⅱ和淫羊藿苷呈剂量依赖性地提高大鼠阴茎勃起功能(ICP),淫羊藿次苷Ⅱ效价强度为淫羊藿苷的2.44倍,对平均动脉血压没有显著影响,其机制可能与增强阴茎海绵体NO-cGMP通路的活性有关.     

淫羊藿对骨质疏松型骨折局部骨形成蛋白mRNA表达的影响

目的 研究淫羊藿对骨质疏松型骨折局部骨形成蛋白-2(Bone morphogenetic protein-2,BMP-2)表达的影响.方法 取4月龄雌性大鼠78只,随机分成实验组(切除双侧卵巢)57只,对照组(切除卵巢周围少许脂肪组织)21只,术后10周,电镜观察证实实验组骨质疏松动物模型已制备成功后,取实验组54只及对照组18只大鼠,制作右侧股骨远端骨折,共分为4组,即:(1)磷酸钙骨水泥(Calcium Phosphate Cement,CPC)治疗组(简称A 组);(2)CPC-淫羊藿复合物治疗组(以下简称C组);(3)CPC+口服淫羊藿组(简称B组);(4)非骨质疏松组(简称D组)分别于术后第4、8、12周行实时荧光定量RT-PCR检测骨折局部BMP-2 mRNA的表达.结果 实验组各时间点BMP-2的mRNA表达水平均低于非骨质疏松组,但淫羊藿治疗组第4、8周的表达量高于CPC组,其中尤以CPC-Y组增高明显.结论 局部应用淫羊藿能更为有效诱导骨质疏松型骨折局部内源性BMP-2mRNA的表达.     

锶盐联合淫羊藿苷对大鼠骨髓基质干细胞成骨及成脂分化影响的研究

[目的]探索锶盐联合淫羊藿苷对超生理剂量糖皮质激素作用下大鼠骨髓基质干细胞(mesenchymal stem cells,MSCs)成骨、成脂分化的影响,并探讨Wnt/β-catenin信号通路在其中的调控作用。[方法]采用全骨髓培养法获取1周龄SD大鼠乳鼠MSCs,传至第3代时分为对照组、激素(终浓度:10-6mol/L)组、激素+淫羊藿苷(终浓度:10μg/L)组、激素+雷奈酸锶(终浓度:3 mmol/L)组及激素+淫羊藿苷+雷奈酸锶组。培养满21 d后进行HE、油红O、茜素红及ALP染色检测,RT-PCR检测Wnt信号通路相关因子(DKK-1、Wnt7b、GSK-3β、β-catenin、Runx-2和PPAR-γ2)基因的mRNA相对表达量。所有实验重复3次。[结果]所有组的细胞培养至21 d后,油红O染色结果显示激素组低倍镜下出现片状红染区,高倍镜下可见红染圆形脂滴,明显多于其他组;茜素红染色结果显示激素组未见明显紫红色阳性区域,而其他组可见片状阳性区域,由集落为中心放射性向四周生长,明显多于激素组,且联合组的阳性结果更明显;ALP染色结果显示激素组未见明显紫色阳性区域,而其他组可见片状阳性区域,明显多于激素组;RT-PCR结果显示激素组的Wnt相关因子(Wnt7b、GSK-3β和β-catenin)及成骨相关因子Runx-2显著低于其他组(P0.05),而激素组的Wnt信号通路特异性抑制因子DKK-1及成脂相关因子PPAR-γ2显著高于其他组(P0.05)。[结论]超生理剂量地塞米松可以通过抑制Wnt信号通路,诱导MSCs成脂分化,抑制其成骨分化,这可能与激素诱发股骨头坏死的发生、发展密切相关。而淫羊藿苷及锶盐可以在一定程度上减少超生理剂量糖皮质激素对Wnt信号通路的抑制作用,进而促进MSCs成骨分化、抑制其成脂分化,且二者联合应用的效果更好,这为研究激素性股骨头坏死早期防治提供了新的思路及方法。     

中药单体及其组方对~(60)Co-γ致小鼠生精功能障碍的治疗

目的:依据现代中医理论,选择白藜芦醇、枸杞多糖、淫羊藿苷组成新的方剂,研究中药单体及其组方对60Co-γ致小鼠生精功能障碍的治疗作用。方法:105只雄性昆明小鼠随机分为7组,每组15只,A组正常饲喂,B、C、D、E、F、G组以60Co-γ6Gy和4Gy间隔7d两次全身均匀照射,1周后C、D、E、F、G组分别给予白藜芦醇悬液、白藜芦醇+枸杞多糖混悬液、白藜芦醇+淫羊藿苷混悬液、白藜芦醇+枸杞多糖+淫羊藿苷组方混悬液、白藜芦醇+枸杞多糖+淫羊藿苷+L-肉碱组方混悬液各80mg/(kg.d)灌胃60d,记录小鼠每天的一般状况、体征及体重变化,于灌胃结束24h后处死,测量小鼠体重和双侧睾丸重量,并计算睾丸指数;酶联免疫法测定血清FSH、LH、T和E2水平并计算T/E2比值;行睾丸组织学观察。结果:放射线损伤引起睾丸指数下降,灌药后有所恢复,以E、F、G组恢复较好;枸杞多糖对小鼠血清FSH、LH、T具有明显促进作用;淫羊藿苷能增加小鼠的血清T值,对睾丸增重有直接作用;E、F、G组能增加T/E2水平;各灌药组以F组效果最佳,能使小鼠紊乱的生殖内分泌水平恢复正常,使损伤的睾丸重新恢复生精功能。结论:中药单体组方制剂对60Co-γ导致的小鼠生精功能障碍治疗有效,且以白藜芦醇+枸杞多糖+淫羊藿苷组方混悬液组最佳。     

淫羊藿苷与睾酮治疗亚急性衰老雄性大鼠的实验研究

目的观察淫羊藿苷及睾酮对D-半乳糖所致亚急性衰老大鼠血清SOD活性、T、E2含量,睾丸组织P16蛋白表达与细胞凋亡的影响。方法随机将40只SD成年雄性大鼠分为正常对照组、模型组、淫羊藿组、睾酮组。检测各组大鼠血清SOD活性、T、E2含量,HE染色观察睾丸组织变化,SP法观察睾丸组织P16蛋白表达情况,TUNEL法检测睾丸生殖细胞凋亡情况。结果D-半乳糖致亚急性衰老大鼠血清SOD活性、T含量下降,与正常组比较差异显著(P<0．01,P<0．01);各组E2变化无统计学意义。睾丸组织出现退行性变化,睾丸生殖细胞P16阳性细胞百分率(PI)和凋亡指数增加,较正常组差异显著(P<0．01);淫羊藿组和睾酮组SOD活性增加,T水平升高,生殖细胞凋亡指数下降,较模型组差异显著,睾丸组织的退行性变化明显改善。淫羊藿组生殖细胞P16阳性细胞百分率较模型组差异显著(P<0．01),而睾酮组变化无显著意义。结论与睾酮相比,淫羊藿不仅可以提高亚急性衰老雄性大鼠血清SOD活性和雄激素水平,减少生殖细胞凋亡,改善睾丸组织的退行性变化,还可通过抑制生殖细胞衰老基因P16蛋白表达这一途径延缓性腺衰老。     

Erythropoietin increases asymmetric dimethylarginine in endothelial cells: role of dimethylarginine dimethylaminohydrolase

Recombinant human erythropoietin therapy frequently causes hypertension in humans and animals with chronic renal failure. Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide (NO) synthase, and its accumulation has been associated with reducing NO bioavailability and increasing superoxide generation. Whether epoetin beta (EPO) or darbepoetin alpha (NESP) can modify the levels of ADMA in endothelial cells was investigated. Endothelial cells from the third passage were incubated for 24 h in the presence of various concentrations of EPO or NESP (0, 0.1, 1, 10, 50, 100, and 200 U/ml). The levels of ADMA, allantoin, nitrate, and nitrite in conditioned media and the activity of dimethylarginine dimethylaminohydrolase (DDAH), the content of thiols and reactive oxygen species in endothelial cells, were determined. When endothelial cells were exposed to EPO or NESP, ADMA concentration in the cell culture medium increased significantly in a dose-dependent manner versus control. This effect was associated with a reduced activity of DDAH, the enzyme that degrades ADMA. Furthermore, EPO- or NESP-induced accumulation of ADMA was accompanied by a significant reduction of NO synthesis and an increase in oxidative stress. Both allantoin, a marker of oxygen free radical generation, and reactive oxygen species increased significantly after EPO or NESP treatment compared with control. The antioxidant pyrrolidine dithiocarbamate preserved DDAH activity and reduced ADMA accumulation in the same way as the co-incubation with anti-EPO neutralizing antibody. EPO and NESP posttranslationally impair DDAH activity via increased oxidative stress, causing ADMA as an important cardiovascular risk factor to accumulate and inhibit NO synthesis.     

Association between cerebrospinal fluid levels of asymmetric dimethyl-L-arginine, an endogenous inhibitor of endothelial nitric oxide synthase, and cerebral vasospasm in a primate model of subarachnoid hemorrhage

OBJECT: Decreased availability of nitric oxide (NO) has been proposed to evoke delayed cerebral vasospasm after sub-arachnoid hemorrhage (SAH). Asymmetric dimethyl-L-arginine (ADMA) inhibits endothelial NO synthase (eNOS) and, therefore, may be responsible for decreased NO availability in cases of cerebral vasospasm. The goal of this study was to determine whether ADMA levels are associated with cerebral vasospasm in a primate model of SAH. METHODS: Twenty-two cynomolgus monkeys (six control animals and 16 with SAH) were used in this study. The levels of ADMA, L-arginine, L-citrulline, nitrites, and nitrates in cerebrospinal fluid (CSF) and serum were determined on Days 0, 7, 14, and 21 following onset of SAH. Cerebral arteriography was performed to assess the degree of vasospasm. Western blot analyses of the right and left middle cerebral arteries (MCAs) were performed to assess the expression of eNOS, type I protein-arginine methyl transferase (PRMT1) and dimethylarginine dimethylaminohydrolase (DDAH2). Cerebrospinal fluid levels of ADMA remained unchanged in the control group (six animals) and in animals with SAH that did not have vasospasm (five animals; p = 0.17), but the levels increased in animals with vasospasm (11 animals) on Day 7 post-SAH (p < 0.01) and decreased on Days 14 through 21 (p < 0.05). Cerebrospinal fluid levels of ADMA correlated directly with the degree of vasospasm (correlation coefficient = 0.7, p = 0.0001; 95% confidence interval: 0.43-0.83). Levels of nitrite and nitrate as well as those of L-citrulline in CSF were decreased in animals with vasospasm. Furthermore, DDAH2 expression was attenuated in the right spastic MCA on Day 7 post-SAH, whereas eNOS and PRMT1 expression remained unchanged. CONCLUSIONS: Changes in the CSF levels of ADMA are associated with the development and resolution of vasospasm found on arteriograms after SAH. The results indicate that endogenous inhibition of eNOS by ADMA may be involved in the development of delayed cerebral vasospasm. Inhibition of ADMA production may provide a new therapeutic approach for cerebral vasospasm after SAH.     

Handling of asymmetrical dimethylarginine and symmetrical dimethylarginine by the rat kidney under basal conditions and during endotoxaemia.

BACKGROUND: Asymmetrical dimethylarginine (ADMA) is capable of inhibiting nitric oxide synthase enzymes, whereas symmetrical dimethylarginine (SDMA) competes with arginine transport. The potential role of inflammation in the metabolism of ADMA has been elucidated in an in vitro model using tumour necrosis factor-alpha, resulting in a decreased activity of the ADMA-degrading enzyme dimethylarginine dimethylaminohydrolase (DDAH). The kidney probably plays a crucial role in the metabolism of ADMA by both urinary excretion and degradation by DDAH. We aimed to further elucidate the role of the kidney in a rat model under basal conditions and during endotoxaemia. METHODS: Twenty-five male Wistar rats weighing 275-300 g were used for this study. The combination of arteriovenous concentration differences and kidney blood flow allowed calculation of net organ fluxes. Blood flow was measured using radiolabelled microspheres according to the reference sample method. Concentrations of ADMA, SDMA and arginine were measured by high-performance liquid chromatography. RESULTS: The kidney showed net uptake of both ADMA and SDMA and fractional extraction rates were 35% and 31%, respectively. Endotoxaemia resulted in a lower systemic ADMA concentration (P = 0.01), which was not explained by an increased net renal uptake. Systemic SDMA concentrations increased during endotoxaemia (P = 0.007), which was accompanied by increased creatinine concentrations. CONCLUSIONS: The rat kidney plays a crucial role in the regulation of concentrations of dimethylarginines, as both ADMA and SDMA were eliminated from the systemic circulation in substantial amounts. Furthermore, evidence for the role of endotoxaemia in the metabolism of dimethylarginines was obtained as plasma levels of ADMA were significantly lower in endotoxaemic rats.     

Human recombinant erythropoietin augments serum asymmetric dimethylarginine concentrations but does not compromise nitric oxide generation in mice.

BACKGROUND: Patients with advanced chronic renal disease (CRD) suffer from excessive morbidity and mortality due to complications of accelerated atherosclerosis. Recombinant human erythropoietin (EPO), which is routinely used to treat the anaemia present in approximately 90% of dialysis-dependent patients with end-stage renal disease, may induce vascular dysfunction by reducing nitric oxide (NO) availability. Pathophysiologic concentrations of asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase (NOS), are found in patients with CRD and correlate with vascular disease and cardiovascular mortality. The aim of the current study was to investigate the effect of EPO on ADMA concentrations and NO generation in vitro and in vivo. Furthermore, we wanted to study the effect of EPO on the expression of the enzymes that regulate ADMA metabolism and NO generation. METHODS: Human umbilical vein endothelial cells (HUVECs) were exposed to therapeutic concentrations of EPO. The expression and metabolic activity of dimethylarginine dimethylaminohydrolase II (DDAH II), the enzyme that degrades ADMA, was evaluated. Following subcutaneous administration of EPO to Balb/c mice for 10 weeks, serum ADMA concentrations were determined. Systolic blood pressure was measured noninvasively. Urinary nitrite and nitrate (NOx) concentrations were assessed by Griess assay. Protein expression of DDAH and NOS in livers and kidneys was measured by western blotting. RESULTS: EPO suppressed ADMA elaboration by HUVECs. Systolic blood pressure and serum concentrations of ADMA were significantly elevated in EPO-treated mice. The protein expression of DDAH I in the kidney and liver was upregulated while hepatic expression of DDAH II was decreased and renal DDAH II expression remained unchanged by EPO administration. However, EPO augmented urinary NOx concentrations as well as the expression of NOS 1 and NOS 2 in the kidney. CONCLUSION: In spite of elevating serum ADMA concentrations, EPO does not appear to compromise overall NO generation in Balb/c mice.     

Effect of DDAH/ADMA/NOS regulation pathway on cavernae corporum cavernosorum rat penis of different age

The effect of DDAH/ADMA/NOS pathway in penile tissue of rats of different age was investigated to better understand the mechanism of age‐related erectile dysfunction (ED). The Sprague Dawley male rats were assigned as the young group (3 month old, n = 10) and the old group (18 month old, n = 10) respectively. Intracavernous pressure (ICP) was measured before and after papaverine intracavernous injection. Pathology structure of penile tissue was evaluated under transmission electron microscope. The expression amounts of asymmetric dimethylarginine (ADMA) and cyclic guanosine monophosphate (cGMP) in penile tissue were detected by ELISA; the expression levels of isoform‐specific DDAH and NOS were assessed via Western blot. Compared with the young group, the ICP in the old group rat decreased significantly (33.46 ± 5.37 versus 39.71 ± 3.67 mmHg, P = 0.02) after papaverine injection. Diffused fibrosis and impairment of endothelial cell were observed in corpus cavernosum in the old group rats. Higher level of ADMA (10.83 ± 0.96 versus 7.51 ± 1.39 μmol per gpro, P = 3.14 × 10^?4) and lower level of cGMP (29.42 ± 3.84 versus 47.09 ± 6.07 nmol per gpro, P = 1.57 × 10^?6) were detected in penile tissue of the old group compared with those of the young group. Expression of DDAH1, DDAH2, endothelial NOS (eNOS) and neuronal NOS(nNOS) all decreased significantly in penile tissue of the old group rat. The DDAH/ADMA/NOS regulation pathway changes dramatically accompanying with lower ICP in old group rat compared with those of the young group. Such findings in rats are suggestive in understanding the mechanism of age‐related ED in humans.     

Intravenous N-acetylcysteine during hemodialysis reduces asymmetric dimethylarginine level in end-stage renal disease patients

AIM: Cardiovascular disease is the main cause of mortality in chronic kidney disease patients. Moreover, uremic patients are in a pro-oxidant state and show an increase in asymmetric dimethylarginine (ADMA) levels due to inhibition of the enzyme dimethylarginine dimethylaminohydrolase (DDAH). Asymmetric dimethylarginine per se seems responsible for a 52% increase in the risk of death and for a 34% increase in the risk of cardiovascular events in dialysis patients. N-acetylcysteine (NAC) is a thiol molecule that has direct and indirect antioxidant effects which decrease reactive oxidant species and increase the bioavailability of the DDAH enzyme. The aim of the current study was to determine the effect of intravenous NAC on plasma ADMA level when administered during hemodialysis in end-stage renal disease (ESRD) patients. MATERIALS AND METHODS: 40 patients with ESRD were randomized to receive a 4-hour intravenous infusion of NAC or placebo during a 4-hour hemodialysis session. There were 3 diabetic patients (15%) in the treatment group and 6 patients in the control group. Plasma ADMA levels were measured before and immediately after hemodialysis. Hemodynamic parameters, including pulse pressure, were also measured. The paired t-test was used to compare the difference of ADMA levels before and after hemodialysis in each group, while the independent t-test was used to compare the difference of ADMA levels between the groups. RESULTS: Compared with the pre-dialysis condition, there was a decrease of ADMA level in the control group (1.1253 +/- 0.1797 microM to 0.8676 +/- 0.1449 microM) (p < 0.001), and in the NAC group (1.1522 +/- 0.1737 microM to 0.7844 +/- 0.1586 microM) (p < 0.001). Compared with hemodialysis alone, NAC had a greater lowering effect on the ADMA level (21.3 vs. 31.9%, p < 0.05). CONCLUSION: N-acetylcysteine (NAC) administered intravenously during hemodialysis reduced asymmetric dimethylarginine (ADMA) levels more significantly than hemodialysis alone.     

血红素氧合酶2在慢性肾衰大鼠阴茎海绵体中的表达

目的:检测血红素氧合酶2(HO-2)在慢性肾衰(CRF)大鼠阴茎海绵体中的变化,探讨HO-2在阴茎勃起过程中的作用及与睾酮的关系。方法:采用10周龄雄性SD大鼠行5/6肾切除术构建CRF模型成功后,测定对照组(CTL组,n=15)、CRF组(n=15)平均颈动脉压(MAP)及海绵体内压最大值(ICPmax)、血清睾酮,并检测阴茎海绵体中eNOS、nNOS、HO-2的表达。结果:CRF组在3V、5V电刺激海绵体神经后ICPmax/MAP(0.121±0.084,0.135±0.088)均显著低于对照组(0.263±0.147,0.244±0.089,P<0.01),CRF组血清睾酮浓度[(1.190±0.946)nmol/L]显著低于对照组[(7.800±5.001)nmol/L,P<0.01],CRF组海绵体中nNOS、eNOS表达低于对照组,CRF组海绵体中HO-2表达(0.510±0.397)显著低于对照组(2.672±1.720,P<0.01),海绵体中HO-2表达下降与血清睾酮下降存在相关性(r=0.902,P<0.01)。结论:CRF组大鼠阴茎海绵体中nNOS、eNOS、HO-2、血清睾酮水平降低等可能是CRF并发勃起功能障碍机制之一。     

Low androgen status inhibits erectile function by up-regulating the expression of P2X receptors in rat corpus cavernosum

The aim of our study was to investigate whether low androgen level inhibits the erectile function of rats by regulating the expression of P2X receptors. Thirty-six 8-week-old male SD rats were randomly divided into six groups: sham-operated groups (4w-sham, 8w-sham), castration groups (4w-cast, 8w-cast) and androgen replacement after castration groups (4w-cast + T, 8w-cast + T). The maximum intracavernous pressure/mean arterial pressure (ICPmax/MAP), the levels of serum testosterone (T) and nitric oxide (NO), and the expression of P2X1, P2X2, P2X3, eNOS, p-eNOS, ROCK1 and ROCK2 in the cavernous tissue of rats were determined. The serum T, ICPmax/MAP and NO levels in penile corpus cavernosum in the castration groups were significantly lower than those in other groups (p < .01). The protein expression of P2X1, P2X2, P2X3, ROCK1 and ROCK2 in the castration groups was significantly higher than those in other groups (p < .01). P-eNOS/eNOS of the castration groups were significantly lower than those of other groups (p < .01). The serum T level was negatively correlated with the expression of P2X1, P2X2 and P2X3 in the corpus cavernosum. Low androgen level inhibits erectile function by up-regulating the expression of P2X1, P2X2, P2X3 and RhoA/Rho-kinase resulting in reducing the ratio of p-eNOS/eNOS and the level of NO in corpus cavernosum of rats.