生长激素补充对老龄大鼠勃起功能及阴茎海绵体nNOS表达的影响

目的探讨生长激素(GH)补充对老龄大鼠勃起功能及阴茎海绵体神经型一氧化氮合酶(nNOS)表达的影响。方法20只18月龄SD大鼠随机均分成A、B两组,10只2月龄SD大鼠为C组。A组给予GH1U/(kg·d),B、C组给予相同剂量的生理盐水,均皮下注射8周。于8周末观察阿朴吗啡(APO)皮下注射与大鼠海绵体内注射罂粟碱诱导的阴茎勃起情况,并用免疫组化SP法检测阴茎海绵体组织中nNOS神经纤维的数目。结果8周末时,A、C组大鼠APO诱导的勃起次数、海绵体内注射罂粟碱诱导的最大海绵体内压以及阴茎海绵体组织中nNOS神经纤维数目均显著高于B组(P<0.05或P<0.01)。结论老龄大鼠勃起功能及阴茎海绵体nNOS表达较成年大鼠明显下降,GH补充可以部分改善老龄大鼠的勃起功能,其机制之一可能与GH补充增加了老龄大鼠阴茎海绵体组织中nNOS神经纤维数目有关。     

负压吸引对糖尿病性ED大鼠阴茎海绵体组织一氧化氮合酶表达的影响

目的研究负压吸引对糖尿病性勃起功能障碍（ED）大鼠阴茎组织一氧化氮合酶（NOS）表达水平的影响。方法25只实验鼠中随机选取5只为正常对照组（A组）,其余火鼠用链脲左菌素和阿朴吗啡诱导建立Ⅰ型糖尿病性ED大鼠模型。之后把造模成功的糖尿病性ED大鼠随机分成糖尿病ED吸引组（B组）和糖尿病ED非吸引组（C组）。在B组大鼠负压吸引治疗结束后将A、B、C3组大鼠处死并取阴茎组织进行石蜡包埋。采用免疫组织化学方法检测各组大鼠阴茎组织中三种一氧化氮合酶亚型（nNOS、eNOS、iNOS）的表达情况。结果A组大鼠阴茎组织中nNOS蛋白表达水平高于B组和C组（均P〈0.001）;A组和B组大鼠阴茎组织中eNOS蛋白表达水平高于C组（均P〈0.01）;A组iNOS蛋白表达水平低于B组和C组（P〈0.01,P〈0.001）,同时B组iNOS蛋白表达水平低于C组（P〈0.01）;剩余其他各组间的比较差异无统计学意义（P〉0.05）。结论负压吸引可以通过升高阴茎组织中的eNOS和降低iNOS的表达来改善勃起功能。     

伊木萨克片对半去势雄性大鼠勃起功能的影响

目的 研究伊木萨克片对半去势雄性大鼠勃起功能的影响.方法 从60只性功能正常的雄性SD大鼠中随机取出10只为正常对照组,余50只行右侧睾丸摘除后随机分为半去势空白组、男宝对照组、伊木萨克低、中、高剂量组,经药物干预6周后行阿朴吗啡(Apomorphine,APO)勃起试验,镜检阴茎海绵体的形态改变,采用免疫组化SP法检测各组大鼠阴茎组织中nNOS、eNOS蛋白表达.结果 (1)半去势空白组勃起潜伏期显著长于正常对照组(P<0.01),伊木萨克低、中、高剂量组勃起潜伏期显著短于半去势空白组和男宝对照组(P<0.05),但长于正常对照组(P<0.05),伊木萨克片低、中、高剂量组之间差异则无统计学意义(P>0.05):(2)半去势空白组阴茎组织中eNOS、nNOS蛋白表达低于正常对照组(P<0.05).伊木萨克低、中、高剂量组大鼠阴茎组织中eNOS、nNOS蛋白表达均显著高于半去势空白组和男宝对照组(P<0.05),其中eNOS在伊术萨克片中剂量组显著高于正常对照组(P<0.01),而伊木萨克片低、高剂量组与正常对照组之间的差异则无统计学意义(均为P>0.05);nNOS在伊木萨克片低、中、高剂量组与正常对照组及伊木萨克片低、中、高剂量组之间差异无统计学意义(P>0.05).结论 (1)半去势可显著影响雄性大鼠的阴茎勃起功能;(2)伊木萨克片干预后能够显著增强半去势大鼠的阴茎勃起功能,其机制可能和增加阴茎组织中eNOS、nNOS蛋白表达有关.     

肺纤维化对大鼠阴茎勃起功能的影响

目的:研究肺纤维化对大鼠勃起功能的影响及其机制。方法:12周雄性SD大鼠40只,随机分为4组:正常对照4周组(A组)、6周组(B组)和肺纤维化大鼠4周组(C组)、6周组(D组)各10只,分别用生理盐水(A、B组)及博莱霉素(5 mg/kg)气管内注入,饲养4周(A、C组)、6周(B、D组)后,测定大鼠血清睾酮、动脉血气分析、阴茎海绵体内压/平均颈动脉压(ICP/MAP),取阴茎标本测定NOS活性及cGMP含量,实时荧光PCR检测eNOS、iNOS和nNOS的mRNA在阴茎海绵体的表达,W estern印迹检测阴茎海绵体eNOS蛋白的表达。结果:电刺激的3 V,5 V C组ICP/MAP×100(16.37±2.19,27.19±3.18)较A组(30.78±2.66,50.09±6.97)显著降低(P<0.05),D组ICP/MAP×100,3 V,5 V(10.17±1.31,17.40±1.74)较B组(31.45±3.07,51.23±7.23)显著降低(P<0.05),D组ICP/MAP×100值较C组显著降低(P<0.05)。C组PaO2(75.50±13.87)mmHg较A组(103.80±6.88)mmHg显著降低(P<0.05),D组PaO2(83.60±5.50)mmHg较B组(102.70±5.77)mHg显著降低(P<0.05)。C组血清睾酮水平(391.1±264.7)ng/d l较A组(175.9±53.0)ng/d l显著升高(P<0.05),D组血清睾酮水平(745.4±408.8)ng/d l较B组(177.8±52.3)ng/d l显著升高(P<0.05),同时D组血清睾酮水平较C组显著升高(P<0.05)。C组NOS活性及cGMP含量[(1.50±0.14)U/mg prot,(35.69±3.64)pmol/mg]较A组[(2.66±0.39)U/mg prot,(51.10±7.22)pmol/mg]显著降低(P<0.05),D组NOS活性及cGMP含量[(1.40±0.20)U/mg prot,(34.55±4.30 pmol/mg)]较B组[(2.75±0.36)U/mg prot,(52.15±6.86)pmol/mg]显著降低(P<0.05),C组与D组比较NOS活性及cGMP含量无显著性差异(P>0.05)。C组eNOS蛋白表达量(0.79±0.01)较A组(0.87±0.01)显著降低(P<0.01),D组eNOS蛋白表达量(0.71±0.02)较B组(0.88±0.01)显著降低(P<0.05),D组较C组eNOS蛋白表达量显著降低(P<0.05)。C组eNOS mRNA表达量(4.46±0.92)较A组(2.61±0.68)显著升高(P<0.05),D组eNOS mRNA(2.79±0.60)表达量与B组(2.69±0.65)无显著性差异(P>0.05),nNOS及iNOS的mRNA表达量在A、B组与C、D组间均无显著性差异(P>0.05)。结论:肺纤维化可通过抑制阴茎海绵体eNOS蛋白的表达、降低总NOS活性及cGMP含量等机制抑制阴茎勃起功能。     

高脂及糖尿病性勃起功能障碍大鼠阴茎海绵体中eNOS和ET-1蛋白表达的研究

目的探讨高脂及糖尿病性勃起功能障碍大鼠阴茎海绵体中内皮型一氧化氮合酶(eNOS)和内皮素-1(ET-1)蛋白表达的变化及其可能的机制。方法 58只SPF级雄性SD大鼠随机分成3组:(1)对照组(n=14),普通饲料喂养;(2)高脂组(n=15),高脂饲料喂养24周后在原饲料配方中加入含0.2%硫氧嘧啶继续喂养;(3)糖尿病组(n=29),高脂饲料喂养24周后腹腔注射20mg/kg STZ;于实验开始后36周末,检测大鼠血糖、血清总胆固醇(TC)、甘油三脂(TG)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)、胰岛素水平;成模后用阿朴吗啡诱导并观察大鼠阴茎勃起功能变化;采用Western blot检测大鼠阴茎海绵体组织eNOS和ET-1蛋白表达。结果血糖、胰岛素、血脂检测结果显示成功建立了高脂和糖尿病模型。与对照组相比,高脂及糖尿病组大鼠勃起功能明显下降,eNOS蛋白表达显著降低,而ET-1显著升高(P0.05);与高脂组相比,糖尿病组eNOS与ET-1表达进一步失衡,且阴茎勃起功能障碍较高脂组加重。结论糖尿病和高脂血症导致勃起功能障碍的发病机制可能与阴茎海绵体组织内eNOS和ET-1表达失衡密切相关。     

杜仲对糖尿病大鼠扑捉行为和阴茎组织神经传导通路的影响

目的:探讨杜仲改善勃起功能的药效和病理学机制。方法:雄性糖尿病(DM)大鼠30只随机分为3组:A组(10只,DM大鼠赋形剂灌胃组)、B组(10只,DM大鼠西地那非灌胃组)、C组(10只,DM大鼠杜仲灌胃组)及10只正常对照组大鼠(赋形剂灌胃,D组);灌胃4周后观察4组大鼠扑捉行为,透射电镜检查阴茎组织有髓神经纤维超微特征;用免疫组化二步法显示阴茎组织中神经元型一氧化氮合酶(nNOS)的表达。结果:与A组比较,C组大鼠扑捉次数显著增多(P<0.05),阴茎组织中nNOS表达显著增强(P<0.001)。透射电镜显示:A组大鼠阴茎组织有髓神经纤维排布失序,部分变性、板层分离形成透明空泡或网络状,C组大鼠有髓神经纤维排列规整,板层结构清晰。结论:杜仲可通过减轻有髓神经的损伤、增强阴茎组织中nNOS表达改善ED。     

髂内动脉结扎对大鼠阴茎海绵体组织nNOS神经纤维及eNOS表达的影响

目的 研究髂内动脉结扎对大鼠阴茎海绵体组织神经型一氧化氮合酶(nNOS)神经纤维及内皮型一氧化氮合酶(eNOS)表达的影响。方法 45只Wistar雄性成年大鼠随机分为假手术组(21只)和手术组(24只)。其中手术组采用双侧髂内动脉结扎的方法制备动脉性勃起功能障碍(ED)大鼠模型,假手术组作为对照组只切开腹腔不结扎髂内动脉。于术后1周、3周、6周末分别取各组1/3大鼠,观察其勃起功能,并采用免疫组化SP法检测大鼠阴茎组织中nNOS神经纤维的数量及eNOS的表达。结果 手术组与假手术组相比,1周末、3周末和6周末在阴茎勃起次数和阴茎组织nNOS神经纤维数量及eNOS表达上均有显著差异(P<0.01)。手术组大鼠阴茎勃起次数3周末高于1周末,6周末高于3周末;eNOS的表达3周末明显低于1周末,而6周末高于3周末,差异均有显著性意义(P<0.001),并呈增加趋势。手术组大鼠阴茎组织nNOS神经纤维数量三者之间差异均有显著性(P<0.001),呈进行性下降。结论 髂内动脉结扎影响阴茎勃起功能和nNOS、eNOS的表达。阴茎组织中nNOS阳性神经纤维数量的减少,可能是髂内动脉结扎术后阴茎勃起功能障碍发生的原因之一。     

伊木萨克片对糖尿病性ED大鼠阴茎组织中eNoS和nNoS的影响

目的 研究维药伊木萨克片对DM性ED大鼠阴茎海绵体组织中eNOS和nNOS蛋白表达水平的影响.方法 取雄性SD大鼠70只,从中随机取10只为正常对照组,余60只以链脲佐菌素诱导建立DM模型后,行阿朴吗啡阴茎勃起实验筛选DM性ED模型,发生ED者随机分为DM性ED组、伊木萨克片组、胰岛素组、伊木萨克片 胰岛素(联用)组,未成DM者为STZ组.各组给药6周后,采用免疫组化SP法检测各组大鼠阴茎组织中eNOS、nNOS含量.结果 DM性ED组大鼠阴茎组织中eNOS、nNOS蛋白表达水平显著低于正常对照组(P＜0.01);伊木萨克片组、胰岛素组及联用组大鼠阴茎组织中eNOS、nNOS蛋白表达水平均显著高于DM性ED组(P＜0.01),但伊木萨克片组与胰岛素组显著低于联用组(P＜0.01, P＜0.01;P＜0.05,P＜0.01);STZ组与正常对照组之间的差异则无统计学意义(P＞0.05).结论 维药伊木萨克片可以显著提高DM性ED大鼠阴茎组织中eNOS、nNOS蛋白表达水平,并提示在胰岛素控制血糖的基础上效果可能更佳.     

糖尿病性勃起功能障碍大鼠阴茎海绵体组织中神经生长因子的表达及其治疗作用的研究

目的:本研究通过检测糖尿病性勃起功能障碍(ED)大鼠阴茎组织中神经生长因子(NGF)表达,并使用hNGF进行治疗,以探讨糖尿病性ED发病机制及NGF治疗作用的机制。方法:成年雄性SD大鼠60只,随机取50只大鼠用于制作糖尿病模型,饲养8周后,取正常组和糖尿病组大鼠阴茎海绵体组织,采用RT-PCR和W estern印迹法检测NGF的mRNA及蛋白水平。从造模成功的糖尿病大鼠中筛选出有ED大鼠,把所有大鼠分为5组:正常组、糖尿病性ED组、糖尿病性ED单用NGF组(NGF组)、糖尿病性ED单用胰岛素组(R I组)、糖尿病性ED联合应用NGF和胰岛素组(NGF+R I组,胰岛素通过颈部皮下注射给药,NGF通过腹腔内注射给药),8周后测海绵体内压(ICP),并取所有大鼠阴茎海绵体组织用免疫组化法观察nNOS神经纤维的变化。结果:与正常组相比,糖尿病性ED组大鼠阴茎海绵体组织中NGF的mRNA表达增加,蛋白含量增加。与糖尿病性ED组相比,NGF组、R I组、NGF+R I组ICP水平显著升高(P<0.05);NGF组、R I组、NGF+R I组阴茎组织中nNOS神经纤维水平显著升高(P<0.05)。结论:糖尿病晚期勃起神经出现损伤并发生ED,推测可能与NGF分泌增加的幅度小于高血糖状态对勃起神经的损伤程度有关,也可能与NGF与其相应受体结合转运能力损害有关,给予外源性NGF可能有助于糖尿病性ED局部神经病变减轻和勃起功能改善。提示NGF的异常在糖尿病性ED的发病及治疗中可能具有重要作用。     

大鼠前列腺增生模型阴茎海绵体内nNOS、eNOS表达研究

目的 分析引起阴茎勃起的主要神经递质NO合成的限速酶nNOS和eNOS在BPH模型大鼠阴茎海绵体中的表达.试探讨BPH引起ED的可能因素.方法 20只雄性SD大鼠随机分为正常对照组和BPH模型组.通过去势后丙酸睾酮注射建立BPH模型,10只老年大鼠为老年对照组.4周后处死大鼠,分析不同组前列腺湿质量与前列腺指数,并在光镜下观察前列腺组织病理学改变.应用免疫组化方法研究不同组间大鼠阴茎海绵体内nNOS和eNOS阳性表达情况并比较组间差异.结果 BPH模型组中前列腺湿质量和前列腺指数与正常对照组比较差异有统计学意义;显微镜下BPH模型组前列腺组织呈明显增生表现,大鼠BPH造模成功.免疫组化方法显示BPH模型组、老年对照组大鼠阴茎海绵体内的nNOS及eNOS阳性细胞表达率明显降低;nNOS及eNOS阳性表达与正常对照组的比较差异均有统计学意义.结论 nNOS及eNOS是调控阴茎勃起的神经递质NO合成的关键酶,BPH模型组的阴茎海绵体内nNOS、eNOS表达明显减少或活性降低,导致NO释放减少可能是BPH引起勃起功能障碍的重要原因.     

2型糖尿病大鼠血浆同型半胱氨酸与阴茎海绵体内NOS和内源性CO的相关性研究

目的:研究2型糖尿病性大鼠血浆同型半胱氨酸(Hcy)与阴茎海绵体内NOS和内源性CO的相关性。方法:选取3月龄雄性Wistar大鼠50只,随机选取10只为对照组(A组);高糖高脂饲料饲养4周后从其他40只大鼠中筛选出30只构建成功的糖尿病(DM)大鼠模型,随机分成3组:DM大鼠组(B组);胰岛素治疗组(C组)和叶酸+维生素B12治疗组(D组)。8周及12周后注射阿朴吗啡观察各组大鼠阴茎勃起情况。12周后测各组大鼠血浆总Hcy含量及阴茎海绵体内NOS活性和CO含量。结果:与A组比较,B组大鼠血浆Hcy浓度明显升高,阴茎勃起功能明显降低,阴茎海绵体NOS活性和CO含量均下降,差异有显著性(P<0.01)。2型DM大鼠中高Hcy血症发生率为55%。与B组比较,C组和D组中大鼠血浆Hcy浓度显著下降,阴茎勃起功能、阴茎海绵体NOS活性均升高(P<0.01),Hcy与NOS(rA=-0.89,rB=-0.76,rC=-0.91,rD=-0.91)及CO含量(rA=-0.82,rB=-0.77,rC=-0.93,rD=-0.81)均呈负相关。结论:2型DM大鼠血浆中的高Hcy可能是引起阴茎海绵体NOS活性下降、CO含量下降,进而导致DM ED发病的分子机制之一。胰岛素、叶酸和维生素B12可以改善DM大鼠的勃起功能,提高阴茎海绵体NOS活性和CO含量。     

Effects of icariin on erectile function and expression of nitric oxide synthase isoforms in castrated rats

Aim： To investigate the effect of icariin on erectile function and the expression of nitric oxide synthase （NOS） isoforms in castrated rats. Methods： Thirty-two adult male Wistar rats were randomly divided into one shamoperated group （A） and three castrated groups （B, C and D）. One week after surgery, rats were treated with normal saline （groups A and B） or oral icariin （1 mg/[kg·day] for group C and 5 mg/[kg·day] for group D） for 4 weeks. One week after treatment, the erectile function of the rats was assessed by measuring intracavernosal pressure （ICP） during electrostimulation of the cavernosal nerve. The serum testosterone （ST） levels, the percent of smooth muscle （PSM） in trabecular tissue, and the expression of mRNA and proteins of neuronal nitric oxide synthase （nNOS）, inducible nitric oxide synthase （iNOS）, endothelial nitric oxide synthase （eNOS） and phosphodiesterase V （PDES） in corpus cavernosum （CC） were also evaluated. Results： ICP, PSM, ST and the expression of nNOS, iNOS, eNOS and PDE5 were significantly decreased in group B compared with those in group A （P 〈 0.01）. However, ICE PSM and the expression of nNOS and iNOS were increased in groups C and D compared with those in group B （P 〈 0.05）. Changes in ST and the expression of eNOS and PDE5 were not significant （P 〉 0.05） in groups C and D compared with those in group B. Conclusion： Oral treatment with icariin （〉 98.6 % purity） for 4 weeks potentially improves erectile function. This effect is correlated with an increase in PSM and the expression of certain NOS in the CC of castrated rats. These results suggest that icariin may have a therapeutic effect on erectile dysfunction.     

Gene transfer of endothelial nitric oxide synthase partially restores nitric oxide synthesis and erectile function in streptozotocin diabetic rats

PURPOSE: We determined whether adenoviral gene transfer of endothelial nitric oxide synthase (eNOS) to the penis of streptozotocin induced diabetic rats could improve the impaired erectile response. MATERIALS AND METHODS: Two experimental groups of animals were transfected with adenoviruses, including streptozotocin (Sigma Chemical Company, St. Louis, Missouri) diabetic rats with AdCMVbetagal and streptozotocin diabetic rats with AdCMVeNOS. At 1 to 2 days after transfection these study animals underwent cavernous nerve stimulation to assess erectile function and their responses were compared with those of age matched control rats. In control and transfected streptozotocin diabetic rats eNOS and neuronal NOS (nNOS) were examined by Western blot analysis. Constitutive and inducible NOS activities were evaluated in the presence and absence of calcium by L-arginine to L-citrulline conversion and nitrate plus nitrite levels were measured. In control and streptozotocin diabetic penes beta-galactosidase activity and localization were determined. RESULTS: After transfection with AdCMVbetagal beta-galactosidase was localized to the endothelium and smooth muscle cells of the streptozotocin diabetic rat penis. Streptozotocin diabetic rats had a significant decrease in erectile function, as determined by peak and total intracavernous pressure (area under the curve) after cavernous nerve stimulation compared with control rats. Streptozotocin diabetic rats transfected with AdCMVeNOS had peak intracavernous pressure and area under the curve similar to those in control animals. This change in erectile function was a result of eNOS over expression with an increase in eNOS protein expression and constitutive NOS activity as well as an increase in nitric oxide biosynthesis, as reflected by an increase in cavernous nitrate plus nitrite formation. There was no change in nNOS protein expression or calcium independent conversion of NOS (inducible NOS activity). CONCLUSIONS: Adenoviral gene transfer of eNOS significantly increased peak and total intracavernous pressure to cavernous nerve stimulation in streptozotocin diabetic rats to a value similar to the response observed in control rats. Our results suggest that eNOS contributes significantly to the physiology of penile erection. These data demonstrate that in vivo adenoviral gene transfer of eNOS can physiologically improve erectile function in the streptozotocin diabetic rat.     

Novel nitric oxide signaling mechanisms regulate the erectile response

Nitric oxide (NO) is a physiologic signal essential to penile erection, and disorders that reduce NO synthesis or release in the erectile tissue are commonly associated with erectile dysfunction. NO synthase (NOS) catalyzes production of NO from L-arginine. While both constitutively expressed neuronal NOS (nNOS) and endothelial NOS (eNOS) isoforms mediate penile erection, nNOS is widely perceived to predominate in this role. Demonstration that blood-flow-dependent generation of NO involves phosphorylative activation of penile eNOS challenges conventional understanding of NO-dependent erectile mechanisms. Regulation of erectile function may not be mediated exclusively by neurally derived NO: Blood-flow-induced fluid shear stress in the penile vasculature stimulates phosphatidyl-inositol 3-kinase to phosphorylate protein kinase B, which in turn phosphorylates eNOS to generate NO. Thus, nNOS may initiate cavernosal tissue relaxation, while activated eNOS may facilitate attainment and maintenance of full erection.     

胰岛素对糖尿病大鼠阴茎内nNOS神经纤维的影响

目的探讨糖尿病性阴茎勃起功能障碍（ED）的发病机制及胰岛素的治疗作用。方法注射链脲佐菌素建立糖尿病（DM）大鼠模型，胰岛素治疗组于成模后注射胰岛素。7周和12周后注射阿扑吗啡（APO）进行大鼠阴茎勃起功能实验，取大鼠阴茎和血浆，用ABC免疫组织化学法观察nNOS神经纤维的变化。测定血浆NOS活性。结果（1）与对照组相比，DM组大鼠阴茎勃起次数明显减少;胰岛素治疗后症状缓解;（2）与对照组相比，DM组血浆NOS活性明显增高;DM组血浆NOS活性与病程延长呈负相关;与DM组比较，胰岛素治疗组血浆NOS活性明显降低;（3）与对照组相比，DM组阴茎内nNOS阳性神经纤维明显减少;与DM组比较，胰岛素治疗组nNOS阳性神经纤维表达增加。结论糖尿病性ED阴茎内nNOS阳性纤维的数量及光密度随DM病程的延长而下降;早期给予胰岛素治疗可预防糖尿病大鼠ED的出现及阴茎内nNOS含量的下降。     

Ameliorative effects of pentoxifylline on NOS induced by diabetes in rat kidney

Objectives Diabetic nephropathy (DN) is the leading cause of end-stage renal disease worldwide. The NO system has been implicated in the pathogenesis of DN. In this study, we aimed to evaluate the healing effect of pentoxifylline on NOS in STZ-induced diabetic rat’s kidney. Material and methods In this study, 50 Wistar albino male rats were used. The rats were divided into five groups; Group C control; Group D only diabetes; Group D?+?PI and D?+?PII diabetes?+?pentoxifylline; Group P only pentoxifylline. Group DPI rats received just pentoxifylline from the beginning of the experiments. However, Group DPII rats received saline in the first month and 50?mg/kg/day of pentoxifylline for the following month. At the end of two months, NOS expressions in kidney tissue were assessed using qRT-PCR and immunohistochemistry analysis. Results At the end of the experiments, desquamation of the epithelial cells of the tubules, clear glycogen-filled distal tubules and increased number of apoptotic cells were seen in Group D. Diabetic rats’ nNOS immunoreactivity had increased and eNOS and iNOS immunoreactivity had decreased; nNOS, iNOS and eNOS mRNA levels tended to decrease compared to the control group. PTX ameliorated eNOS, iNOS and nNOS protein levels and apoptotic cells, but did not affect mRNA levels. Conclusion In conclusion, PTX has a healing effect on this damage by affecting NOS expression.     

Effects of diabetes,insulin and antioxidants on NO synthase abundance and NO interaction with reactive oxygen species

BACKGROUND: Earlier studies have provided evidence for increased production of reactive oxygen species (ROS) and altered nitric oxide (NO) metabolism in diabetes. This study was intended to explore the effect of type I diabetes and its treatment with insulin alone or insulin plus antioxidant-fortified diet on expression of NOS isoforms and ROS interactions with lipids, glucose and NO. METHODS: Rats with streptozotocin-induced diabetes were divided into once-daily insulin (ultralente)-treated, insulin plus antioxidant (vitamin E and vitamin C)-treated and untreated groups. After four weeks, plasma malondialdehyde (MDA) and tissue endothelial (eNOS), neuronal (nNOS) NO synthases, carboxymethyllysine (CML) and nitrotyrosine were determined. RESULTS: The untreated diabetic animals exhibited severe hyperglycemia, elevated blood pressure, increased plasma MDA, high tissue CML and reduced tissue nitrotyrosine denoting enhanced lipid, glucose and protein oxidation but reduced NO oxidation by ROS. This was coupled with significant reduction of eNOS and nNOS expression in renal cortex and eNOS in the left ventricle. Insulin therapy partially lowered blood pressure, tissue CML, plasma glucose and MDA, but significantly raised eNOS expression and nitrotyrosine abundance to supranormal levels. Combined insulin and antioxidant therapies resulted in normalization of blood pressure, plasma MDA, tissue CML and nitrotyrosine without affecting glucose level or NOS expression. CONCLUSION: Oxidative stress in untreated diabetes is associated with down-regulation of NOS isoforms and increased ROS-mediated oxidation of lipid and glucose, but not NO. Amelioration of hyperglycemia with once-daily insulin administration alone results in up-regulation of NOS isoforms, reduction of lipid and glucose oxidation and increased NO oxidation. However, insulin plus antioxidant supplementation can normalize all three parameters.     

Metformin restores the penile expression of nitric oxide synthase in high-fat-fed obese rats

Obesity is a well-known risk factor for erectile dysfunction, which is associated with reduced penile nitric oxide synthase (NOS) expression. Recently it was reported that metformin activates AMP-activated protein kinase (AMPK), which increases the expression of neuronal (n) NOS and endothelial (e) NOS. Thus, to evaluate whether metformin restores NOS expression in penile tissue, we measured penile expression of nNOS and eNOS after 4 weeks of metformin treatment (300 mg/kg/d) in 5-month-old high-fat-fed obese (HFO) rats. HFO rats have increased fat accumulation in visceral areas and marked suppression of nNOS and eNOS expression in penile tissue. However, metformin treatment decreased visceral fat deposition and restored nNOS and eNOS expression in penile tissue. The levels of AMPK and phosphorylated AMPK were also decreased in HFO rats but were subsequently elevated by metformin treatment. These results suggest that expression of NOS was suppressed by the high-fat diet but restored by metformin treatment. The effect of metformin on the expression of NOS may be associated with its activation of AMPK.