衰老对大鼠阴茎组织NO-cGMP通路及端粒酶活性的影响研究

目的探讨衰老对大鼠阴茎组织结构、NO(nitric oxide)-cGMP(cvclic Guanosine Monophosphate)通路及端粒酶活性的影响作用。方法本课题以不同月龄大鼠阴茎组织及培养的平滑肌细胞为研究对象,检测不同月龄大鼠阴茎组织中NO量、NOS(Nitric Oxide Synthase)活性、cGMP量、端粒酶活性及海绵体结构的变化,并比较大鼠、人阴茎组织及大鼠原代海绵体平滑肌细胞的端粒酶活性。结果(1)大鼠阴茎组织中NO量、NOS活性均先升高后降低,各月龄组间有显著差异。阴茎组织cGMP含量逐渐降低,各月龄组间差别显著；(2)随龄增加,平滑肌纤维逐渐减少,胶原纤维增多,粗大成团,窦状隙变少、变窄：(3)大鼠阴茎组织端粒酶活性以2月龄活性最高,随龄增加逐渐下降。人阴茎组织中无端粒酶活性。结论(1)衰老对大鼠阴茎组织结构、NO．cGMP通路及端粒酶活性有显著影响,提示衰老与ED关系密切；(2)大鼠阴茎组织有端粒酶活性,可作为研究细胞衰老与ED关系有关端粒酶的模型。     

淫羊藿苷对兔阴蒂海绵体平滑肌细胞NO及NOS活性的影响

目的 探讨淫羊藿苷对体外培养的兔阴蒂海绵体平滑肌细胞一氧化氮(NO)产生及一氧化氮合酶(NOS)活性的作用效果。 方法 取兔阴蒂海绵体采用酶消化法进行平滑肌细胞体外培养,利用免疫细胞化学染色法通过检测α-actin进行细胞鉴定;利用硝酸还原酶法及NOS试剂盒测定不同浓度淫羊藿苷对阴蒂海绵体平滑肌细胞NO生成及NOS活性的影响。 结果 培养的兔阴蒂海绵体平滑肌细胞呈现典型的平滑肌细胞形态特征;淫羊藿苷浓度依赖性增强家兔阴蒂海绵体平滑肌细胞NOS活性并增加NO生成(P<0.01),且被NOS抑制剂L-硝基精氨酸(LNNA)所抑制(P<0.01)。结论 淫羊藿苷可能通过增强NOS活性而提高阴蒂海绵体平滑肌细胞NO生成,增强性刺激下阴蒂海绵体平滑肌的松弛作用而增强阴蒂胀大勃起功能。     

尼古丁对大鼠阴茎海绵体内源性CO浓度及NOS活性的影响

目的:观察尼古丁对成年雄性大鼠阴茎海绵体内源性一氧化碳(CO)浓度及一氧化氮合酶(NOS)活性的影响,探讨吸烟对勃起功能损害的可能机制。方法:40只成年雄性Wistar大鼠分为4组,尼古丁注射1个月组、2个月组、3个月组和对照组,尼古丁注射组尼古丁0.5 mg/(kg.d)皮下分别注射1、2、3个月,对照组注射生理盐水。处理后,取阴茎海绵体,用改良双波长分光光度法检测CO浓度,改良Griess法检测NOS活性。结果:对照组CO浓度为(13.66±0.40)μmol/mg prot,NOS活性为(9.72±0.47)U/mg prot。尼古丁注射1个月,CO浓度和NOS活性分别下降为(12.43±0.56)μmol/mg prot和(8.44±0.69)U/mg prot,显著低于对照组(P均<0.01);尼古丁注射2个月,CO浓度和NOS活性分别下降为(11.41±0.52)μmol/mg prot和(7.53±0.24)U/mg prot,显著低于对照组和尼古丁注射1个月组(P<0.01);尼古丁注射3个月,海绵体CO浓度和NOS活性分别下降为(10.52±0.59)μmol/mg prot和(6.64±0.31)U/mg prot,均显著低于对照组和尼古丁注射1个月、2个月组(P均<0.01)。结论:尼古丁可导致成年雄性大鼠阴茎海绵体内源性CO浓度及NOS活性下降,提示内源性CO及NOS参与吸烟引起勃起功能障碍的病理生理过程。     

睾酮对体外大鼠阴茎海绵体组织细胞增殖的影响

目的:探讨睾酮对雄性SD大鼠阴茎海绵体组织细胞增殖的影响。方法:无菌条件下获取大鼠阴茎海绵体组织,免疫组化法检测其雄激素受体的表达,再分别采用酶消化法培养平滑肌细胞和贴壁法培养成纤维细胞,用四氮唑蓝(MTT)还原法观察对照组及睾酮10-8mol/L、10-7mol/L、10-6mol/L、10-5mol/L、10-4mol/L、10-3mol/L浓度组对海绵体组织细胞增殖的影响。结果:雄激素受体在大鼠阴茎海绵体组织表达,10-5mol/L睾酮刺激可促进大鼠阴茎海绵体平滑肌细胞和成纤维细胞增殖,MTT还原法测定分别为68100±2200和70200±1300(P<0.05);10-4mol/L睾酮刺激可抑制平滑肌细胞和成纤维细胞增殖,MTT法测定A值为分别55000±1400和59100±1500(P<0.01);其他组作用不显著。结论:大鼠阴茎海绵体组织存在雄激素受体,睾酮可经雄激素受体途径对阴茎海绵体组织细胞增殖的产生影响,不同浓度睾酮可促进或抑制海绵体平滑肌细胞和成纤维细胞的增殖。     

人参皂甙对去势大鼠阴茎海绵体组织NO含量与细胞凋亡的影响

目的研究人参皂甙对去势大鼠阴茎海绵体组织细胞凋亡、NO含量的影响,探讨人参皂甙壮阳功效的可能机制。方法40只成年雄性大鼠随机分为去势组、对照组及不同剂量(25mg/kg、100mg/kg)人参皂甙组共4组,1周后取阴茎海绵体,放免法检测血清睾酮含量(ng/ml),全自动生化分析仪比色法测定海绵体NO含量(μg/g),末端脱氧核糖核酸转移酶介导的duTP缺口末端标记法测定细胞凋亡。结果对照组血清睾酮水平浓度为(1.51±0.86),在去势组、人参皂甙治疗组(25mg/kg、100/mg/kg)均未测到。去势组阴茎海绵体NO浓度(14.45±2.38)较对照组(39.8±3.28)显著降低(P<0.01),25mg/kg人参皂甙组阴茎海绵体NO水平(16.02±2.67)与去势组(14.45±2.38)接近(P>0.05),100mg/kg人参皂甙组NO水平(37.88±7.06)较去势组细胞凋亡数(14.45±2.38)明显升高(P<0.05),与对照组(39.8±3.28)接近(P>0.05)。大剂量100mg/kg人参皂甙组(12.51±1.81)较去势组(26.02±5.25)低(P<0.05)。25mg/kg人参皂甙组凋亡细胞积分光密度(27269.60±4920.42)与去势组比较(33931.50±2459.36)差异无统计学意义,大剂量100mg/kg人参皂甙组(18766.36±3040.42)较去势组(33931.54±2459.36)低,两者比较差异有统计学意义(P<0.05)。结论100mg/kg剂量的人参皂甙不能增加去势大鼠血清睾酮含量,但可以提高去势大鼠阴茎海绵体组织NO水平,减少海绵体细胞凋亡。人参皂甙对去势大鼠阴茎海绵体细胞凋亡的抑制作用可能与其增加NO水平有关。     

IGF-1基因治疗提高老龄大鼠阴茎海绵体平滑肌密度的研究

目的 观察阴茎海绵体内注射胰岛素样生长因子-1 (IGF-1)基因能否提高老年性大鼠阴茎勃起功能及其对阴茎海绵体平滑肌密度的影响,以探讨IGF-1基因治疗ED的机制.方法 4月龄SD雄性大鼠(青年组)10只;24月龄SD雄性大鼠(老龄组)20只,随机分为2组:PBS对照组、100 μg IGF-1质粒注射组.每组10只注射后8周行电刺激检测大鼠阴茎海绵体内压(ICP)和平均动脉压(MAP),分析比较IGF-1基因治疗的效果,Masson,s三色染色图文定量分析阴茎海绵体平滑肌在海绵体组织中含量的变化.结果 电刺激发现老龄组较青年组ICP/MAP和总ICP明显降低(P＜0.05).IGF-1基因治疗8周后,100 μg IGF-1质粒注射组较PBS对照组ICP/MAP和total ICP均明显提高(P＜0.05);阴茎海绵体平滑肌的含量在老龄组较青年组明显降低(P＜ 0.05);与PBS对照组比较,100μg IGF-1质粒注射组能够明显提高阴茎海绵体平滑肌的含量(P＜0.05).结论 I GF-1基因治疗能够改善老龄大鼠的勃起功能,其作用机制之一可能是通过提高阴茎海绵体平滑肌的含量.     

慢性肾功能衰竭性勃起功能障碍大鼠阴茎海绵体有效成分的测定

目的:探讨慢性肾功能衰竭(CRF)性勃起功能障碍(ED)的发病机制。方法:应用SD雄性大鼠分两期行5/6肾脏切除术,建立CRF动物模型。将假手术组(NCRF组,n=30)、CRF模型大鼠(CRF组,n=45)分别随机均分为Ⅰ(2周)、Ⅱ(4周)、Ⅲ(6周)3组,并分别于2、4、6周注射阿朴吗啡(APO,80μg/kg)后观察大鼠阴茎勃起情况,筛选CRF性ED模型大鼠;测定阴茎海绵体组织一氧化氮合酶(NOS)的活性,及其组织的M asson染色图像分析。结果:CRF性ED大鼠阴茎海绵体组织NOS活性及平滑肌面积显著降低(P<0.01或P<0.05),胶原纤维略有增加,且上述变化与CRF病程密切相关。海绵窦血管腔无明显变化。结论:CRF严重影响阴茎勃起功能,阴茎海绵体组织NOS活性降低及阴茎海绵体平滑肌面积的减少可能是其重要的发病机制。     

不同剂量香烟烟雾提取物对阴茎海绵体NOS活性和Cx43蛋白的影响

目的:探讨不同剂量的香烟烟雾提取物对雄性大鼠勃起功能的影响,进一步研究吸烟导致ED的发病机制。方法:75只健康雄性SD大鼠(8周龄),随机分为5组(15只/组)。A组为对照组;B组为皮下注射二甲基亚砜(DMSO)组;C组为皮下注射香烟烟雾提取物(CSE)低剂量组;D组为皮下注射CSE中剂量组;E组为皮下注射CSE高剂量组。应用SD雄性大鼠建立皮下注射CSE模型60 d后,经皮下注射阿朴吗啡(APO)后观察大鼠阴茎勃起情况,处死大鼠取阴茎海绵体组织。一部分标本采用激光共聚焦扫描显微镜方法检测缝隙连接蛋白43(Cx43)的表达;另一部分标本采用比色法测定大鼠阴茎海绵体组织中NOS活性。结果:不同剂量CSE组阴茎勃起次数、阴茎海绵体组织NOS活性和海绵体平滑肌中Cx43表达与DMSO组和对照组比较均明显减少(P<0.05)。实验组中,阴茎勃起次数、阴茎海绵体组织NOS活性和Cx43表达均随着CSE剂量的增加而减少。DMSO组与对照组比较差异无统计学意义(P>0.05)。结论:CSE使阴茎海绵体组织NOS活性明显降低、海绵体平滑肌中Cx43蛋白表达明显减少并且严重影响阴茎勃起功能,并且CSE剂量越大,其影响越明显。提示,Cx43蛋白表达下调、NOS活性降低可能是CSE导致ED的发病机制之一。     

甲状腺素对大鼠阴茎海绵体内NOS及CO含量影响的研究

目的:建立甲状腺功能亢进及甲状腺功能减退Wistar大鼠动物模型,检测其阴茎海绵体内NOS及内源性一氧化碳(CO)的含量,探讨甲状腺素对大鼠勃起功能的影响及内源性CO在阴茎海绵体勃起过程中的作用,进一步讨论甲状腺素对人类勃起功能的影响。方法:将50只3月龄雄性Wistar大鼠随机均分为甲亢组、甲亢治疗组、甲减组、甲减治疗组及正常对照组。用紫外分光光度计分别测定阴茎海绵体内NOS及CO的含量。结果:无论甲状腺素增多及减少都会使大鼠阴茎海绵体NOS含量降低(P<0.01),并且甲减组阴茎海绵体内NOS活性低于甲亢组(P<0.01)。无论甲状腺素增多还是减少都会使大鼠阴茎海绵体内CO含量降低(P<0.01),并且甲亢组阴茎海绵体内CO活性低于甲减组(P<0.01)。在对甲减组及甲亢组进行治疗后其CO及NOS的含量得到提高,与正常对照组无显著差异(P>0.05)。结论:甲状腺功能紊乱情况下阴茎海绵体中NOS和CO的浓度均减低;甲状腺功能紊乱被及时纠正后阴茎海绵体中CO及NOS的含量可恢复到正常水平。在相同条件下甲状腺功能低下对性功能的损害强于甲状腺功能亢进对勃起功能的损害。     

增龄对雄性大鼠阴茎海绵体平滑肌中P47~(phox)表达的影响

目的 探讨增龄对雄性SD大鼠阴茎海绵体平滑肌中P47~(phox)表达的影响.方法 4月、8月和12月龄3组SD大鼠各20只,取阴茎海绵体平滑肌,应用Real-time RT-PCR和Western印迹法检测各组阴茎海绵体平滑肌组织中P47~(phox)的基因和蛋白表达的变化.结果 荧光定量RT-PCR显示P47~(phox) mRNA的表达随年龄增长逐渐增高,8月龄大鼠阴茎海绵体平滑肌P47~(phox) mRNA的表达是4月龄大鼠的1.28倍,12月龄大鼠阴茎海绵体平滑肌P47~(phox) mRNA的表达是4月龄大鼠的8.57倍.Western印迹法显示,P47~(phox)蛋白在大鼠阴茎海绵体平滑肌组织中的表达随年龄增长逐渐增高.结论 随着月龄的增加,P47~(phox) mRNA和蛋白质水平在大鼠阴茎海绵体平滑肌中逐渐增高,P47~(phox)可能在增龄诱导阴茎勃起功能障碍过程中发挥重要作用.     

Endogenously formed nitric oxide modulates cell growth in bladder cancer cell lines

Objectives. Nitric oxide (NO) is formed in many mammalian tissues, and a growing body of evidence suggests that NO is involved in cell growth and cell differentiation. Low concentrations of NO can stimulate cell growth; high concentrations result in cytostatic/cytotoxic effects. It has previously been shown that intravesical treatment with bacille Calmette-Guérin (BCG) for bladder cancer increases NO production in the human urinary bladder and that NO inhibits bladder cancer cell growth in vitro. In this study, we investigated nitric oxide synthase (NOS) activity in different bladder cancer cells and the role of the NO precursor -arginine in cell proliferation.Methods. NOS activity was assessed by citrulline assay in cultured normal human urothelial cells and bladder cancer cell lines T24 and MBT-2 before and after treatment with cytokines. We also measured cell growth at various -arginine concentrations and after addition of the NOS inhibitor N^G-nitro- -arginine ( -NNA) in unstimulated and cytokine-stimulated cells.Results. Normal urothelial cells, as well as T24 and MBT-2 cells, showed calcium-dependent NOS activity under basal conditions. The bladder cancer cell lines also showed calcium-independent NOS activity in contrast to the normal cells. After cytokine treatment, both the normal cells and the cancer cell lines showed a marked increase in calcium-independent NOS activity. There was a dose-dependent stimulation of cell growth in the cancer cell lines after -arginine addition, and this effect could be antagonized by -NNA. Cytokine treatment inhibited cell growth, and this inhibition was partly reversed by -NNA.Conclusions. Normal urothelial cells and bladder cancer cell lines MBT-2 and T24 show NOS activity, and cytokine treatment induces calcium-independent NOS activity. Our results suggest that endogenous activity of the constitutively expressed form of NOS in unstimulated cells promotes cell proliferation, and NO production secondary to increased activity of the inducible form of NOS after cytokine treatment inhibits cell growth.     

Involvement of increased arginase activity in impaired cavernous relaxation with aging in the rabbit

PURPOSE: Arginase shares L-arginine as a common substrate with nitric oxide (NO) synthase (NOS). We examined whether increased arginase activity is involved in impaired cavernous relaxation with aging in the rabbit. MATERIALS AND METHODS: Young adult (3 to 5 months old) and aged (36 to 48 months old) rabbits were used for the current experiments. Cavernous tissues obtained from the 2 groups were processed for isometric tension experiments, cyclic guanosine monophosphate determination, measurements of NOS and arginase activities, endogenous methylarginines and L-arginine. RESULTS: Carbachol (CCh) produced an endothelium dependent and NO mediated relaxation that was significantly impaired in aged cavernous specimens without change in sodium nitroprusside induced relaxation. Stimulated cyclic guanosine monophosphate production with CCh was significantly decreased in aged cavernous specimens. Ca dependent NOS was predominant in rabbit cavernous specimens. Ca dependent and independent NOS activities remained unchanged in the 2 groups. The tissue contents of N-monomethyl-L-arginine and asymmetric N,N-dimethyl-L-arginine as endogenous NOS inhibitors, symmetrical N,N'-dimethyl-L-arginine and L-arginine as a substrate of NOS were decreased in aged cavernous specimens. Arginase activity was significantly higher in aged cavernous specimens. Impaired CCh induced relaxation in aged cavernous specimens was normalized in the presence of N-hydroxy-L-arginine as an arginase inhibitor or by the supplementation of excess L-arginine. CONCLUSIONS: These results strongly suggest that impaired endothelium dependent and NO mediated cavernous relaxation with aging is due to decreased NO production, which would result from increased arginase activity and probably from decreased L-arginine content.     

Sexual dimorphism in the aging kidney: Effects on injury and nitric oxide system

BACKGROUND: Male gender confers enhanced susceptibility to development of age-dependent kidney damage. In other models of progressive renal disease, development of injury is linked to declines in renal nitric oxide synthase (NOS) capacity. METHODS: We investigated the in vitro characteristics of the renal NOS system in young (3 to 5 months), middle-aged (11 to 13 months) and old (18 to 22 months) male and female Sprague-Dawley rats. RESULTS: NOS activity (pmol [3H]-arginine converted to [3H]-citrulline/mg protein/minute) is reduced in the soluble fraction of renal cortex from old versus young males but not females. In contrast, NOS activity in the soluble fraction of cerebellum is not altered by age or gender. The abundance of endothelial NOS (eNOS) and neuronal (nNOS) is reduced in renal cortex of old versus young males but is unchanged in female cortex. In renal medulla, eNOS protein is reduced with age in both males and females. We found no difference in abundance of either eNOS or nNOS protein in the cortex of young male and female rats. The incidence and severity of glomerular damage increases markedly with age in the male and only slightly in the female. CONCLUSION: These findings indicate that a relative reduction occurs in renal NOS in the male kidney with advancing age, whereas NOS protein and activity is maintained during aging in females. This, together with the marked age-dependent kidney damage seen in the male, suggests that the renal NO deficiency in the aging male rat may contribute to the age-dependent kidney damage.     

Mechanical strain stimulates nitric oxide production by rapid activation of endothelial nitric oxide synthase in osteocytes.

Previous studies have indicated that physiological levels of dynamic mechanical strain produce rapid increases in nitric oxide (NO) release from rat ulna explants and primary cultures of osteoblast-like cells and embryonic chick osteocytes derived from long bones. To establish the mechanism by which loading-induced NO production may be regulated, we have examined: nitric oxide synthase (NOS) isoform mRNA and protein expression, the effect of mechanical loading in vivo on NOS mRNA expression, and the effect of mechanical strain on NO production by bone cells in culture. Using Northern blot analyses, in situ hybridization, and immunocytochemistry we have established that the predominant NOS isoform expressed in rat long bone periosteal osteoblasts and in a distinct population of cortical bone osteocytes is the endothelial form of NOS (eNOS), with little or no expression of the inducible NOS or neuronal NOS isoforms. In contrast, in non-load-bearing calvariae there are no detectable levels of eNOS in osteocytes and little in osteoblasts. Consistent with these observations, ulnar explants release NO rapidly in response to loading in vitro, presumably through the activation of eNOS, whereas calvarial explants do not. The relative contribution of different bone cells to these rapid increases in strain-induced NO release was established by assessment of medium nitrite (stable NO metabolite) concentration, which showed that purified populations of osteocytes produce significantly greater quantities of NO per cell in response to mechanical strain than osteoblast-like cells derived from the same bones. Using Northern blot hybridization, we have also shown that neither a single nor five consecutive daily periods of in vivo mechanical loading produced any significant effect on different NOS isoform mRNA expression in rat ulnae. In conclusion, our results indicate that eNOS is the prevailing isoform expressed by cells of the osteoblast/osteocyte lineage and that strain produces increases in the activity of eNOS without apparently altering the levels of eNOS mRNA.     

Renal cortical nitric oxide synthase activity during maturational growth in the rat

The present study was designed to test the hypothesis that growth from puberty to adulthood in the rat is associated with an increase in renal cortical nitric oxide synthase (NOS) activity that results in an augmented impact of nitric oxide (NO) on hemodynamic function. Two groups of male Sprague-Dawley rats were studied: juvenile rats (approximately 2 months old) and mature rats (approximately 5 months old). NOS activity, measured as -nitro-L-arginine (NNA)-sensitive (3)H-L-citrulline production from (3)H-L-arginine, was significantly higher in the renal cortex of mature rats (57+/-2 pmol/h per mg protein) than in juveniles (42+/-3 pmol/h per mg protein). Additional animals from each group were anesthetized to determine the acute impact of NOS inhibition on arterial pressure and renal cortical blood flow, measured by single-fiber Doppler flowmetry. Cortical blood flow was higher in mature rats than in juveniles, averaging 22+/-2 and 16+/-1 perfusion units, respectively. NOS inhibition (10 mg/kg NNA i.v.) decreased renal cortical blood flow in mature rats by 35+/-7%, but only by 9+/-4% in juvenile animals. These data support the hypothesis that maturational growth in the rat is associated with augmented NOS activity coupled with an increased tonic influence of NO on renal cortical blood flow.     

The effects of static and intermittent compression on nitric oxide production in articular cartilage explants.

Nitric oxide (NO) production and NO synthase (NOS) expression are increased in osteoarthritis and rheumatoid arthritis, suggesting that NO may play a role in the destruction of articular cartilage. To test the hypothesis that mechanical stress may increase NO production by chondrocytes, we measured the effects of physiological levels of static and intermittent compression on NOS activity, NO production, and NOS antigen expression by porcine articular cartilage explants. Static compression significantly increased NO production at 0.1 MPa stress for 24 h (P < 0.05). Intermittent compression at 0.5 Hz for 6 h followed by 18 h recovery also increased NO production and NOS activity at 1.0 MPa stress (P < 0.05). Intermittent compression at 0.5 Hz for 24 h at a magnitude of 0.1 or 0.5 MPa caused an increase in NO production and NOS activity (P < 0.05). Immunoblot analysis showed stress-induced upregulation of NOS2, but not NOS1 or NOS3. There was no loss in cell viability following any of the loading regimens. Addition of 2 mM 1400 W (a specific NOS2 inhibitor) reduced NO production by 51% with no loss of cell viability. These findings indicate that NO production by chondrocytes is influenced by mechanical compression in vitro and suggest that biomechanical factors may in part regulate NO production in vivo.     

大鼠阴茎组织中NOS表达及增龄的影响

为探讨大鼠阴茎组织中一氧化氮合酶分布及增龄对其的影响。本文采用ＮＡＤＰＨｄ组化对不同月龄大鼠阴茎组织进行染色。结果显示ＮＯＳ主要分布于大鼠阴茎组织平滑肌细胞,而内皮和社会纤维含量较少;随年龄增加,阴茎组织中ＮＯＳ表达逐渐减弱,各月龄组间差别明显。     

衰老对大鼠阴茎海绵体NOS I的表达和NOS活性的影响

目的 :探讨衰老对大鼠阴茎海绵体一氧化氮合酶Ⅰ (NOSⅠ)mRNA、蛋白的表达和NOS活性的影响。　方法 :30只雄性SD大鼠按不同月龄分为成年组、老年组和衰老组 ,应用Western印迹、RT PCR方法分别检测不同年龄组阴茎海绵体NOSⅠ蛋白及mRNA的表达 ;用紫外分光光度计测定不同年龄组阴茎海绵体NOS的活性。　结果 :成年组NOSⅠ 蛋白的表达量最高 ,老年组和衰老组显著降低 ,分别为成年组的 75 .6 %和 6 1.2 % ;NOSⅠmRNA的表达与蛋白表达的变化一致 ;老年组NOS活性与成年组差异无显著性 (P >0 .0 5 ) ,衰老组NOS活性明显降低 ,是成年组的70 .4 % ,并且差异非常显著 (P <0 .0 1)。　结论 :衰老引起NOSⅠ 蛋白及mRNA的表达降低和NOS活性的显著降低 ,可能是老年性阴茎勃起功能障碍的主要机制之一。