An evaluation of semen characteristics in men 45 years of age or older after daily dosing with tadalafil 20mg: results of a multicenter, randomized, double-blind, placebo-controlled, 9-month study

OBJECTIVES: Assess the effects on spermatogenesis of daily tadalafil 20mg over three spermatogenesis cycles in men >or= 45 yr. METHODS: In this double-blind, placebo-controlled, noninferiority study, healthy men (or with mild erectile dysfunction) were randomized to receive tadalafil 20mg (n=125) or placebo (n=128) for 9 mo followed by a 6-mo, treatment-free period. Semen and serum samples were provided at baseline and every 10-12 wk. The primary outcome was the proportion of subjects with >or= 50% reduction in sperm concentration at end point. Secondary outcomes included sperm concentration, number per ejaculate, motility and morphology; serum concentrations of testosterone, luteinizing and follicle-stimulating hormones; and tolerability. RESULTS: Of 253 men enrolled, 191 (75%) completed treatment phase: 2 of 96 (2.1%, placebo) and 12 of 95 (12.6%, tadalafil) subjects had >or= 50% reduction in sperm concentration. Tadalafil was noninferior to placebo because the upper 95% confidence interval for the difference in proportions of tadalafil and placebo subjects with a >or= 50% reduction in sperm concentration was 17.5%, significantly less than the prespecified noninferiority margin of 20% (p=0.015). Ninety-four percent (179 of 191) of men completed the 6-mo, treatment-free period: Baseline sperm concentration levels were restored in 8 of 12 (tadalafil) and 1 of 2 (placebo) men. There were no significant differences between groups in secondary end points. Common treatment-emergent adverse events were headache, back pain, dyspepsia, gastroesophageal reflux disease, and myalgia. Twelve (9.6%) tadalafil and seven (5.5%) placebo subjects discontinued because of adverse events. CONCLUSIONS: This study demonstrated no deleterious effects of 9 mo of daily tadalafil 20mg on spermatogenesis or hormones related to testicular function in men >or= 45 yr.     

Actin binding proteins,actin cytoskeleton and spermatogenesis – Lesson from toxicant models

Actin cytoskeleton is crucial to support spermatogenesis in the mammalian testis. However, the molecular mechanism(s) underlying changes of actin cytoskeletal organization in response to cellular events that take place across the seminiferous epithelium (e.g., self-renewal of spermatogonial stem cells, germ cell differentiation, meosis, spermiogenesis, spermiation) at specific stages of the epithelial cycle of spermatogenesis remain largely unexplored. This, at least in part, is due to the lack of suitable study models to identify the crucial regulatory proteins and to investigate how these proteins work in concert to support actin dynamics. Much of the information on the role of actin binding proteins in the literature, namely the actin bundling proteins, actin nucleation proteins and motor proteins, are either findings based on genetic models or morphological analyses. While this information is helpful to delineate the function of these proteins to support spermatogenesis, they are not helpful to identify the regulatory signaling proteins, the signaling pathways and the cascade of events to modulate actin cytoskeleton dynamics. Recent studies based on the use of toxicant models, both in vitro and in vivo, however, have bridged this gap by identifying putative regulatory and signaling proteins of actin cytoskeleton. Herein, we summarize and critically evaluate these findings. We also provide a hypothetical model by which actin cytoskeletal dynamics in Sertoli cells are regulated, which in turn supports spermatid transport across the seminiferous epithelium, and at the blood-testis barrier (BTB) during the epithelial cycle of spermatogenesis.     

胱蛋白酶抑制剂相关的附睾精子发生基因的调节和功能

CRES(cystatin relatedepididymalspermatogenic,胱蛋白酶抑制剂相关的附睾精子发生 )蛋白是胱蛋白酶抑制剂(cystatin)超家族中家族 2的一个亚类。然而 ,与cystatinC的广泛性表达不同 ,Cres基因只在分裂后的生殖细胞、附睾头部近端和腺垂体促性腺激素细胞中表达。cystatin对C1半胱氨酸蛋白酶抑制作用的发挥必须有 3个共有位点的参与 ,而CRES蛋白缺少其中的 2个位点。因此 ,CERS在生殖系统和神经内分泌系统中的功能也许是独特的和组织特异性的。本文概述了以下方面的研究 :①Cres基因启动子及其转录调节蛋白相关的可能对Cres的组织特异性表达有重要作用的DNA结合位点。②CRES蛋白的生物学功能。Norethern印迹法、凝胶转移分析和瞬时转染实验均表明 ,附睾和促性腺激素细胞中主要表达C EBP家族中的C EBPβ(CCAAT 增强子结合蛋白 ) ,且C EBPβ对于Cres基因在这两个组织中的高表达是必不可少的。另外 ,构建了表达氯霉素乙酰基转移酶 (CAT)报告基因的转基因小鼠 ,CAT报告基因由Cres基因 5′端 1 6kb的启动子所调控。分析显示 ,CATmRNA仅在生殖细胞中表达 ,说明Cres 5′端 1 6kb的侧翼区含有调控CAT在睾丸中表达的DNA序列 ,而缺乏指导CAT在附睾中表达的序列 ,或者此1 6kb的DNA片段存在Cres的负调节成分。最后 ,     

辐射对小鼠精子发生过程中印记基因表达的影响

目的筛选在小鼠精子发生过程中受电离辐射影响表达发生改变的印记基因。方法选择雄性BALB／c小鼠8只，分为实验组和对照组X射线全身照射0．1Gy／d，连续13d，建立辐射干扰小鼠精子发生模型。提取实验组和对照组睾丸RNA，采用上海生物芯片中心小鼠寡核苷酸基因表达谱芯片筛选表达发生改变的印记基因，对感兴趣的基因经半定量RT—PCR验证。结果12个表达发生改变的印记基因，6个上调，6个下调，其中Igf2、Peg3基因Ratio值分别为3．859和0．397，经半定量RT—PCR验证与芯片结果相符。结论X射线全身照射可导致小鼠睾丸部分印记基因表达发生改变。     

人类趋化素样因子超家族2在精索静脉曲张大鼠模型中的表达

目的：通过建立精索静脉曲张大鼠模型,探讨人类趋化素样因子超家族2（chemokine like factor-like myelin and lymphocyte and related proteins for vesicle trafficking and membrane link transmembrane domain-containing protein 2, CMTM2）对精索静脉曲张大鼠生精过程的影响。方法：选取雄性SD大鼠40只（体重220~330 g,6~7周龄）,将大鼠随机分为精索静脉曲张持续4、12周后处死取样组,和相应的接受假手术处理的对照组,每组均为10只大鼠。通过手术进行左肾静脉缩窄建立左侧精索静脉曲张的大鼠模型。将实验组和对照组大鼠于4周或12周后处死,取出左侧睾丸,游离附睾中精子,观察并计算精子密度与活力,测量生精小管外径、内径及上皮直径改变,并进行免疫组织化学分析以判断CMTM2蛋白的表达状况。结果：与对照组相比,精索静脉曲张4周组中大鼠的精子密度［（63.9±7.1）×106/mL vs.（74.3±5.0）×106/mL］和活力［（58.7%±7.9%） vs. （66.1%±4.3%）］ 轻度下降（t=1.432, 1.563; P=0.076, 0.059）,精索静脉曲张12周组中大鼠的精子密度［（40.5±7.2）×106/mL vs.（71.1±4.5）×106/mL］和活力［（35.2%±8.5%） vs. (63.4%±4.1%)］显著下降（t=3.754, 3.933; P=0.004, 0.002）。此外,CMTM2蛋白的表达水平在精索静脉曲张组也出现明显下降,对照组CMTM2水平为精索静脉曲张12周组的（2.3±0.4）倍（t=1.978; P=0.039）。4周时,精索静脉曲张组生精小管外径出现轻度降低［（271.1±8.4）μm vs. （280.0±8.1）μm,t=1.361, P =0.132］,而12周组则出现明显降低［（198.2±10.2） μm vs. （255.8±12.7）μm,t=2.125, P=0.003］,此外,精索静脉曲张12周组的生精小管上皮直径出现明显下降［（54.1±1.5）μm vs.（75.5±4.1）μm,t=2.246,P=0.021］。结论：在精索静脉曲张大鼠模型中,精索静脉曲张与CMTM2蛋白水平降低相关,同时可导致睾丸生精小管直径变小及精子密度与质量受损。     

Studies on the sexual behaviour, haematology and spermatogenesis of male rabbits infected with Trypanosoma brucei brucei

A total of 24 crossbreed buck rabbits (New Zealand White × chinchilla) were used to evaluate the effect of experimental infection with Trypanosoma brucei on symptoms, sexual behaviours, haematology and spermatogenesis. The rabbits were divided into two groups (A and B) of 12 rabbits each. Group A rabbits were infected with 1.25 × 10⁶ of T. brucei, whereas group B served as the uninfected control. The trypanosomes were detectable in the blood of all the infected bucks by day 7 post-infection (PI) with mean pre-patent period of 4.7 ± 0.85 days. The red blood cell (RBC) and packed cell volume (PCV) decreased significantly (P < 0.05) from day 8 to 28 PI. The values however improved from day 36 PI and were similar to the uninfected control. The reverse was the case of parasitaemia. Two rats died at the peak of the decrease in RBC and PCV and increase in parasitaemia. There was also significant (P < 0.05) loss in live and testis weights, reduced libido and impaired spermatogenesis in the infected group. The infected bucks showed clinical signs similar to that reported in other trypanosome-infected animals. It is concluded that susceptibility of crossbreed rabbits usually kept in Africa to pathogenic trypanosomes is characterised by an acute stage manifested by anaemia, high parasitaemia and death and chronic stage manifested by improved PCV and RBC, very low parasitaemia but high tissue damage and low productivity. Control of this disease in endemic areas for purpose of commercial rabbit production is advocated.     

DAZ及DAZH基因与精子发生的相关性分析

ＤＡＺ基因（ｄｅｌｅｔｅｄｉｎａｚｏｏｓｐｅｒｍｉａ）是无精子因子（ＡＺＦ）的重要候选成分，它的缺失可致无精子或严重少精子症。人第３号染色体上存在着ＤＡＺ的同源基因ＤＡＺＨ（ＤＡＺｈｏｍｏｌｏｇｕｅ），为探讨ＤＡＺ和ＤＡＺＨ基因在精子发生中的作用，我们用聚合酶链反应（ＰＣＲ）方法检测了６６名正常生育男性和９０例原发性不育男性基因组ＤＮＡ的ＤＡＺ、ＤＡＺＨ基因。结果：原发性不育男性中１２例ＤＡＺ缺失（无精子症８例，严重少精子症４例）；正常男性ＤＡＺ无一缺失；在正常男性和不育男性中均有ＤＡＺＨ缺失。结果进一步证实ＤＡＺ为ＡＺＦ的候选成分，而ＤＡＺＨ基因与精子发生似无直接的相关性。     

COMMENTS

Glial-cell-line-derived neurotrophic factor (GDNF) is a distant member of the transforming growth factor superfamily. It binds to and activates a receptor complex consisting of GFR-α1 and Ret receptor tyrosine kinase. In testis, GDNF is expressed by Sertoli cells. We have shown by transgenic loss- and gain-of-function mouse models that GDNF regulates the cell fate decision of undifferentiated spermatogonia. In the GDNF +/− mice, the spermatogonia differentiate in excess leading to the depletion of germ cells. In the mice overexpressing GDNF in testes, undifferentiated spermatogonia accumulate in the tubules, no sperm is produced, and the mice are infertile. After a year, the GDNF overexpressing mice frequently (89%) develop testicular tumours, and most of them are bilateral (56%). All these tumours show the same histological pattern. They are composed of round spermatogonial/gonocytic cells with only a scant cytoplasm. The tumours are locally invasive but do not metastasise. They express germ line markers, are positive for alkaline phosphatase, and aneuploid with a triploid peak. Thus, by several histological, molecular, and histochemical characteristics, the GDNF-induced tumours mimic classical seminomas in men, but the precursor lesions are apparently different in mouse and man.     

小鼠去胸腺后睾丸内生精细胞的变化

本文通过对成熟期与未成熟期的小鼠施行胸腺切除术,并于术后35天应用图像分析仪对睾丸生精上皮内的各级生精细胞进行了定量分析.结果显示,生精上皮内各级生精细胞均明显减少,表明在精子发生过程中胸腺及其所分泌的激素不仅对减数分裂有刺激作用,而且对有丝分裂也有刺激作用,提示胸腺睾丸轴在精子发生过程中起重要作用.