Spatiotemporal expression patterns of natriuretic peptides in rat testis and epididymis during postnatal development

Natriuretic peptide (NP) family is composed of atrial, brain and C‐type NP (NPPA, NPPB and NPPC). Here, we aimed to investigate NP expression in testis and epididymis during postnatal development. NPPA expression was observed in gonocytes at prepubertal period but in only spermatocytes in pachytene and leptotene/zygotene stage at pubertal period. In prepubertal and pubertal periods, we detected NPPB expression in only Leydig cells. However, NPPC expression was detected in all of the gonocytes and Sertoli cells, spermatocytes and some interstitial cells in prepubertal and pubertal periods. In postpubertal and mature periods, NPPA and NPPB staining were detected in Leydig cells, elongated and round spermatids but not in spermatogonia and spermatocytes. However, we observed NPPC expression in all cells of the seminiferous tubules and Leydig cells in the postpubertal and mature periods. Epididymal epithelium showed intense NPPC expression during postnatal period but weak NPPA and NPPB expression in prepubertal and pubertal periods. The expression of three NPs in the testis significantly increased after puberty. In conclusion, puberty had a significant effect on NP expression in testis. Unlike NPPA and NPPB, expression of NPPC in all cells of the seminiferous tubule suggests that NPPC is effective in each step of spermatogenesis.     

Expression and localization of N- and E-cadherin in the human testis and epididymis

Cellular interactions in the testis and epididymis are an important prerequisite for spermatogenesis and sperm maturation, and involve a well-developed complex of intercellular junctions. Cadherins are cell surface proteins which mediate intercellular Ca2+ -dependent adhesion and are believed to be fundamentally important for maintaining multicellular structures. In the present study we report the expression of a 135 kDa N-cadherin polypeptide in the human seminiferous epithelium by immunoblotting. The presence of N-cadherin was demonstrated by immunohistochemistry on the surface of spermatogonia and primary spermatocytes, and possibly also around some early spermatids, whereas late spermatids were always negative. Endothelial cells also stained for N-cadherin, whereas peritubular cells and Leydig cells did not. No expression of E-cadherin could be demonstrated in the human testis. In the human epididymis E-cadherin, but not N-cadherin, was expressed and localized to the surface of the principal epithelial cells as shown by immunohistochemistry. These observations indicate that cadherins play an important role in the organization of the seminiferous and epididymal epithelium.     

二甲磺酸乙烷致间质细胞破坏所引起的成年大鼠睾丸和附睾的组织学变化:形态定量研究

目的:定量研究睾酮分泌剧烈减少所致睾丸和附睾的组织学变化。方法:14只成年 SD 大鼠腹腔内注射二甲磺酸乙烷(EDS,75mg/kg),14只注射生理盐水作为对照。7天后处死各组中的一半动物,过5天后处死另一半。取睾丸和附睾组织块,甲基丙烯酸树脂包埋。用体视学的光学体视框技术估计睾丸内的细胞数,并用其它形态定量研究方法获取另外一些参数。结果:EDS 注射使睾丸内的间质细胞几乎完全消失,但对支持细胞总数没有影响。EDS 注射7天后,生精上皮内可见许多长形精子细胞滞留,附睾管内可见许多圆形精子细胞。EDS 注射12天后,精子细胞和精母细胞的排列明显变疏松,生精细胞之间出现明显的裂隙,裂隙近似放射状朝向生精小管腔;睾丸内的非 B 型精原细胞总数和精母细胞总数与对照组相似,但 B 型精原细胞总数增加59%,而早期(圆形)、中期和晚期(长形)精子细胞总数分别减少37%、72%和52%。结论:EDS 所致精子发生损害主要是(1)精子释放障碍,(2)精子细胞、精母细胞分离并伴有精子形成和成熟分裂障碍。     

Histological changes of the testis and epididymis in adult rats as a result of Leydig cell destruction after ethane dimethane sulfonate treatment： a morphometric study

Aim： To quantitatively study the histological changes of the testis and epididymis as a result of a drastic reduction of testosterone secretion. Methods： Fourteen adult Sprague-Dawley rats were injected intraperitoneally with ethane dimethane sulfonate （EDS, 75 mg/kg） and the same number of animals were injected with normal saline as a control. At days 7 and 12 （after treatment）, respectively, half of the animals from each group were killed. The testes and epididymides were removed and tissue blocks embedded in methacrylate resin. The cell number per testis was estimated using the stereological optical disector and some other parameters were obtained using other morphometric methods. Results： The EDS treatment resulted in an almost complete elimination of Leydig cells but had no effect on the numbers of Sertoli cells per testis. At day 7 after EDS treatment, many elongated spermatids were retained in the seminiferous epithelium and many round spermatids could be seen in the epididymal ducts. At day 12, a looser arrangement of spermatids and spermatocytes became evident, with apparent narrow empty spaces being formed between germ cells in an approximately radial direction towards the tubule lumen; the numbers （per testis） of non-type B spermatogonia and spermatocytes were similar to controls, whereas that of type B spermatogonia increased by 59%, and that of early round, elongating and late elongated spermatids decreased by 37%, 72% and 52%, respectively. Conclusion： The primary spermatogenic lesions following EDS administration were （i） spermiation failure and （ii） detachment of spermatids and spermatocytes associated with impairment in spermiogenesis and meiosis.     

Quantitative （stereological） study of incomplete spermatogenic suppression induced by testosterone undecanoate injection in rats

Aim: To evaluate the key lesions in spermatogenesis suppressed partially by testosterone undecanoate(TU) treatment. Methods: Adult male SD rats were treated with vehicle or TU (19 mg/kg) injection (i.m.) every 15 days for 130 days. The numbers of all types of cells (nuclei) in the seminiferous tubules and the interstitial tissue were estimated using a contemporary stereological tool, the optical disector. Results: In response to TU treatment, the numbers of non-type B spermatogonia, type B sperrnatogonia and late elongated spermatids per testis were reduced to 51%, 66% and 14% of the controls, respectively. The conversion ratios from type B spermatogonia to early spermatocytes and pachytene spermatocytes were not significantly affected and the ratios to the later germ cell types fell to 51%-65% of the controls. Less than 1.0 % of immature round spermatids were seen sloughing into the tubule lumen, 4.0% of elongated spermatids retained in the seminiferous epithelium, and about half of the elongated spermatid nuclei appreciably malformed. Leydig cells were atrophied but their number and the peritubular myoid cell number per testis were unchanged. Conclusion: Double inhibition of spermatogenesis (i.e. inhibition at spermiation and spermatogonial conversion to type B spermatogonia), a scenario seen in the monkey and human following gonadotrophin withdrawal, was not sufficiently effective for a complete spermatogenic suppression in the rat after TU treatment, probably due to ineffective inhibition of the Leydig cell population and therefore the intra-testicular test-osterone levels. (Asian J Androl 2004 Dec; 6: 291-297)     

Development of stage-specific paracrine regulation of Leydig cells by the seminiferous tubules

The size of peritubular Leydig cells surrounding tubules in different stages of the spermatogenic cycle was determined in 43- and 47-day-old male rats. A stage-dependent variation in the size of peritubular Leydig cells was not present in 43-day-old rats, but by 47 days those Leydig cells closely adjacent to tubules at stages VII-VIII were larger than others. At 43 days of age spermatogenesis had developed up to step 18 spermatids in late stage VI tubules. At 47 days of age the first mature sperm had just been released from the seminiferous epithelium, and consequently the first wave of the spermatogenic cycle was completed. Tubules at stages VII-VIII therefore acquire the ability to influence surrounding Leydig cells when they contain step 19 spermatids. It remains to be shown whether this maturation step is due to inherent maturation of the Sertoli cells or if step 19 spermatids specifically modulate Sertoli cell function.     

抑制素B βB亚单位在不同病理分型的无精子症患者睾丸组织中的表达

目的:探讨抑制素B(INH B)βB亚单位在不同生精功能状态的人睾丸组织中的表达情况。方法:对83例无精子症患者进行睾丸组织病理检查诊断,根据病理形态的不同分为:唯支持细胞综合征型(n=21);生精功能低下型(n=20);生精阻滞型(n=24);生精功能基本正常型(n=18)。选择上述各型结构完整的睾丸组织,分别应用免疫组化法(SP)对血清INH B βB亚单位在不同生精功能状态的睾丸组织,进行定位研究。结果:各型睾丸组织内均存在血清INH B βB的表达,其分布特点为:间质细胞(Leydig cell)和早期生精细胞多为强阳性表达,呈深棕黄色;支持细胞(Sertoli cell)多为阳性表达;而晚期精子细胞和成熟精子未见表达;生精小管管周类肌细胞呈弱阳性表达。结论:INH B可能是睾丸Sertoli细胞和早期生精细胞的一个联合产物。     

实验性精索静脉曲张对青春期大鼠睾丸、附睾中CRES蛋白表达的影响

目的:研究青春期大鼠实验性左侧精索静脉曲张(ELV)对睾丸和附睾中胱蛋白酶抑制剂相关的附睾精子发生(CRES)蛋白表达的影响,探索精索静脉曲张导致不育的机制。方法:建立青春期雄性SD大鼠ELV模型,采用免疫组化及蛋白印迹方法检测CRES蛋白在ELV 2周组(n=8)、4周组(n=8)及其相应的对照组(n均=5)大鼠睾丸和附睾头、体、尾中的表达变化。结果:免疫组化显示,CRES蛋白在ELV实验组和对照组大鼠睾丸和附睾中均有表达。在睾丸中,CRES蛋白主要定位于圆形和长形精子细胞的胞质、精子的顶体以及残余体中,其表达与生精周期密切相关,Ⅰ~Ⅲ和Ⅸ~ⅩⅣ期表达最强,Ⅶ~Ⅷ期表达次之,Ⅳ~Ⅵ期表达减弱。在附睾中,CRES蛋白主要表达于从附睾起始段到尾部的上皮主细胞的胞质中,且以体、尾部表达最强,头部次之,管腔分泌物也呈阳性表达。实验组比对照组CRES蛋白表达增强。W estern印迹显示:实验组和对照组大鼠睾丸和附睾在相对分子质量(Mr)为19 000和14 000处均可见CRES蛋白条带,其中以Mr19 000处表达更为明显。实验组CRES蛋白的表达比对照组明显增强。对免疫组化和W estern印迹结果进行灰度值和积分吸光度值(IA)测定,并经统计学分析显示:ELV 2周组和4周组比其相对应的对照组表达增强且差异有显著性(P<0.05或P<0.01),而ELV各组间未见CRES蛋白表达有明显差异(P>0.05)。结论:CRES蛋白在大鼠睾丸和附睾中均有表达,睾丸中表达呈现生精周期特异性和细胞特异性,附睾中表达呈现附睾上皮区段和细胞特异性;CRES蛋白在青春期ELV大鼠睾丸和附睾中的表达比对照组明显增强。这些结果提示CRES蛋白在精子发生和精子成熟过程中可能起着重要的作用,并且可能与ELV引起的不育或生育力低下有关。     

Expression profile of Toll-like receptor 4 in rat testis and epididymis throughout postnatal development

Toll-like receptors (TLRs) belonging to pattern recognition receptors are involved in maintaining testicular and epididymal immune homeostasis. The purpose of the current study was to investigate TLR4 expression in rat testis and epididymis throughout postnatal development. Weak staining was detected in peritubular myoid cells and immature Sertoli cells while no staining was observed in gonocytes during prepubertal period. However, TLR4 expression began to appear in spermatocytes in pubertal period and gradually increased in spermatids. An intense staining was observed in steps 5–19 spermatids in post pubertal and mature periods. Similarly, TLR4 expression in the testes steadily increased from pubertal period to mature period. Puberty also caused a significant increase in TLR4 expression in epididymis. TLR4 expression in cauda epididymis was lower as compared to those of other epididymal segments. The majority of epididymal epithelial cells exhibited apical TLR4 expression, whereas basal cells showed intense intracytoplasmic immunoreaction. We detected an intense staining in epididymal smooth muscle cells. The expression levels of TLR4 showed dynamic changes in both spermatogenic cells, and entire testicular and epididymal tissues during postnatal development. These results suggest that TLR4 expression contributes not only to inflammation but also to the development of spermatogenic cells.     

Attractin蛋白在大鼠睾丸和附睾中的免疫组织化学定位

目的 :探讨Attractin蛋白在成熟大鼠睾丸和附睾组织中的分布。　方法 :健康成年雄性SD大鼠 2 0只 ,灌流取睾丸和附睾组织固定 ,石蜡包埋和冰冻切片。用免疫组化法和间接免疫荧光方法检测Attractin蛋白在成熟大鼠睾丸和附睾组织中的表达。　结果 :睾丸组织间质细胞、睾丸精曲小管管周肌样细胞和各级生精细胞 (精原细胞、初级精母细胞和精子细胞 )、支持细胞呈阳性反应 ,主要表达于胞膜及胞质。睾丸间质细胞表达略强于生精细胞。附睾头、体、尾均未见表达。　结论 :Attractin蛋白在成熟大鼠睾丸组织间质细胞和生精细胞中有较强的表达 ,其生理功能尚有待进一步探讨。     

Specific localization of RBM1a in the nuclei of all cell types except elongated spermatids within seminiferous tubules of the human

Recent studies have indicated that at least three regions (AZF a-c) on the long arm of the Y-chromosome code for factors are involved in spermatogenesis. One of the candidate genes in the AZFb region is RBM1a, coding for a protein with an RNA binding motif. In this study, poly clonal antibodies raised against a 15 amino acid peptide, corresponding to residues 263-304 of the deduced amino acid sequence of RBM1a, has been used to localize the RBM1a protein in the human testis. Immunohistochemistry on normal human testis using this RBM1a antibody, localized the antigen to the nuclei of spermatogonia, primary spermatocytes, and round spermatids but not to the nuclei of elongated spermatids. The antibody also specifically identified the nuclei of Sertoli cells, although the fluorescence was not as strong as in the germ cell nuclei it identified. No specific fluorescence was seen in the nuclei of either peritubular, endothelial or Leydig cells. Western blot of normal human testicular tissue using the anti-RBM1a antibody gave rise to a single specific band of approximately 55 kDa, corresponding to the expected size of RBM1a. In view of its expression in germ cells, and because RBM1a has an RNA binding domain, RBM1a may be involved in RNA processing, such as RNA splicing or RNA export which are events necessary for normal spermatogenesis.     

Localization of integrin β1, α1, α5 and α9 subunits in the rat testis

Very late activation ( VLA, β₁; α₁; α₅, α₉) integrins were studied by immunoblotting and immunohistochemistry in the testes of sexually mature rats. All integrin subunits were present in membrane fractions of homogenized testes. Immunohistochemistry revealed that the anti β₁ antibody recognized peritubular cells and the basement membrane of blood vessels. Immunoreactivity was also demonstrated in the lamina propria, basement membrane, and the basal cytoplasm of Sertoli cells. In elongating spermatids, β₁ integrin was localized to the acrosome. The α₁ subunit was expressed in peritubular cells and in the lamina propria. In the adluminal compartment, round spermatids were stained diffusely for the α₁ subunit. Immunoreactivity for α₁ integrin was found additionally in the acrosomes of elongating spermatids shortly before their release into the seminiferous tubule lumen. The α₅ subunit was expressed in the acrosomes of elongating spermatids as well as in their distal cytoplasm during stages III–VI; the cytoplasmic lobes of elongate spermatids and/or residual bodies also appeared to be immunostained in seminiferous tubules at stages VII–VIII. The α9 subunit was immunolocalized only in the basement membrane and in peritubular cells. These data suggest that integrins are involved in spermatogenesis, in particular in the process of spermatid maturation.     

Follicle-stimulating hormone and testosterone stimulation of immature and mature Sertoli cells in vitro: inhibin and N-cadherin levels and round spermatid binding.

The in vitro response of Sertoli cells isolated from adult rat testes to testosterone (T) and follicle-stimulating hormone (FSH) treatment was investigated. Sertoli cells from >70-day-old Sprague-Dawley rats were isolated by a combined enzymatic treatment followed by the removal of the majority of contaminating germ cells with immobilized peanut agglutinin lectin. Sertoli cells were then cultured for 6-10 days, forming a confluent layer with a cell viability of >83% and 74-77% purity. The contaminating cells were peritubular cells (4-6%), pachytene spermatocytes (4-5%), round spermatids (<2%), elongated spermatids (<1%), and degenerating germ cells (14.8%). The proportion of degenerating germ cells decreased from 14.8% to 8.6% between days 6 and 10 in culture. After a prestimulation culture period of 4 days, FSH treatment over a 2-day period resulted in a dose-related increase of inhibin with a median effective dose (ED50) value of 36.7+/-20.4 ng/ml in comparison with an ED50 value of 4.4+/-0.9 ng/ml obtained with immature Sertoli cell cultures from 20-day-old rats. Mature Sertoli cells, in contrast to immature Sertoli cells, were unresponsive to combined FSH + T treatment for the production of the cell adhesion protein N-cadherin. FSH treatment promoted the in vitro binding of round spermatids isolated from adult testis to adult Sertoli cells in coculture. It is concluded that mature Sertoli cells in culture are responsive to FSH in terms of inhibin production and round-spermatid binding. The lack of an FSH + T-induced increase in N-cadherin or round spermatid binding is attributed to either a reduced sensitivity, or an alteration in the regulation of mature Sertoli cells by FSH + T.     

Phosphorylation of mitogen-activated protein kinase 8 (MAPK8) is associated with germ cell apoptosis and redistribution of the Bcl2-modifying factor (BMF)

Successful spermatogenesis requires that germ cells remain in physical contact with Sertoli cells until spermiation. Previous studies have shown that the Bcl2-modifying factor (BMF) is a proapoptotic protein found in many epithelial cells which, when phosphorylated by the active form of mitogen-activated protein kinase 8 (p-MAPK8), initiates apoptosis in response to loss of adhesion of the cells to their basal lamina. Based on this, we hypothesized that p-MAPK8 and BMF may play important roles in the apoptotic death of testicular germ cells in response to their detachment from Sertoli cells. Immunohistochemical analysis of the normal rat testis revealed p-MAPK8 expression in spermatocytes and elongated spermatids but not in round spermatids. This localization was opposite to that of BMF, which is expressed in round spermatids but not in spermatocytes or elongated spermatids. When freshly isolated germ cells were cultured in the absence of Sertoli cells, a condition in which there was widespread germ cell apoptosis, an increase in p-MAPK8 relative to overall MAPK8 protein, was seen by Western blot analysis. Additionally, immunocytochemical analysis showed an increase in immunoreactive p-MAPK8 in round spermatids and spermatocytes in association with BMF expression. From these correlative data, we propose that the activation of MAPK8 and redistribution of BMF may be integrally involved in the mechanism by which specific germ cells undergo programmed cell death in response to their detachment from Sertoli cells.     

实验性精索静脉曲张对青春期大鼠睾丸、附睾精子结合抗原11 mRNA及其蛋白异构体表达的影响

目的:研究实验性左侧精索静脉曲张(ELV)对青春期大鼠睾丸和附睾中精子结合抗原11(SPAG11)mRNA及其蛋白异构体SPAG11E表达的影响,并探讨其与精索静脉曲张导致男性不育的关系。方法:40只SD大鼠随机分为ELV2周组、4周组,假手术对照2周组、4周组,每组10只。ELV组行部分结扎左肾静脉建立青春期SD大鼠ELV模型,假手术对照组仅显露左肾静脉过程,但不结扎。应用RT-PCR和免疫组化法(n=5)检测SPAG11 mR-NA及SPAG11E蛋白在ELV2周组和ELV4周组及各自对照组大鼠双侧睾丸、附睾中的表达变化。结果:RT-PCR结果显示,SPAG11基因376bp的特异扩增产物仅见于大鼠附睾组织中。免疫组化结果显示,SPAG11E蛋白主要与睾丸生精上皮的圆形和长形精子细胞的顶体泡和顶体、睾丸间质细胞的胞质相结合;在附睾管上皮主细胞胞质和顶部静纤毛中表达。对RT-PCR的相对吸光度值和免疫组化的灰度值进行统计学分析显示:①左侧附睾ELV2周和4周组SPAG11 mRNA和SPAG11E蛋白的表达与各自右侧组及各自对照组比较均有显著减弱(P<0.05或P<0.01);左侧附睾ELV4周组SPAG11mRNA与SPAG11E的表达较ELV2周组显著减少(P<0.05或P<0.01);右侧附睾ELV4周组SPAG11E的表达也较ELV2周组显著减少(P<0.01);②两实验组双侧睾丸SPAG11E蛋白的表达与相应对照组比较均未见明显差异(P>0.05),且在ELV2周组和ELV4周组之间该蛋白的表达也无显著性差异(P>0.05)。结论:SPAG11是特异表达于附睾的基因,在大鼠睾丸和附睾中均可见其蛋白异构体SPAG11E免疫阳性反应,其定位及表达水平具有细胞特异性和区域特异性,而且SPAG11 mRNA及SPAG11E蛋白在ELV模型鼠附睾中的表达发生了明显变化,这提示SPAG11不仅可能在大鼠精子发生、成熟过程中发挥重要作用,还可能与精索静脉曲张所致的男性不育相关。     

一氧化氮合酶在食蟹猴睾丸及附睾中的表达及意义

目的:探索一氧化氮合酶(NOS)在食蟹猴睾丸及附睾中的表达及意义。方法:运用免疫组化染色法观察NOS在8只猴龄为8岁左右性成熟食蟹猴睾丸及附睾中的分布。结果:①神经元型NOS(nNOS)免疫反应阳性见于睾丸生精小管上皮内各级生精细胞、腔内精子、附睾输出小管上皮、血管内皮细胞。②诱导型NOS(iNOS)免疫反应阳性见于附睾输出小管上皮、腔内精子、管周类肌细胞、血管内皮细胞。③内皮型NOS(eNOS)免疫反应阳性见于睾丸间质细胞、附睾输出小管上皮、腔内精子、管周类肌细胞、血管内皮细胞。结论:NOS广泛表达于性成熟食蟹猴睾丸及附睾组织细胞中,推测其在参与精子发生、成熟及睾丸激素分泌等过程中起到重要作用。     

幼年猪全阴囊Ⅲ度烧伤创面早期植皮修复对睾丸Survivin蛋白表达的影响

目的探讨幼年猪全阴囊Ⅲ度烧伤后早期植皮修复阴囊对睾丸生精功能恢复的影响。方法取2月龄雄性贵州小型猪30只,体重10～15 kg;随机分为3组,每组10只,分别为正常对照组(A组)、自然愈合组(B组)、植皮组(C组)。A组小型猪不作任何处理;B、C组小型猪制备阴囊Ⅲ度烧伤模型后,B组不作处理,待其自行愈合;C组切除烧伤阴囊皮肤,取下腹部全厚皮植皮修复。术后观察B、C组实验动物一般情况,并于模型制备3个月(实验动物已成年)及1年每组分别取5只实验动物双侧睾丸标本,HE染色观察不同方式修复阴囊对睾丸生精细胞的形态学影响,免疫组织化学染色检测Survivin蛋白表达。结果实验动物均存活至实验完成,创面均顺利愈合。组织学观察示A组各级生精细胞形态正常,管腔中可见成熟精子;B组生精上皮明显变薄,仅1～2层生精细胞;C组生精细胞较B组稍多,部分可见精子细胞;术后1年B、C组生精细胞较3个月时增加。免疫组织化学染色示术后3个月及1年B、C组Survivin蛋白表达少于A组,B组少于C组,差异均有统计学意义(P<0.05);组内两时间点比较,差异均无统计学意义(P>0.05)。结论植皮修复全阴囊Ⅲ度烧伤创面对猪睾丸生精功能有抑制作用,可导致生精细胞减少,Survivin蛋白表达降低,但生精小管内仍有部分精子细胞残存。