The vanishing testis: diagnosis and histological findings

PURPOSE: Controversy exists on how to diagnose the vanishing testis and the degree of investigation required. In this series, we reviewed anatomical and histological findings in vanishing testes and investigated the effectiveness of diagnostic laparoscopy and imaging studies. MATERIALS AND METHODS: Between 1974 and March 1999, 107 boys with nonpalpable testis underwent surgery. Of the total, 52 had spermatic vessels, vas deferens, and/or nubbin, and as a result the diagnosis of vanishing testis was made. RESULTS: The affected side of vanishing testis was left 41, right 9 and bilateral 2.35 nubbins were found and the lengths of 24 nubbins were 5 mm or less. Histological examinations were performed in 43 cases including 27 nubbins. From that total, 31 had vas deferens and 11 had epididymis. Only two nubbins had seminiferous tubules but they included no germ cells. The two nubbins were greater than 5 mm long. Laparoscopic surgery was undertaken in 12 separate cases of the vanishing testis and as a result hypoplastic spermatic vessels were present in 7 of the 12 cases. CONCLUSION: The incidence of viable testicular tissue in vanishing testes was 4.7% in our series and it ranges from 0-16% in other series. We submit that one can diagnose the inguinal vanishing testis with preoperative imaging and laparoscopy, and that the nubbin seldom contains testicular tissue. Our results do not support the necessity to remove nubbins.     

Exploration for testicular remnants: implications of residual seminiferous tubules and crossed testicular ectopia

PURPOSE: Testicular remnants identified during exploration for cryptorchidism contain vascularized fibrous nodules at the termination of the vas deferens, hemosiderin, calcification, a pampiniform plexus or occasionally residual seminiferous tubules that may contain germ cells. An absent testis lacks the features of testicular remnants. To our knowledge testicular remnants have not been described in a crossed ectopic location. We reviewed orchiectomy specimens obtained at exploration for a nonpalpable testis to characterize the features of testicular remnants, including the frequency of seminiferous tubules, germ cells and crossed ectopia, as well as to clarify the diagnostic criteria for testicular remnants. MATERIALS AND METHODS: From 1990 to mid 2000 medical records and histological slides from 101 boys with nonpalpable testes who had undergone inguinal exploration and orchiectomy were reviewed. RESULTS: Of the 71 testicular remnants identified 7 (9.8%) contained residual tubules, of which 4 (5.6%) contained germ cells. In 4 boys the testis was deemed absent but 3 did not undergo laparoscopic exploration. There were 2 ectopic remnants (2.8%) on the contralateral side-the pelvis or in the scrotum. Both crossed remnants demonstrated dissociation of the testis from the vas/epididymis which remained on the correct side associated with a pampiniform plexus. No müllerian remnants were encountered. CONCLUSIONS: Adequate exploration for nonpalpable testis requires laparoscopy with visualization of the contralateral pelvic region because an ectopic remnant may be dissociated from the vas/epididymis and vessels. Identification of a pampiniform plexus, vas and spermatic vessels may not be a reliable indicator of a testicular remnant. Continued removal of testicular remnants is warranted because at least 9.8% contain residual viable tubules.     

睾丸精曲小管精子发生功能量化评价法分析无精子症患者睾丸生精功能

目的 :分析无精子症患者临床和病理资料 ,研究病理学量化评价睾丸精曲小管精子发生功能的方法的临床意义。　方法 :无精子症患者 112例 ,年龄 2 2～ 4 6 (2 9.0± 4 .4 )岁 ,婚龄 2～ 12 (4 .0± 2 .8)年、病程 2～ 6 (2 .70±1.0 2 )年 ,其中原发性无精子症 96例 ,继发性无精子症 16例 ;梗阻性无精子症 7例。不育症患者精液常规检查 3次确认无精子症 ,检测性激素水平 ,常规消毒下睾丸活检病理检查 ,在高倍镜下计数每个精曲小管中各类生精细胞数 ,测定小管直径、生精上皮高度和固有层厚度 ,按制定的精曲小管精子发生功能 10分 5级分度法加以评分 ,进行统计学分析。　结果 :精曲小管生精上皮 10分分度法评分结果 ,1分 5例 (4 .5 % ) ,2分 38例 (33.9% ) ,3分 2例(1.8% ) ,4分 6例 (5 .4 % ) ,5分 2例 (1.8% ) ,6分 17例 (15 .2 % ) ,7分 6例 (5 .4 % ) ,8分 19例 (17% ) ,9分 10例(8.9% ) ,10分 7例 (6 .3% )。精曲小管精子发生功能 5级分度法结果 ,1级 5例 (4 .5 % ) ,2级 38例 (33.9% ) ,3级 33例 (2 9.5 % ) ,4级 2 9例 (2 5 .9% ) ,5级 7例 (6 .3% )。多元回归分析结果 ,精曲小管精子发生功能分级与生精上皮高度、固有层厚度、精曲小管直径和血清卵泡刺激素 (FSH)具有极显著相关性 (P <0 .0 1)。组合     

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。     

Infancy is not a quiescent period of testicular development

Postnatal evolution of the testis in most laboratory animals is characterized by the close continuity between neonatal activation and pubertal development. In higher primates, infancy, a long period of variable duration, separates birth from the beginning of puberty. This period has been classically considered as a quiescent phase of testicular development, but is actually characterized by intense, yet inapparent activity. Testicular volume increases vigorously shortly after birth and in early infancy due to the growth in length of seminiferous cords. This longitudinal growth results from active proliferation of infantile Sertoli cells which otherwise display a unique array of functional capabilities (oestrogen and anti-müllerian hormone secretion, increase of FSH receptors and maximal response to FSH). Leydig cells also show recrudescence after birth, possibly determined by an active gonadotrophic-testicular axis which results in increased testosterone secretion of uncertain functional role. This postnatal activation slowly subsides during late infancy when periodic phases of activation of the hypothalamo-pituitary-testicular axis are paralleled by incomplete spermatogenic spurts. The beginning of puberty is marked by the simultaneous reawakening of Leydig cell function and succeeding phases of germ cell differentiation/degeneration which ultimately lead to final spermatogenic maturation. The marked testicular growth in this stage is due to progressive increase at seminiferous tubule diameter. Sertoli cells, which have reached mitotic arrest, develop and differentiate, establishing the seminiferous tubule barrier, fluid secretion and lumen formation, and acquiring cyclic morphological and metabolic variations characteristic of the mature stage. All of these modifications indicate that, far from being quiescent, the testis in primates experiences numerous changes during infancy, and that the potential for pubertal development and normal adult fertility depends on the successful completion of these changes.     

睾丸细胞生物学研究进展

睾丸是男性生殖腺,由生精小管和间质构成。生精小管主要由生精细胞和支持细胞组成,是精子发生场所;间质中主要是间质细胞,间质细胞合成与分泌雄激素。本文介绍睾丸3种细胞的发育分化,以及成年期睾丸细胞的结构和生物学研究进展。     

De novo morphogenesis of seminiferous tubules from dissociated immature rat testicular cells in xenografts

Testicular development is initiated with the differentiation of Sertoli cells in the embryonic gonad. The aggregation of Sertoli cells is crucial for the generation of testicular cords and thus for the first sign of male gonadal development. To date, functional testicular tissue has not yet been generated in vitro. The objective of this study was to explore the de novo morphogenesis of testicular tissue from isolated postnatal rat testicular cells using a combination of in vitro culture and ectopic xenografting. Immature rat testicular cells were cultured in either a 2-dimensional (laminin-coated coverglass) or a 3-dimensional (extracellular matrix gel) culture system. Whereas testicular cells cultured on laminin showed a slow morphogenetic cascade resulting in cord formation after about 10 days of culture, cells cultured on extracellular matrix gel assembled to a network of cordlike structures within several hours after plating and formed spherical cell aggregates at day 3. Further progression of the morphogenetic cascade was not obtained in either the 2- or the 3-dimensional culture system. In contrast, structures resembling immature testicular tissue were obtained after xenografting of extracellular matrix gel-enclosed spherical testicular cell aggregates. The grafts were vascularized and contained elongated seminiferous tubules. Histologic analysis revealed the presence of a basement membrane, a histologically normal interstitium containing putative Leydig cells, the establishment of tubule lumen, and the integration of few putative spermatogonia into the seminiferous epithelium. We conclude that immature rat testicular cells carry the full potential to generate all somatic components of a testis in xenografts, thus opening fascinating pathways to study testicular organogenesis.     

Evaluation of blood–testis barrier integrity in terms of adhesion molecules in nonobstructive azoospermia

Blood–testis barrier (BTB) is critical for maintaining fertility. The integrity of tight junctions (TJs) provides restricted permeability of BTB. The aim of this study was to evaluate the relationship between BTB and Sertoli cells. Testicular sperm extraction (TESE) obtained from nonobstructive azoospermia (NOA) patients was examined: Group I (spermatozoa + ) and Group II (spermatozoa − ). The tissues were stained with haematoxylin eosin, periodic acid–Schiff and Masson's trichrome for Johnsen's score evaluation. Apoptosis and adhesion molecules such as claudin-11, occludin and ZO-1 were assessed. In Group I, the integrity of the seminiferous tubules was intact. In Group II, some seminiferous tubule walls were lined only with Sertoli cells, had a thickening of the basement membrane, and oedema in interstitial spaces. In Group I, the seminiferous tubule consisted of a stratified columnar epithelium, claudin-11 expressions were observed as linear staining in the basal zone of the tubule, while seminiferous tubules, with low epithelium, displayed a punctate type of staining. Immunohistochemical observations were consistent with the ultrastructural findings. In Group II, high apoptosis and unstained/irregular TJ formation in claudin-11, occludin and ZO-1 were observed. In conclusion, disruption of relation between BTB and TJs may reveal inadequate spermatogenesis, which is one of the mechanisms behind azoospermia.     

Studies on relationship between testicular capsule and sperm transport in rat testis

Aim: In SD rats, histological changes in the testis were observed after bilateral capsulotomy (of the tunica albuginea) in order to investigate the physiological role of the testicular capsule on sperm transport. Methods: Bilateral longitudinal capsulotomy was devised to disrupt the capsular contractile function. With this technique, only the tunica vaginalis and tunlca albuginea were slit open, leaving the tunica vasculosa intact to embrace the underlying testicular parenchyma. After capsulotomy, the structural changes in the seminiferous tubules, the transitional distal seminiferous segment, and the rete testis were observed. Results: In the capsulotomized testis, there was sperm retention at the transitional seminiferous segment and progressive degenerative changes in seminiferous tubules. Conclusion: The results clearly indicated that an intact testicular capsule was required for normal sperm transport from the seminiferous tubules into the rete testis. This is the first attempt to study the physiological role of the testicular capsule in intact animals.     

Immunohistochemical distribution of S-100 protein and subunits (S100-alpha and S100-beta) in the swamp-type water buffalo (Bubalus bubalis) testis

The distribution and localization of S-100 protein (S-100) and its subunits (S100-alpha and S100-beta) in the testis of swamp-type water buffalo were investigated using immunohistochemistry. S-100 was detected in the Sertoli cells in the convoluted seminiferous tubules, modified Sertoli cells lining the terminal segment of the seminiferous tubules and in the intratesticular excurrent ducts (straight tubules and rete testis). S100-beta showed the same distribution and localization with that of S-100. However, the cytoplasmic extension of the Sertoli cells in S100-beta staining showed less staining intensity compared with that of S-100. S100-alpha showed a positive staining only in the modified Sertoli cells of the terminal segment of the seminiferous tubule. Endothelial cells of blood vessels were also positive with the proteins while the Leydig and spermatogenic cells showed a negative reaction. The localization of S-100 in the testis of the water buffalo was in parallel with that of other artiodactyls which supports the hypothesis that this protein is a multifunctional protein. S100-beta in the Sertoli cells suggests that this protein is involved in establishing blood-testis barrier. Its presence in the modified Sertoli cells and in the epithelium of the excurrent ducts suggest secretory and absorptive function, respectively. Meanwhile, S100-alpha, which was detected only in the modified Sertoli cells, is involved in the secretory activity of these cells that are related to exocrine function.     

Seminiferous tubule degeneration in human cryptorchid testes

Two types of degenerating seminiferous tubules were found in cryptorchid testes with Sertoli cell hyperplasia of children and adults: 1) tubules with central degeneration, and 2) tubules with total degeneration. Central degeneration begins with degenerative changes in germ cells that accumulate in the lumen of the seminiferous tubule. Some Sertoli cells may also be affected. Degenerated cells finally disappear, and the remaining tubule is composed of only a cuboidal epithelium, which consists mainly of Sertoli cells and occasional germ cells surrounding a wide lumen. Total degeneration is principally seen in tubules with severe germinal hypoplasia. All the seminiferous epithelium cells degenerate and lose their characteristic distribution, forming a disorganized Sertoli cell nodule surrounded by a thickened basement membrane. Lastly, Sertoli cells disintegrate, and the seminiferous epithelium disappears. Tubular degeneration might be related to the thickening of the basement membrane, which hinders metabolic interchange between the seminiferous epithelium and the interstitium.     

The rat testis produces large amounts of an interleukin-1-like factor

Homogenates of whole testis, isolated seminiferous tubules, testicular cytosol, conditioned media from seminiferous tubules obtained from intact or cryptorchid rats, as well as seminiferous tubules devoid of peritubular cells, showed high concentrations of interleukin-1 (IL-1). Cytosol from spleen showed low IL-1 activity, while no activity was found in cytosol from heart, kidney, prostate, ovary or liver. Interleukin-1 activity was not detected in spent medium from cultures of immature Sertoli cells (10-day-old rats) or from peritubular cells or in homogenates of interstitial cells from adult rats. Ultrogel AcA 44 gel chromatography and HPLC size exclusion chromatography exhibited a single peak of IL-1 activity corresponding to a relative molecular mass of 17,000-20,000 (Mr = 17-20 K). Similarly, chromatofocusing revealed only one peak of activity with an apparent isoelectric point of 5-6. It is concluded that the rat testis contains large amounts of an IL-1 alpha-like factor. The adult Sertoli cell or possibly germ cells are suggested as its primary source. Testicular IL-1-like activity is of particular interest in view of the intense cell proliferation during spermatogenesis, and the tendency to testicular relapse of acute lymphoblastic leukaemia.     

Bilateral prepubertal testicular biopsies predict significance of cryptorchidism-associated mixed testicular atrophy, and allow assessment of fertility

INTRODUCTION: Mixed atrophy of the testis (MAT), a frequent finding in biopsies of formerly cryptorchid and/or infertile patients, is defined as the synchronous occurrence of both seminiferous tubules containing germ cells and Sertoli cell only-tubules in variable proportions. In tubules containing germ cells, different types of abnormalities in spermatogenesis may be seen. The presence of adult spermatids in the biopsy, even in small numbers, correlates with successful spermatozoa retrieval for "in vitro" fertilization techniques. Currently, it is unknown whether precursor lesions of MAT can be identified in cryptorchid patients during childhood. MATERIAL AND METHODS: Eighteen formerly cryptorchid adults who had undergone testicular biopsies in childhood had a repeat testicular biopsy to evaluate infertility. In prepubertal biopsies, abnormalities of the testicular parenchyma were classified into types I (slight alterations), II (marked germinal hypoplasia), and III (severe germinal hypoplasia). In postpubertal biopsies, the percentage of tubules containing germ cells and Sertoli cell only-tubules were estimated, as well as the presence of complete spermatogenesis. Abnormalities in spermatogenesis were classified into lesions of the adluminal or basal compartments of seminiferous tubules. RESULTS: Comparison between prepubertal and postpubertal biopsies revealed that most specimens developing from type III lesions presented with incomplete spermatogenesis (P<0.0001) and more severe lesions of the germinal epithelium (P=0.049). DISCUSSION: Type III lesions correlated with MAT characteristics that confer a worse prognosis for in vitro fertilization. Thus, MAT characteristics may be predicted in prepubertal cryptorchid patients, allowing a fertility prognosis. The pathogenesis of these lesions, and their possible inclusion into the spectrum of the testicular dysgenesis syndrome, are discussed.     

Immunohistochemical expression of cyclin A in testicular biopsies of fertile and infertile men: correlation with the morphometry of seminiferous tubules

Cyclin A is a member of the cyclin family of proteins, which are required for both the mitotic and meiotic divisions that characterise spermatogenesis in human and other mammalian species. The data on cyclin A expression in various human spermatogenic disorders and its relationship to the morphology of seminiferous tubules are not well clarified. This study aimed to evaluate the immunohistochemical expression of cyclin A in testicular biopsies of different spermatogenic disorders correlating with the morphology of seminiferous tubules using morphometry tools. Immunohistochemical evaluation of cyclin A was carried out on testicular biopsies obtained from 48 infertile males (nonobstructive azoospermia) and 15 normal subjects together with using semiautomatic morphometric analysis for evaluation of seminiferous tubules. Cyclin A is expressed in 100% of normal and hypospermatogenesis groups and in 80% of maturation arrest group, with complete absence in Sertoli cell only group. In positive cases, cyclin A stained the nuclei of spermatogonia and primary spermatocytes with a higher intensity of expression in normal cases compared with infertile group. Cyclin A expression was significantly associated with the different examined morphometric parameters. Cyclin A is involved in both mitosis and meiosis of human spermatogenesis as it is expressed in spermatogonia and primary spermatocytes. Morphometry of human testis is intimately correlated with the testicular histopathology.     

Carnosine mitigates apoptosis and protects testicular seminiferous tubules from gamma‐radiation‐induced injury in mice

This study investigated the radioprotective effects of a naturally occurring dipeptide, carnosine, on testicular damage. Carnosine was administered (10, 50 and 100 mg kg^?1 body weight) to male mice via intraperitoneal injection for 4 days prior to gamma irradiation (2 Gy). Apoptosis with the TUNEL assay and histopathological parameters were evaluated 12‐h and 14‐day post‐irradiation. Pre‐treatment with carnosine before irradiation significantly reduced the frequency of TUNEL‐positive cells induced by radiation treatment at all doses by reduction factors of 1.8, 2.47 and 2.23 for carnosine at 10, 50 and 100 mg kg^?1 bw, respectively, unlike that observed in the radiation alone group. Exposure to ionising radiation decreased sperm count and reduced the height and diameter of seminiferous epithelial tubules. Pre‐treatment with all doses of carnosine significantly augmented seminiferous epithelial height and tubule diameter and also increased the number of germinal cells in comparison to the group treated with radiation only. These results indicate that carnosine prevents testicular dysfunction induced by gamma‐irradiation via an anti‐apoptotic effect; this restoration of proper testicular function ultimately leads to the recovery of spermatogenesis.     

Attractin蛋白在不同病理分型无精子症患者睾丸组织中的表达

目的探讨Attractin蛋白在不同生精功能状态的人睾丸组织中的表达情况。方法对31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=4),生精功能低下型(n=12),生精阻滞型(n=5),生精功能基本正常型(n=10)。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)观察Attractin蛋白在不同生精功能状态的睾丸组织中的表达。结果各组睾丸组织内均存在Attractin蛋白的表达,其分布特点为:睾丸生精小管和间质细胞、管周肌样细胞、支持细胞上均有Attractin蛋白的表达,主要表达于胞膜和胞质,胞膜表达强于胞质。Leydig细胞、Sertoli细胞、精原细胞、精母细胞及精子细胞均为阳性表达,呈棕黄色着染。Attractin的表达与生精功能有关,正常组表达明显高于其它组,唯支组表达明显低于其他组。结论 Attractin蛋白与男性生殖密切相关,但其具体作用环节尚有待进一步研究。     

S-100 Protein immunoreactivity in bovine testis

The present study deals with immunohistochemical localization of S-100 protein in the bovine testis. Immunoreactivity for the protein was seen in Sertoli cells of the seminiferous tubules and as a particularly intense staining in the terminal tubular segment (transitional region, middle portion, and terminal plug), which is mainly composed of modified Sertoli cells. Immunoreactivity was also found in epithelial cells of the straight testicular tubules and rete testis, and in the endothelium of capillaries, veins and lymphatic vessels. Although the functional significance of S-100 protein immunoreactivity in the Sertoli cells remains unclear, the present results suggest that it may be involved in the microtubule assembly-disassembly system. The specificity of the immunolabelling observed should enable the antigen and/or antibody to S-100 to be used as an investigative and diagnostic tool in the study of bovine Sertoli cell function.     

小儿腹股沟不可触及睾丸的隐睾症诊治

目的:总结腹股沟不可触及睾丸的小儿隐睾症诊治经验。方法:回顾性分析收治腹股沟不能触及睾丸的隐睾患儿36例临床诊治资料。分析腹腔镜手术指征,腹股沟探查指征,术前超声检查的作用和术式的选择。结果:腹股沟不能触及的隐睾共36例(41侧),占总数的10.0%(36/361),经腹腔镜和腹股沟探查确定睾丸缺如18例(侧),腹内型隐睾16例(21侧),阴囊内睾丸残余2例(侧)。将腹腔镜下所见分4型,I型9例(侧),II型9例(侧)(其中IA型7例,IB型2例),III型11例(13侧),IV型7例(10侧)[其中IVA型5例(7侧),IVB型2例(3侧)]。分别采用经腹股沟睾丸下降固定,腹腔镜辅助睾丸下降固定术,分期Fowler-Stephen术。术前超声结果阳性诊断率为75%(27/36),睾丸缺如患儿对侧睾丸体积明显大于腹内型隐睾及睾丸残余患儿对侧睾丸体积。术后随访睾丸萎缩1例。结论:对于腹股沟未能查到睾丸的小儿隐睾症应行腹腔镜检查,腹腔镜下II型者,无需再行腹股沟探查,I型需探查腹股沟及阴囊。III型和IVB型可经腹股沟或腹腔镜辅助下行睾丸下降固定术,IVA型隐睾需在腹腔镜辅助下行睾丸下降固定或行分期Fowler-Stephen术。术前超声检查对侧睾丸大小有利于判断是否有睾丸缺如。     

新生小鼠睾丸组织和作为异种移植物的人类胎儿睾丸组织在免疫缺陷小鼠中的发育情况(英文)

目的:采用同种和异种睾丸组织移植的方法,研究新生小鼠睾丸组织及人类未成熟睾丸组织异种移植物在免疫缺陷小鼠体内发育不同时期生精细胞的组成和基因表达情况中生精细胞的发育情况。方法:以免疫缺陷小鼠为受体,新生小鼠睾丸组织和人类未成熟睾丸组织为供体,分别进行同种和异种移植。通过对移植物的组织形态学观察和分子生物学检测,对各个时期同种移植物中的生精细胞组成及其特异性基因的表达情况进行评估并与末受损小鼠的情况相比较;对人睾丸组织异种移植物的存活及其生精细胞在异体异位的发育情况进行探讨。结果:新生小鼠睾丸组织在成年雄性去势免疫缺陷小鼠体内的发育状况在移植开始的一个阶段与在体睾丸组织的发育情况基本相同,各级生精细胞的出现及其基因表达均与在体睾丸组织中相类似,而移植7-8星期后生精小管发生退化现象。人未成熟睾丸组织在受体中存活并且进一步生长;组织学观察还发现,生精细胞的发育速度与在体相比具有加速的倾向。结论:新生小鼠睾丸组织同种移植物的发育与在体情况基本相同,而人类未成熟睾丸组织异种移植物的发育与正常生理状态相比较呈现出加速的倾向。