Distribution of Zonula Occludens‐1 and Occludin and alterations of testicular morphology after in utero radiation and postnatal hyperthermia in rats

In utero irradiation (IR) and postnatal hyperthermia (HT) exposure cause infertility by decreasing spermatogenic colony growth and the number of sperm in rats. Four groups were used: (i) Control group, (ii) HT group (rats exposed to hyperthermia on the 10th postnatal day), (iii) IR group (rats exposed to IR on the 17th gestational day) and (iv) IR + HT group. Three and six months after the procedures testes were examined by light and electron microscopy. Some degenerated tubules in the HT group, many vacuoles in spermatogenic cells and degenerated tight junctions in the IR group, atrophic tubules and severe degeneration of tight junctions in the IR + HT group were observed. ZO‐1 and occludin immunoreactivity were decreased and disorganized in the HT and IR groups and absent in the IR + HT group. The increase in the number of apoptotic cells was accompanied by a time‐dependent decrease in haploid, diploid and tetraploid cells in all groups. Degenerative findings were severe after 6 months in all groups. The double‐hit model may represent a Sertoli cell only model of infertility due to a decrease in spermatogenic cell and alterated blood‐testis barrier proteins in rat.     

The influence of vasovasostomy on testicular alterations after vasectomy in Lewis rats

The occurrence of alterations in testicular weight and morphology after vasectomy and vasectomy reversal by vasovasostomy was studied in Lewis rats. Animals were studied 3, 4, and 7 months after bilateral vasectomy or a vasectomy followed 3 months later by vasovasostomy. Other rats served as sham-operated controls. The weights of the testes in vasectomy and vasovasostomy animals fell into two groups-small testes weighing less than 0.88 g and normal-sized testes of 1.2 g or more. When the extent of testicular alterations was estimated in sections for light microscopy by use of a semiquantitative testicular biopsy score count (TBSC), the morphology of the testes corresponded closely to the testis weight (r = .94), small testes having correspondingly low TBSC scores. In severely altered small testes, the seminiferous tubules were narrower than in sham-operated rats, and numbers of germ cells were greatly depleted. Many tubules contained only Sertoli cells and spermatogonia, although spermatocytes were present in a minority of tubules. A few seminiferous tubules contained multinucleate spermatids. Electron microscopy of severely altered tubules revealed closely apposed processes of Sertoli cells, which contained filaments, microtubules, and endoplasmic reticulum. In contrast, testes with normal weight in vasectomy and vasovasostomy groups resembled those of the sham-operated animals. Comparison of distributions of testicular biopsy score counts demonstrated differences between vasectomy and vasovasostomy groups as time after operation increased. At the 3-4-month intervals, approximately one-third of the testes were severely altered in both vasectomy and vasovasostomy groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

IL—1对输精管结扎大鼠睾丸间质细胞功能影响的体外研究

本文观察ＩＬ－１对正常和输精管结扎大鼠睾丸间质细胞（Ｌｅｙｄｉｇｃｅｌｌｓ，莱迪希细胞）细胞功能的影响，结果表明：在人绒毛膜促性腺激素（ｈｕｎａｎｃｈｏｒｉｏｍｉｃｇｏｎａｄｏｔｒｏｐｉｎｈＣＧ）的作用下，正常和输精管结扎大鼠睾丸Ｌｅｙｄｉｇ细胞培养上清中睾酮和ｃＡＭＰ的含量均明显高于相应的对照孔，且两组比较无明显差异，说明输精管结扎后睾丸Ｌｅｙｄｉｇ细胞对垂体激素的反应性并无改变，两组细胞受ＩＬ     

Early testicular changes after vasectomy and vasovasostomy in Lewis rats

The testes of Lewis rats were studied at intervals from 2 weeks to 3 months after bilateral vasectomy, vasectomy followed 1 month later by vasovasostomy, or sham operations. Aims were to determine the nature of early alterations after vasectomy, and to determine whether vasovasostomy after 1 month would result in reversal of vasectomy-induced changes. Approximately one-fourth of the testes in the vasectomy and vasovasostomy groups displayed histological changes, which consisted mainly of depletion of germ cells. The extent of the depletion varied greatly in different seminiferous tubules. In testes altered in this way, no abnormal infiltrations of lymphocytes, macrophages, or other cells were observed in the seminiferous epithelium or in the interstitium. The rete testis and straight tubules were normal in testes with altered seminiferous epithelium. A few testes in the vasectomy and vasovasostomy groups had necrotic centers. The results suggest that depletion of germ cells occurred as a result of shedding from the seminiferous epithelium into the lumen of the tubules. A cellular immune response, such as occurs in experimental allergic orchitis in other species, did not appear to be responsible for the observed loss of germ cells. This suggests a possible role for humoral antibody in this model, since there is an association between testicular changes and serum antisperm antibodies at longer intervals after vasectomy. Testicular alterations were not reversed by performance of a vasovasostomy 1 month after vasectomy.     

Quantitative (stereological) study of the effects of vasectomy on spermatogenesis in rabbits

Using stereological methods, especially the optical disector for unbiased estimation of nuclear number, our recent study demonstrated that long-term (6 or 12 months) vasectomy in the rhesus monkey had no significant effects on spermatogenesis (Peng et al. Reproduction 2002, 124, 847-856). This study aimed to determine the scenario in the rabbit using the same morphometric methodology. Three groups of normal male Japanese white rabbits (aged 4-5 months) were subjected to unilateral vasectomy; 10 days, 6 months and 12 months later both testes and epididymides were removed. Testicular and epididymal methacrylate-embedded sections were obtained for stereology. Vasectomy-induced damage to spermatogenesis was observed, primarily sloughing of spermatogenic cells with a greater reduction in the number of advanced (adluminal) cells. The damage was most severe at 10 days, occurring in all the testes on the vasectomized side and involving sloughing of even type A spermatogonia, the number of which returned to normal at 6 and 12 months. Damage was less severe at 6 and 12 months, being found in half of the testes of the vasectomy side, in which the total numbers of later germ cell types were 24.0-59.1% (spermatocytes) and 0.3-11.6% (spermatids) of control at 6 months, and 20.1-22.1% (spermatocytes) and 0.4-12.0% (spermatids) of control at 12 months. By contrast, Sertoli cell number per testis was unchanged following vasectomy in any group. Epididymis on the vasectomy side, especially at 10 days and 6 months, appeared larger than on the contralateral side, but this difference was not statistically significant, and no sperm granuloma was seen in the epididymis.     

Degenerated tubules in the guinea pig testis after long-term vasectomy or sham operation

The testes of eight unilaterally vasectomized and six sham-operated Dunkin Hartley guinea pigs were examined 3 years after operation by wax and resin histology and transmission electron microscopy. Degenerated tubules are reported that were common on the side of vasectomy but also found in the contralateral testes and in the controls. A central accumulation of macrophages, rich in phagocytosed debris including spermatozoal fragments, was surrounded by attenuated Sertoli cells, a markedly thickened basement membrane and myoid cells. At some sites macrophages impinged directly on the basement membrane. They probably represented highly degenerated seminiferous tubules. The study suggests that the response to injury of seminiferous tubules may show species variations. Macrophages did not feature in the degenerated seminiferous tubules we reported following vasectomy in the rat. However, the rat showed striking changes in the morphology of the basal laminae and myoid cells which did not occur in the guinea pig. Pathological changes have been reported in the human testis following vasectomy but their etiology is unclear. Studies in the guinea pig are enhancing understanding of the mechanisms and features of testicular damage.     

淋巴管阻断对大鼠睾丸生精上皮的影响

用外科手术的方法将正常成年ＳＤ大鼠双侧睾丸淋巴管阻断后，观察术后不同时间睾丸生精上皮的组织学变化。术后２天出现生精上皮的形态改变，生精细胞排列松散，部分精子细胞脱落，聚集在管腔部位。术后６天多数曲细精管的精子细胞全部脱落。假手术对照组，睾丸生精上皮具有正常的形态结构。     

Effects on the efferent ducts in Macaca mulatta.

Immunopathologic findings in efferent ducts of 36 rhesus macaques vasectomized as many as 12 years earlier and of 11 age-matched control animals were compared. Electron-microscopic observation of these ducts revealed changes after vasectomy. The epithelium shortened from a prevasectomy height of 25 mu to 14 mu as the ducts stretched after vasectomy. The number of sperm and macrophages in the lumen increased. The basement membrane was 300-700 A wide in nonvasectomized animals but several times that in animals vasectomized 6 or more years before; the mean width significantly increased with time after vasectomy. Numerous electron-dense immune complexes were found within the thickened lamina in 33% of vasectomized animals and in none of the controls. The mean size of the electron-dense areas varied from 0.01 sq mu in a monkey vasectomized 3 years earlier to 0.18 sq mu in an animal vasectomized 7 years earlier; the mean area significantly increased with time after vasectomy. Frozen sections of testis and epididymis were evaluated through the use of fluorescein-conjugated antibodies. Of the nonvasectomized controls, 18% showed immune deposits. Of the vasectomized animals, 53% revealed C3 deposition in the basement membrane surrounding the efferent ducts. The presence of electron-dense deposits plus the finding of putative immune complexes as revealed by immunofluorescence suggested that vasectomy enhances leakage of sperm antigens, particularly in the region of the efferent duct.     

Effect of long‐term vasectomy on seminiferous tubules in the guinea pig

The little previous work on the influence of vasectomy on the guinea pig testis has given controversial results. One group reports that the guinea pig suffers autoimmune orchitis while others claim damage may be mechanical. To clarify the issue, this study compares the morphology of seminiferous tubules 3 years after left unilateral vasectomy (8 guinea pigs) and control sham operation (6 animals). Grossly, left and right testes following left‐sided vasectomy were similar to controls and not significantly different in weight. On histology, left and right experimental testes and the control material showed various degrees of seminiferous tubular degeneration, including intraepithelial vesicle formation, loss of germ cells and intraluminal macrophages. Although vesicle formation was striking in most testes, quantitative analysis indicated that it was more frequent in the ipsilateral testis following unilateral vasectomy. It seems that vasectomy had exacerbated an age‐related phenomenon. Lymphocytic infiltration was seen in five of the left testes following vasectomy, in two of the corresponding right testes, but in none of the controls. Two vasectomized left testes, however, showed atrophic changes but no lymphocytic invasion. The results suggest that autoimmune orchitis follows vasectomy but that it may not be the primary cause of degeneration. Attempts to gain positive evidence for mechanical damage, however, were inconclusive. Clin. Anat. 12:250–263, 1999. © 1999 Wiley‐Liss, Inc.     

输精管结扎对大鼠睾丸、附睾及血清睾酮的中长期影响

目的：建立动物模型，观测输精管结扎中、长期对血清睾酮水平及睾丸和附睾的形态学影响，为评估输精管结扎术这一男性节育主要手段提供某些基础理论依据。方法：随机将40只4月龄Wistar大鼠，按4个等长的实验间期分为结扎组和对照组，在术后第4、6、8、10月时分别测定结扎组和对照组的血清睾酮(sT)浓度及其与雄激素结合蛋白(ABP)的结合率；在对受试动物的睾丸和附睾进行组织学定性观察的同时，用TAS-plus型自动图像分析仪，对睾丸切片进行了定量组织学测定。结果：除第4月实验组和对照组外，其他3个间期的实验组和对照组血清睾酮浓度均有显著变化；实验组睾丸和附睾均有无菌性炎症发生，且未随术后时间的延长而缓解。结论：结扎术对受试动物的中长期影响值得关注。     

Effects of vasectomy on spermatogenesis and fertility outcome after testicular sperm extraction combined with ICSI

BACKGROUND: Each year 40,000 men have a vasectomy in the UK whilst another 2400 request a reversal to begin a second family. Sperm can now be obtained by testicular biopsy and subsequently used in assisted conception with ICSI. The study aims were to compare sperm yields of men post-vasectomy or with obstructive azoospermia (OA) of unknown aetiology with yields of fertile men and to assess any alteration in the clinical pregnancy rates after ICSI. METHODS: Testicular tissue was obtained by Trucut needle from men who had undergone a vasectomy >5 years previously or had OA from other causes and from fertile men during vasectomy. Seminiferous tubules were milked to measure sperm yields. Numbers of Sertoli cells and spermatids and thickness of the seminiferous tubule walls were assessed using quantitative computerized analysis. RESULTS and CONCLUSIONS: Sperm yields/g testis were significantly decreased in men post-vasectomy and in men with OA, relative to fertile men. Significant reductions were also observed in early (40%) and mature (29%) spermatid numbers and an increase of 31% was seen in the seminiferous tubule wall (basal membrane and collagen thickness) of vasectomized men compared with fertile men. Clinical pregnancy rates in couples who had had a vasectomy were also significantly reduced.     

Spermatogenesis in the vasectomized monkey: Quantitative analysis

The seminiferous epithelium in mature vasectomized Macaca fascicularis was examined quantitatively to assess spermatogenesis. Monkeys were bilaterally vasectomized and controls were bilaterally sham operated. At postoperative periods of 10 and 18 months, groups of monkeys were castrated and their testes prepared for morphologic analysis. Diameters were measured in 100 cross sections of seminiferous tubules from each animal. Numbers of spermatogonia (Ad and Ap), preleptotene spermatocytes, pachytene spermatocytes, and step 7 spermatids, relative to Sertoli cell nucleoli, were counted in stage VII tubules. Tubule diameter and germ cell numbers per Sertoli cell nucleoli were not altered by vasectomy. Our study demonstrates quantitatively that spermatogenesis in the monkey is not inhibited up to 18 months following vasectomy.     

Relationship between time period after vasectomy and the reproductive capacity of sperm obtained by epididymal aspiration

BACKGROUND: It is not well defined whether the elapsed time after vasectomy has any influence on the outcome of IVF-ICSI using epididymal sperm. We analysed retrospectively the results of 151 ICSI cycles in which sperm of vasectomized men were used at different time periods after vasectomy. METHODS: Oocytes were obtained after a desensitizing ovarian stimulation protocol using GnRH agonist in association with recombinant FSH and HCG. Sperm were retrieved by percutaneous epididymal sperm aspiration. The cycles were split into three groups: < or =10 years after vasectomy (group 1, n = 47), 11-19 years after vasectomy (group 2, n = 79), and > or =20 years after vasectomy (group 3, n = 25). RESULTS: As might be expected, the mean age of men differed in the three groups (group 3 > group 2 > group 1), and the mean age of the women was also significantly higher in group 3 than in groups 1 and 2, although no differences were described between groups 2 and 3. All other laboratory and clinical parameters were similar in the three groups. Ongoing pregnancy and implantation rates (34, 25, 8% and 22, 15, 6% respectively) decreased significantly from group 1 to group 3. CONCLUSION: Pregnancy and implantation rates after ICSI with sperm from vasectomized men are negatively correlated with the time interval from vasectomy, which cannot be explained purely by male or female ageing.     

不同阶段生精小管组织学结构研究

目的探讨不同阶段人体睾丸生精小管面积、生精小管管腔面积变化和生精上皮在不同阶段的组织学特点,及其与生殖的关系。方法:应用常规组织制片技术和图像分析技术。结果①生精小管平均面积变化,从胚胎睾丸形成到青春期前,随睾丸逐渐发育增大,睾丸间质增多,但生精小管面积无明显增大;自青春期生精小管面积迅速增大,25岁左右达到峰值,45岁左右生精小管平均面积缓慢减少,55岁以后显著减少。②生精小管管腔面积变化,从胚胎睾丸形成到青春期前,生精小管几乎无管腔;青春期管腔开始出现并迅速增大,20岁左右达到峰值;于45岁左右管腔面积缓慢减少,55岁以后显著减少。③生精小管的组织学结构变化,从胚胎睾丸形成到青春期前,生精小管上皮由精原细胞和支持细胞组成,但随睾丸发育增大,睾丸间质增多,生精小管上皮和基膜间渐出现明显的间隙;青春期开始,生精小管上皮发育,生精细胞层数增加,管壁各级生精细胞典型,腔面可见精子;55岁后睾丸纤维化明显,生精小管皱缩,随年龄增长,生精上皮细胞数量渐减少,排列紊乱,基膜增厚。结论①生精细胞增殖旺盛是生精小管平均面积迅速增大的原因之一;生精细胞增殖旺盛的阶段是20～30岁,最佳时期是25岁左右。②生精小管管腔的出现与生精细胞的凋亡、基膜扩大的速率远远大于生精细胞的增殖水平有关,而生精小管管腔的出现有利于精子的生成与运输。③衰老睾丸生殖功能的下降与其组织结构的纤维化及生精小管基膜厚度增加等因素有关。     

吸入高浓度氢气增强四氯化碳损伤性大鼠生精细胞核糖体蛋白S6激酶的表达

目的探讨吸入3%氢气对四氯化碳(CCl4)损伤性大鼠生精细胞核糖体蛋白S6激酶(p70s6k)表达及其增殖功能的影响。方法将18只健康雄性SD大鼠随机分成对照组、CCl4组和氢气治疗组。对照组每周一、四背部皮下注射橄榄油(0.12ml/100g),CCl4组和氢气组每周一、周四皮下注射体积分数60%的CCl4-橄榄油(0.3ml/100g),连续4周。氢气组自实验的第22天吸入3%氢气,1h/d,连续7d。取右侧睾丸和附睾,行石蜡包埋切片,苏木素伊红染色和免疫组织化学染色。取左侧睾丸组织,行Western blotting检测。结果对照组睾丸生精小管内可见多层生精细胞,排列有续,结构完整。CCl4组睾丸生精小管细胞层数减少,结构紊乱,附睾管柱状上皮变薄;氢气组生精细胞数量和附睾管高柱状上皮细胞明显改善。CCl4组大鼠附睾精子密度较对照组降低,氢气组的精子密度明显高于CCl4组(t=4.91,P0.05)。免疫组织化学染色显示,氢气组生精细胞质中p70s6k(t=7.63,P0.05)和PCNA(t=20.08,P0.05)的表达明显强于CCl4组。Western blotting检测显示,氢气组睾丸组织中p70s6k的表达与CCl4组相比明显增强(t=3.64,P0.05)。结论吸入高浓度氢气能明显增强CCl4损伤性大鼠睾丸生精细胞p70s6k的表达,改善CCl4损伤引起的的生精细胞的增殖功能。     

新生小鼠睾丸组织移植到裸鼠体内不同时期移植物的组织学观察

目的 通过测量不同发育时期移植物的重量及观察其中生精小管结构和生精细胞组成情况,对去势雄性小鼠中移植的新生小鼠睾丸组织生长和发育进行系统观察.方法 将出生1～2d昆明小鼠睾丸移植到7～12周去势雄性免疫缺陷小鼠背部;在移植后不同时间段 (分为3d、1～11周和3～6月16个组)取出移植物,计算移植物的回收率,测定移植物重量,观察移植物中生精小管结构及生精细胞的组成.结果 从移植的450个新生小鼠睾丸组织,回收到405个移植物,总回收率为90.0%.重量比移植前增加约40倍.移植物中生精小管的发育及各阶段生精细胞出现时间与在正常小鼠中所见基本相同.移植时间超过8周后,生精上皮的退化现象显著增加.结论 将新生小鼠睾丸组织异位移植到受体背部后的发育进程与在体情况相同,第1次生精波结束后的时间应为获取精子细胞和精子的最佳时间,大约是移植后5～7周.     

Testicular Biopsy Score Count After Vasectomy in Albino Rats

Context: One of the challenging problems faced by the entire world is population explosion. The vasectomy is simple, safe, quick and effective vital method of male sterilization. In the recent years a large number of vasectomies have been performed in India, since the inception of National Family Planning Program in 1956. Thus the number of request for the restoration of fertility is also increased. Aim: The present study was carried out to know whether the testicular biopsy score count, indicating the process of spermatogenesis remains normal after vasectomy. Material & Methods: The testicular biopsy count of testes of 50 male albino rats was studied one, two, three and four months after vasectomy, in 10 male albino rats of each case and 10 male albino rats served as control. Result: After vasectomy seminiferous tubules are cut in various planes covered externally by connective tissue stroma with normal microscopic picture. The spermatogonia, spermatocytes, spermatids, Sertoli cells and spermatozoa show normal structure with normal size blood vessels in interstitial connective tissue, in vasectomised and control rats. In some seminiferous tubules granular cytoplasmic vesicle like structures are seen filling the lumen and spermatids in metamorphosis phase to spermatozoa. Many round or elongated heads of spermatozoa are present at apical portion of Sertoli cells. The control rats as well as vasectomised rats at four after vasectomy have shown the testicular biopsy score count of nine (9) and ten (10) on TBSC of Johenson. Conclusion: On critical analysis it is concluded that the testicular biopsy score count remains normal at four months after vasectomy.     

Apurinic/apyrimidinic endonuclease immunoreactivity in germ cells of experimental varicocele-induced rat testes

Increased germ cell apoptosis is related to oxidative DNA damage; therefore, we investigated whether there was a significant change in apurinic/apyrimidinic endonuclease (APE) in varicoceles. Experimental varicoceles were created by partial ligation of the left renal vein of adult male Sprague-Dawley rats, which were sacrificed at 1, 3 and 6 weeks after varicocele creation. Testicular tissues were sampled for TUNEL, Western blotting and immunohistochemistry. There was a significant increase in apoptotic germ cells in the ipsilateral testes 6 weeks after varicocele creation. Increased activation of p53, Bax and cleaved caspase-3 in the left testes was also noted. APE increased activation until 3 weeks after varicocele creation, and then decreased at 6 weeks after varicocele surgery. The spermatocytes were immunostained for both 8-hydroxy-2′-deoxyguanosine and APE, but the spermatogonia revealed only APE immunopositivity in the defective tubules. These results suggest that repression of APE is an underlying mechanism of augmented p53-dependent apoptosis in varicocele-induced rat testes and that remaining APE in the spermatogonia plays a decisive role in regaining testicular spermatogenic function after varicocelectomy.     

高压氧治疗对2型糖尿病大鼠睾丸的保护作用及其机制

目的:研究高压氧对大鼠糖尿病睾丸病变的保护作用并探讨其机制.方法:32只大鼠,其中8只Wistar正常大鼠,24只2型糖尿病GK大鼠,分4组,分别为对照组、模型组、二甲双胍对照组及高压氧组.对照组和模型组予纯净水5 mL/(kg·d)灌胃,二甲双胍组予二甲双胍混悬液250 mL/(kg·d)灌胃,高压氧组予纯净水5 mL/(kg·d)灌胃,同时加以稳压纯氧0.15 MPa处理30 min.3周后集中处死,摘取睾丸组织.睾丸组织经甲醛溶液固定后制成切片,分别行HE染色观察组织结构变化;TUNEL法检测细胞凋亡情况,免疫组织化学法检测NOS及SOD蛋白表达水平.结果:对照组睾丸曲细精管HE染色后光镜下见丰富饱满,生精细胞5~6层,腔内见丝状精子;模型组睾丸曲细精管萎缩,生精细胞数量减少,只有2~3层,腔内精子减少;高压氧组睾丸结构破坏较模型组明显减轻,曲细精管内精子数量明显增多,结构较完整.睾丸的凋亡主要发生在生精细胞,模型组凋亡指数最高,与其他3组相比差异具有统计学意义(P<0.05);高压氧干预后凋亡细胞数较模型组减少,但仍高于对照组(P<0.05),与二甲双胍组类似.模型组NOS表达最强,对照组最弱,与其他3组比较差异均有统计学意义(P<0.05);高压氧组NOS表达介于对照组和模型组之间(P<0.05),与二甲双胍组类似.模型组SOD表达最弱,对照组最强,高压氧组介于两者之间,与两组比较差异均有统计学意义(P<0.05).结论:糖尿病时氧自由基增多,并引起凋亡增加是引起睾丸损伤的重要原因,高压氧可以促进SOD的合成,使其清除多余氧自由基,通过此机制可以抑制细胞过度凋亡,从而达到保护睾丸组织的目的.     

Changes in seminiferous tubules after vasectomy

The histologic, immunohistochemical, and ultrastructural changes in the seminiferous tubules (ST) of 17 healthy adult males who had been vasectomized between 1 1/2 and 5 years are reported. There was minimal spermatogenesis in 4 cases. 8 of the cases underwent electron microscopy examination and 4 showed evidence of minimal histological spermatogenesis. The ST showed a thickening of the basement membrane and heavy deposits of lipofuchsin in the Sertoli cells (SC) seen as lipid infiltration. The spermatogenic cells presented variable changes characterized by the disorientation of cells, maturation arrest, and premature sloughing. No immune complex deposits were seen. Of the 9 cases followed, pregnancy occurred in 2 following vas reanastomosis; a regenerative capacity of the ST was seen in 6 cases. The follow-up studies also show that the morphological alterations initially produced by the vasectomy have little affect on the appearance of spermatogenesis after vas reanastomosis. Thus, we see that the vasectomy exerts its major effect on the SC and that the damage to these cells alters the testicular environment. However, these changes are apparently reversible following vasovasostomy.