Histological and immunocytochemical study of deferens ducts in the Chinese rat snake (Zaocys dhumnades)

To investigate the relationship between structure and function of the deferens ducts in the Chinese rat snake （Zaocys dhumnades）, morphological changes within an annual cycle were observed by routine histological techniques. Also, the correlation of androgen receptor （AR）, estrogen receptor （ER）, progesterone receptor （PR） and aromatase （Ar） expressions in the vas deferens and testis were studied immunohistochemically. To confh＇m that the sperm and the spherical structure existed in deferens ducts, we also used routine histological technique observed deferens ducts in the Striped-tailed rat-snake （Elaphe taeniura）, Red-banded snake （Dinodon rufozonatum）, and Tiger-spotted neck- troughed snake （Rhabdophis tigrina lateralis）. The results showed that the deferens ducts of the Chinese Rat Snake were composed of efferent duct, epididymal duct and vas deferens. Efferent duct contained sperm from August-October, and the sperm were observed in the epididymal duct from August-the following January. Throughout the year （except July） a large number of sperm were present in the vas deferens where a previously unreported spherical structure formed by spermatids was observed, which showed no significant differences in the IOD values of AR-, ER-, PR- and Ar- immunoreactivities. Since the spermatids in the spherical structure were undergoing spermatogenesis and this phenomenon also existed in the Striped-tailed rat-snake and Red-banded snake, the term, seminiferous spherule, was named for this spherical structure This study demonstrated that the testis was the main site for snake spermiogenesis, and the seminiferous spherule in vas deferens was the other Both the epididymis and vas deferens stored sperm; however, the vas deferens was the main organ for sperm storage.

Morphological Characteristics of Smooth Muscle Cells Isolated from the Rat Ductus Deferens

The aim of this study was to establish a method of isolating and culturing smooth muscle cells from the ductus deferens of rats. Smooth muscle cells were prepared from ductus deferens by explanting technique after dissection of adventitia and intimae, and cultured in vitro. The identification of the smooth muscle cells were verified by using anti u-smooth muscle actin （a-SMA） immunohistochemistry studies. The result suggested that the cells are multi-morphous, showing long fusiform or star shapes. The apophysis of cells contacted and coalesced to each other, in some regions the cells overlapped in multilayer, while in the other regions they formed monolayer that fluctuated and showed a ＂peak-valley＂ shape. They presented a positive reaction through immunohistochemistry studies. The purity of the cells was more than 99% through this method. The culturing of smooth muscle cells by explanting technique is simple and stable.

The CFTR polymorphisms poly-T, TG-repeats and M470V in Chinese males with congenital bilateral absence of the vas deferens

Congenital bilateral absence of the vas deferens （CBAVD） is a frequent cause of obstructive azoospermia, and mutations of the cystic fibrosis transmembrane conductance regulator （CFTR） gene have also been frequently identified in patients with CBAVD. However, the distribution of the CFTR polymorphisms M470V, poly-T, TG-repeats and F508del mutation in the Chinese CBAVD population with presumed low cystic fibrosis （CF） frequency remains to be evaluated. Samples obtained from 109 Chinese infertile males with CBAVD and 104 normal controls were analyzed for the presence of CFTR （TG）m（T）n, M470V and F508del by PCR amplification followed by direct sequencing. Our study showed that the F5OSdel mutation was not found in our patients. The 5T mutation was present with high frequency in Chinese CBAVD patients and IVS8-5T linked to either 12 or 13 TG repeats was highly prevalent among CBAVD patients （97.22% of 72 cases and 96.91% of 97 alleles with IVS8-5T）. Moreover, a statistically significant relationship between TG 12-5T-V470 haplotype and CBAVD was detected. This study indicated that the CFTR polymorphisms poly-T, TG-repeats and M470V might affect the process of CBAVD in the Chinese population.

Vas deferens, a site of male contraception: an overview

The vas deferens is a site which can be exploited for male contraception without undue side effects. The only ef-fective technique available for male contraception is vasectomy, being practiced world wide, despite that it is a perma-nent surgical procedure and its successful reversal is not assured. Although no-scalpel vasectomy minimizes surgicalprocedures, the fate of its reversal is akin to that of vasectomy. Several occlusive and non-occlusive vasal procedureswhich claim to be reversible without surgical intervention, possess more disadvantages than advantages. Vas occlusionwith plug, ' Shug' or medical grade silicone rubber, although claimed to produce reversible azoospermia without affect-ing spermatogenesis, requires skilled microsurgery for their implantation and later removal. RISUG^R, a non-scleroticpolymer styrene maleic anhydride (SMA), could be more advantageous than vasectomy and other vas occlusive proce-dures in that it could be a totally non-invasive procedure by 'no-scalpel injection' and 'non-invasive reversal'. It isclaimed to offer long-term contraception without adverse side effects and also to be possible as a male spacing methodby repeated vas occlusion and non-invasive reversal. The drug is currently under multicentre Phase Ⅲ clinical trial.

Identification of the second CFTR mutation in patients with congenital bilateral absence of vas deferens undergoing ART protocols

Congenital bilateral absence of vas deferens （CBAVD） is a manifestation of the mildest form of cystic fibrosis （CF） and is characterized by obstructive azoospermia in otherwise healthy patients. Owing to the availability of assisted reproductive technology, CBAVD patients can father children. These fathers are at risk of transmitting a mutated allele of the CF transmembrane conductance regulator （CFTR） gene, responsible for CF, to their offspring. The identification of mutations in both CFTR alleles in CBAVD patients is a crucial requirement for calculating the risk of producing a child with full-blown CF if the female partner is a healthy CF carrier. However, in the majority of CBAVD patients, conventional mutation screening is not able to detect mutations in both CFTR alleles, and this difficulty hampers the execution of correct genetic counselling. To obtain information about the most represented CFTR mutations in CBAVD patients, we analysed 23 CBAVD patients, 15 of whom had a single CFTR mutation after screening for 36 mutations and the 5T allele. The search for the second CFTR mutation in these cases was performed by using a triplex approach： （i） first, a reverse dot-blot analysis was performed to detect mutations with regional impact; （ii） next, multiple ligation-dependent probe amplification assays were conducted to search for large rearrangements; and （iii） finally, denaturing high-performance liquid chromatography was used to search for point mutations in the entire coding region. Using these approaches, the second CFTR mutation was detected in six patients, which increased the final detection rate to 60.8%.

Histological study of vas deferens following intravasallaser irradiation

<abstract>Aim: To study the histologic changes of the vas deferens following Nd: YAG laser irradiation. Methods: Intravasal laser irradiation was given to (i) 52 segments of rabbit (laser dosage: 2 seconds at 40 W-50 W) and 16 segments of human (3 seconds at 45 W-55 W) vas deferens in vitro, (ii) 25 rabbit vasa (2 seconds-2.5 seconds at 40 W-45 W) in vivo and (iii) 2 human vasa (3 seconds at 55W) in vivo. Segments of vasa were removed from the in vivo irradiated vasa deferentia 15 days-180 days (rabbit) or 15 days (man) after the exposure. All vas segments were embedded in methacrylate resin. Serial sections (thickness 25μm-30μm) were obtained and observed under a light microscope. Results: (i) Laser-induced damage reached the muscularis layer in 27 % and 94 % of the rabbit and human vas segments in vitro, respectively, (ii) Fourteen of the 25 in vivo rabbit vasa were completely occluded by fibrous tissue and the longer the time interval after treatment, the more likely was the vas occluded. Those unoccluded vasa had either a normal histology or a mucosal damage, (iii) One in vivo human vas was almost completely occluded by the fibrous tissue but the other had a relatively large lumen packed with sperm granulomatous tissue and partial destruction of the smooth muscle layer. Conclusion: Laser irradiation can induce long-term vas occlusion; for rapid occlusion, laser doses just completely destroying the mucosal layer will be advisable.

Morphological changes of spermatozoa in proximal vas deferens after vasectomy

Aim: To investigate the morphological changes of spermatozoa in the proximal vas deferens after vasectomy.Methods: Proximal vas deferens fluids were collected from 79 fertile men (group A) and 64 vasectomized men (groupB) during the operations of vasectomy or vasovasostomy. Sperm morphology in the proximal vas deferens wasanalyzed after staining with the modified Papanicolaou method. Results: The percentage of spermatozoa with anormal oval head from group B (50.7 % ± 21.7 % ) was significantly lower than that of group A (75.2 % ±11.1%). The data in group A was similar to those of normal semen and therefore represents the physiologicalcondition of the proximal vas deferens sperm of fertile men. There were no significant differences in the percentages ofnormal oval heads in group B with the time since vasectomy. Conclusion: After vasectomy, the spermatozoa in theproximal vas deferens and epididymis were continuously degenerating and being replenished by spermatozoa comingfrom testis. The obvious morphological degeneration occurred in the sperm tail and spermatozoa with a small oval headand amorphous heads were increased.

Early microrecanalization of vas deferens following biodegradable graft implantation in bilaterally vasectomized rats

We evaluated a biodegradable graft for reconstruction of rat vasa deferentia with long obstructed or missing segments. A total of 47 Sprague-Dawley rats underwent bilateral vasectomy and were divided into groups according to length of the vas deferens affected （0.5, 1, 1.5 cm）. After 8 weeks, poly-（D,L-lactide） （PDLA） grafts were used to reconnect the vas deferens, Grafts and adjoining vasa deferentia were excised 8 and 12 weeks later and evaluated microscopically. At 8 weeks, microscopic changes included a robust inflammatory response around the grafts. All grafts were still intact but in the early stages of degradation. No microtubules, indicative of vas deferens recanalization, were identified. One specimen showed evidence of healing and neovascularization at the interface zone between the vas deferens and the graft. At 12 weeks, grafts were further degraded but still present. Microscopic evaluation showed decreased inflammation. Seven specimens showed neovascularization at the interface zone; two of these showed distinct epithelialized vas deferens microcanals at the graft edges. One specimen showed a microcanal spanning the entire 0.5-cm graft. A time period of 8 weeks is not ample enough for vas deferens regeneration in the setting of a biodegradable PDLA graft; however, early evidence of re-growth was seen at 12 weeks. A longer healing time should permit further biodegradation of the graft, as well as re-growth and possible eventual reconnection of the vas deferens, allowing passage of sperm. These findings suggest a potential role for biodegradable grafts in the reconstruction ofvas deferens with long obstructed segments.

Micro-recanalization in a biodegradable graft for reconstruction of the vas deferens is enhanced by sildenafil citrate

This study investigated the effect of sildenafil citrate on micro-recanalization and neovascularization, which were previously demonstrated in a rat model using biodegradable grafts （BGs） for vas deferens reconstruction. A total of 24 male rats underwent bilateral vasectomy with removal of a 0.5-cm vasal segment and were randomly assigned to four groups. Groups 1 and 2 underwent immediate vasovasostomy. Groups 3 and 4 underwent interposition of a 0.5-cm BG in the vasal gap. Groups 1 and 3 were given 5 mg kg-1 day-1 oral sildenafil. Other groups were given placebo. Rats were housed with females 12 weeks postoperatively. Reconstructed vasal segments were harvested 16 weeks postoperatively and analyzed histologically. Fluid from the distal vasal stump was analyzed for motile sperm. Urine samples obtained 16 weeks postoperatively were analyzed for cGMP levels. cGMP levels in rats treated with sildenafil were signifcantly higher than in control rats. No pregnancies were sired by grafted groups. In all, 5/6 rats in group 1 and 3/6 rats in group 2 sired litters. No motile sperm were noted in the vasal fluid of the grafted groups. Motile sperm were noted in all rats in group 1 and in 5/6 rats in group 2. In addition, 29 and 4 microcanals were detected in the sildenafil and placebo groups, respectively （P = 0.023）. No microcanal exceeded 3 mm in length. An average of 12 and 28 blood vessels per graft were noted in the placebo and sildenafil groups, respectively （P 〈 0.0001）. In conclusion, sildenafil enhances micro-recanalization and neovascularization in BG used for vas deferens reconstruction, but does not increase the microcanal length after 16 weeks.

Non-invasive reversal of intraluminal vas deferens polymer injection-induced azoospermia——technology

Aim: The rationale and technique underlying a novel concept of non-invasive removal of an intravasal vas deferens poly-meric contraceptive drug to reverse drag injection-induced azoospermia are explained. Thus the conventional methods ofsurgical exploration to remove vas deferens plugs and intravasal injection of solvents to flush out contraceptive drugs are tobe replaced by steps which will be readily accepted by subjects. Methods: The approach is based upon the non-invasiveapplication of specific forces to various segments of the vas deferens so that non-sclerosing and non-tissue-adherent com-pounds, in particular styrene maleic anhydride (SMA) can be expelled. Forces are generated by palpation; percuta-neous electrical stimulation; vibration application; and percussion. The forces help to propel the intravasal polymer to-wards the ejaculatory duct for expulsion during ejaculation. All aspects of the total technique are clinically acceptable,simple, atraumatic, unlikely to cause pain and discomfort even without tranquilizers, local or general anaesthetics. Theprocedure may be repeated several times in different sittings spaced apart by about one week to achieve adequate plug ex-pulsion. Results: Model experiments demonstrated the feasibility of the concept. The polymer was nonadherent andcould be moved within the vas deferens by the application of specific forces. Sufficient removal was possible to enablespermatic fluid to be transported along a region previously occupied by the polymer. A corroborating subhuman primatestudy by an independent investigator has shown that the semen profile becomes normal following the reversal. Conclu-sion: Adoption of the new technique may provide a means of non surgical restoration of normal semen profile after a pe-riod of fertility control obtained by intravasal drag injection. (Asian J Androl 1999 Sep ; 1: 131 - 134)

Purinergic contraction of the rat vas deferens in L-NAME-induced hypertension：effect of sildenafil

Hypertension （HTN） is a risk factor for erectile dysfunction, but its effect on vas deferens （VD） contractility and the ejaculatory response has not been delineated. NG-nitro-L-arginine methyl ester （L-NAME）, a nitric oxide synthase inhibitor, was used for induction of nitric oxide （NO）-deficient HTN. Our aim was to evaluate the effects of L-NAME-induced HTN on rat VD contractility and to determine whether sildenafil affects VD contractility. A total of 36 male rats were divided into （1） control, （2）L-NAME-HTN, （3） sildenafil treated L-NAME-HTN groups. Group 2 was treated with L-NAME （40 mg kgI per day） in drinking water for 4 weeks. Group 3 received sildenafil （1.5 mg kg^-1 per day, by oral gavage） concomitantly with L-NAME. The prostatic portion of the VD was subjected to electrical field stimulation （EFS, 1-20 Hz）, and the P2X1 agonist α,β-methylene ATP （α,β meATP, 100 μmol L^-1-1 μmol L-1） and the al-adrenoceptor agonist phenylephrine （Phe, 100 μmol L^-1-1 mmol L^-1） were used to construct concentration-response curves. These experiments were repeated in the presence of P2X receptor antagonist, pyridoxalphosphate-6-azophenyl-2＇,4＇-disulfonic acid （PPADS, 30 μmol L-1）. VD contractions in response to EFS, a,β-meATP and Phe were significantly enhanced by L-NAME. Sildenafil treatment in the L-NAME group improved the contractile response of VD to EFS （20 Hz）. In the presence of PPADS, the enhanced contractile response of VD to EFS and a,β-meATP in hypertensive rats was reversed. In the rat model of chronic NO depletion, the purinergic and adrenergic components and EFS affect VD contractility. The VD contractile response may be mediated more by the purinergic system than the adrenergic system, and sildenafil may alter the ejaculatory response in men with PE.

An unusual mass arising from the vas deferens

An 18-year-old man presented with a history of fightsided abdominal pain and weight loss. Clinical examination revealed the presence of a right-sided abdominal mass arising from the pelvis. Baseline haematological and biochemical investigations were normal. A computerized tomography scan revealed a 78×56 mm cystic mass indenting the right posterolateral aspect of the bladder. The right kidney was absent with a congenital anomaly and duplication of the inferior vena cava below the left renal vein. A dimercaptosuccinic acid (DMSA) scan revealed

Loss-of-function CFTR p.G970D missense mutation might cause congenital bilateral absence of the vas deferens and be associated with impaired spermatogenesis

Congenital bilateral absence of the vas deferens(CBAVD)is observed in 1%–2%of males presenting with infertility and is clearly associated with cystic fibrosis transmembrane conductance regulator(CFTR)mutations.CFTR is one of the most well-known genes related to male fertility.The frequency of CFTR mutations or impaired CFTR expression is increased in men with nonobstructive azoospermia(NOA).CFTR mutations are highly polymorphic and have established ethnic specificity.Compared with F508Del in Caucasians,the p.G970D mutation is reported to be the most frequent CFTR mutation in Chinese patients with cystic fibrosis.However,whether p.G970D participates in male infertility remains unknown.Herein,a loss-of-function CFTR p.G970D missense mutation was identified in a patient with CBAVD and NOA.Subsequent retrospective analysis of 122 Chinese patients with CBAVD showed that the mutation is a common pathogenic mutation(4.1%,5/122),excluding polymorphic sites.Furthermore,we generated model cell lines derived from mouse testes harboring the homozygous Cftr p.G965D mutation equivalent to the CFTR variant in patients.The Cftr p.G965D mutation may be lethal in spermatogonial stem cells and spermatogonia and affect the proliferation of spermatocytes and Sertoli cells.In spermatocyte GC-2(spd)ts(GC2)Cftr p.G965D cells,RNA splicing variants were detected and CFTR expression decreased,which may contribute to the phenotypes associated with impaired spermatogenesis.Thus,this study indicated that the CFTR p.G970D missense mutation might be a pathogenic mutation for CBAVD in Chinese males and associated with impaired spermatogenesis by affecting the proliferation of germ cells.

Clinical features and microsurgical reconstruction of congenital unilateral absence of the vas deferens with obstructive azoospermia:a tertiary care center experience

Patients with congenital unilateral absence of the vas deferens(CUAVD)manifest diverse symptoms from normospermia to azoospermia.Treatment for CUAVD patients with obstructive azoospermia(OA)is complicated,and there is a lack of relevant reports.In this study,we describe the clinical features and evaluate the treatments and outcomes of CUAVD patients with OA.From December 2015 to December 2020,33 patients were diagnosed as CUAVD with OA in Shanghai General Hospital(Shanghai,China).Patient information,ultrasound findings,semen analysis,hormone profiles,and treatment information were collected,and the clinical outcomes were evaluated.Of 33 patients,29 patients were retrospectively analyzed.Vasoepididymostomy(VE)or cross VE was performed in 12 patients,the patency rate was 41.7%(5/12),and natural pregnancy was achieved in one of the patients.The other 17 patients underwent testicular sperm extraction as the distal vas deferens(contralateral side)was obstructed.These findings showed that VE or cross VE remains an alternative treatment for CUAVD patients with OA,even with a relatively low rate of patency and natural pregnancy.

High ligation of the hernia sac in open nonmesh inguinal herniorrhaphy is an important cause of iatrogenic vas deferens injury

Vasectomy damage is a common complication of open nonmesh hernia repair.This study was a retrospective analysis of the characteristics and possible causes of vas deferens injuries in patients exhibiting unilateral or bilateral vasal obstruction caused by open nonmesh inguinal herniorrhaphy.The site of the obstructed vas deferens was intraoperatively confirmed.Data,surgical methods,and patient outcomes were examined.The Anderson–Darling test was applied to test for Gaussian distribution of data.Fisher’s exact test or Mann–Whitney U test and unpaired t-test were used for statistical analyses.The mean age at operation was 7.23(standard deviation[s.d.]:2.09)years and the mean obstructive interval was 17.72(s.d.:2.73)years.Crossed(n=1)and inguinal(n=42)vasovasostomies were performed.The overall patency rate was 85.3%(29/34).Among the 43 enrolled patients(mean age:24.95[s.d.:2.20]years),73 sides of their inguinal regions were explored.The disconnected end of the vas deferens was found in the internal ring on 54 sides(74.0%),was found in the inguinal canal on 16 sides(21.9%),and was found in the pelvic cavity on 3 sides(4.1%).Location of the vas deferens injury did not significantly differ according to age at the time of hernia surgery(≥12 years or<12 years)or obstructive interval(≥15 years or<15 years).These results underscore that high ligation of the hernial sac warrants extra caution by surgeons during open nonmesh inguinal herniorrhaphy.

Sperm retrieval and intracytoplasmic sperm injection outcomes in men with cystic fibrosis disease versus congenital bilateral absence of the vas deferens

Recent data suggest that cystic fibrosis transmembrane conductance regulator(CFTR)gene alterations negatively impact male fertility beyond obstruction.We sought to compare gene alterations,sperm retrieval rates,and intracytoplasmic sperm injection(ICSI)outcomes among men with cystic fibrosis(CF)disease and congenital bilateral absence of the vas deferens(CBAVD)only.We retrospectively evaluated all men who underwent surgical sperm retrieval at two academic,high-volume andrology centers from 2010 to 2018.Only men with documented CFTR alterations and obstructive azoospermia from either CBAVD or CF were included.Differences between groups for CFTR abnormality,sperm retrieval,and ICSI outcomes were statistically analyzed.Overall,39 patients were included with 10 in the CF and 29 in the CBAVD groups.Surgical sperm retrieval rates were significantly lower in the CF group for sperm concentration(14.8×10^(6)ml^(-1)vs 61.4×10^(6)ml^(−1),P=0.02)and total motile sperm count(2.9 million vs 11.4 million,P=0.01).This difference was only predicted by homozygous delta F508 CFTR mutations(P<0.05).The CF group also demonstrated a significantly higher rate of rescue testicular sperm extraction(70.0%vs 27.6%,P<0.03)and lower fertilization rate with ICSI(32.5%vs 68.9%,P<0.01).In conclusion,those with CF demonstrated lower sperm quality,greater difficulty with sperm retrieval,and worse ICSI outcomes compared with CBAVD-only patients.Homozygous delta F508 CFTR mutations appear to significantly impair spermatogenesis and sperm function.

CFTR mutations causing congenital unilateral absence of the vas deferens(CUAVD)and congenital absence of the uterus(CAU)in a consanguineous family

Cystic fibrosis(CF)is one of the most common recessive genetic diseases,with a wide spectrum of phenotypes,ranging from infertility to severe pulmonary disease.Mutations in the cystic fibrosis transmembrane conductance regulator(CFTR)gene are considered the main genetic cause for CF.In this study,we recruited a consanguineous Iranian pedigree with four male patients diagnosed with congenital unilateral absence of the vas deferens(CUAVD),and one female patient diagnosed with congenital absence of the uterus(CAU).Testicular biopsy of one patient was performed,and hematoxylin and eosin(H and E)staining of testis sections displayed the presence of germ cell types ranging from spermatogonia to mature spermatids,indicating obstructive azoospermia.To explore the underlying genetic factor in this familial disorder,we therefore performed whole-exome sequencing(WES)on all available family members.WES data filtration and CFTR haplotype analysis identified compound heterozygous mutations in CFTR among four patients(two CUAVD patients carried p.H949Y and p.L997F,and one CUAVD and the female CAU patient carried p.H949Y and p.I148T).All these mutations were predicted to be deleterious by at least half of the prediction software programs and were confirmed by Sanger sequencing.Our study reported that CFTR compound heterozygous mutations in a consanguineous Iranian family cause infertility in both sexes.

Evaluation of the azoospermic male

When presented with an azoospermic patient, a thorough history and careful, considered physical examination often leads to a definite or presumptive diagnosis. An algorithmic, logical thought process is important to have in mind when embarking on the evaluation. Adjunctive laboratory tests, such as hormonal assays or genetic studies, are often complementary and/or additive and allow a very precise determination to be made as to the etiologies, either genetic or acquired. It is only with this information that a therapeutic plan can be made for the patient. As will be discussed, a targeted approach to testing is far more satisfying and cost-effective than a blind, shotgun approach.

Congenital agenesis of seminal vesicle

Congenital agenesis of the seminal vesicle （CASV） is frequently associated with congenital absence of the vas deferens （CAVD） or ipsilateral congenital vasoureteral communication. We reported two cases of a rare condition that the vas deferens open ectopically into Mullerian duct cyst associated with agenesis of the ipsilateral seminal vesicle. The diagnosis was confirmed by vasography. Transurethral unroofing of the Mullerian duct cyst was performed in both patients with favourable results, however, assisted reproductive technology （ART） was still necessary for them to father children.

Biophysical mechanism-mediated time-dependent effect on sperm of human and monkey vas implanted polyelectrolyte contraceptive

Aim： To determine the short and long-term morphological effects on sperm as induced by intra-vas alteration of pH and electrical charge. Methods： Desired biophysical influences were obtained by injection of reversible inhibition of sperm under guidance （RISUG） into the lumen of the vas deferens of human subjects and the monkey. RISUG is a polyelectrolyte hydrogel complex of styrene maleic anhydride （SMA） and dimethyl sulfoxide （DMSO） which generates an electrostatic charge and also lowers in a near space of pH domain. The morphology of sperm was examined by light microscopy, scanning and transmission electron microscopy. Human study enabled semen collection by masturbation as early as 3 h after injection and studies extended up to 6 months, in the monkey, on vas excision after RISUG implantation, sperm characteristics were examined in serial sections. Results： Semenology in clinical studies and histological data of the monkey showed a time-sequenced sperm plasma membrane, tail mitochondria and nuclear decondensation alterations in sperm structural components, which beared marked similarity to changes in the sperm head and tail during capacitation and entry into the ovum. Conclusion： The findings provide a means of causing such changes in the sperm that inhibit the fertilizing ability before the nucleus is affected. Therefore achieving non-obstructive vas-based contraception, without genotoxic or teratogenic effects caused by infertile sperm passing into the semen, is feasible.