Effects of long- and short-term vasectomy on structural and functional parameters of the rat

Apoptosis in testicular tissue of rats after vasectomy: evaluation of eNOS, iNOS immunoreactivities and the effects of ozone therapy

OBJECTIVE

We aimed to investigate the changes in endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) expression and apoptotic index in rat testicular tissue, as well as serum and seminal plasma sex hormone levels after vasectomy, and the effect of ozone therapy (OT).

MATERIAL AND METHODS

Adult male Wistar rats were used (n=6 per group). Control (G1), sham for 4 weeks (G2) or 6 weeks (G3), orchiectomy at the 4(th) (G4) or 6(th) (G5) week after left vasectomy, orchiectomy at the 4(th) (G6) or 6(th) (G7) week after bilateral vasectomy, orchiectomy after 6 weeks OT following left (G8) or bilateral (G9) vasectomy, orchiectomy after 6 weeks OT (G10).

RESULTS

In the left testes, while there were increases in eNOS and iNOS immunoreactivity and apoptotic indexes in G4 and G5, no changes were observed in contralateral testis. These values increased in G6 and G7, while OT inhibited these parameters in the left testis of G8 and both testes of G9. Sex hormone levels did not show any changes after vasectomy and ozone therapy.

CONCLUSION

While OT was found to be protective against some parameters mentioned above under stress conditions, it seemed to cause some harmful effects when used in healthy conditions.

The blood-epididymis barrier and inflammation

The blood-epididymis barrier (BEB) is a critical structure for male fertility. It enables the development of a specific luminal environment that allows spermatozoa to acquire both the ability to swim and fertilize an ovum. The presence of tight junctions and specific cellular transporters can regulate the composition of the epididymal lumen to favor proper sperm maturation. The BEB is also at the interface between the immune system and sperm. Not only does the BEB protect maturing spermatozoa from the immune system, it is also influenced by cytokines released during inflammation, which can result in the loss of barrier function. Such a loss is associated with an immune response, decreased sperm functions, and appears to be a contributing factor to post-testicular male infertility. Alterations in the BEB may be responsible for the formation of inflammatory conditions such as sperm granulomas. The present review summarizes current knowledge on the morphological, physiological and pathological components associated with the BEB, the role of immune function on the regulation of the BEB, and how disturbance of these factors can result in inflammatory lesions of the epididymis.

The effect of unilateral vasectomy on testosterone and testicular parameters in the adult male African giant rat (Cricetomys gambianus)

BACKGROUND

The effects of vasectomy on spermatogenesis and reproductive parameters are recognized to be specie-dependent with marked differences in levels of perturbations observed.

OBJECTIVES

To assess the impact of unilateral vasectomy on testosterone level and other testicular parameters in the male African giant rat (AGR) (Cricetomys gambianus).

METHODS

Sixteen adult male AGRs weighing 500-1300 g were recruited for the experiment. Animals were randomly divided into three experimental groups (1-3) and one control (sham operated) group with four rats per group. Experimental vasectomy was done by carefully ligating the vas deferens of the right testis of all the experimental groups (1, 2, and 3) and animals were allowed either 8, 6 and 2 weeks respectively before sacrifice. Sham-operated animals served as the control. Blood samples were collected and assayed for testosterone while testicular tissue was further processed for seminal fluid and histo-pathological analyses.

RESULTS

Spermatogenic parameters indicate a pattern of decline in sperm count and motility between the experimental groups and the control and azoospermia in the eight-week group. Histological alterations were marked by atrophy of seminiferous tubules which was proportional to the duration of vasectomy. Serum testosterone levels were significantly reduced at eight weeks. There was no statistically significant difference between sperm counts of right and left testes except for group 3. Results suggest that unilateral vasectomy of the AGR may have negative impact on the contralateral testis in the male African giant rat.

CONCLUSION

These preliminary results reveal that unilateral vasectomy in the AGR may result in perturbations of the histo-architecture of the testes with possible decline in function.

Epididymal obstruction results in isolated sperm heads in post-vasectomy rats

The aim of this study was to determine if, following vasectomy, epididymal obstruction resulted in changes in vasal stump fluid using a rat vasectomy model. One hundred and twenty-two mature male rats underwent bilateral surgical vasectomy and subsequent unilateral epididymal obstruction. Animals were randomly assigned to one of the five cohorts, which determined the time to kill and vasal fluid assessment. Numbers of whole sperm and sperm heads were compared between the obstructed and non-obstructed sides. Parametric analysis of microscopic vasal fluid findings was performed using a paired t-test. Whole sperm and sperm heads were detected bilaterally among the initial five cohorts. On the obstructed epididymis side, percentage of whole sperm dropped from 36.9% to less than 1% and sperm heads increased from 63.2 to 99.7% at 12 weeks post-obstruction (p < 0.05 at each time interval). On the unobstructed side, percentage of whole sperm rose from 66.3 to 89.5% and sperm heads dropped from 33.7 to 10.5% (p < 0.05 at each time interval). At 12 weeks, the difference between the obstructed and non-obstructed sides for both percentage and quantity of whole sperm and heads was significant with a p value of <0.001. In this rat model, following vasectomy and subsequent epididymal obstruction, testicular vasal stump fluid will contain progressively diminishing numbers of whole sperm and increases in the percentage and absolute numbers of sperm heads.

Effects of vasectomy on the epididymis

Common principles can be discerned in the response of the epididymis to vasectomy, despite species differences. Increases in the size and number of lysosomes are the most frequent changes in the epididymal epithelium. The presence or absence of additional alterations such as changes in the height of the epithelium may be related to variations in distensibility of the vas deferens and epididymis. Direct measurements by micropuncture of epididymal and seminiferous tubule hydrostatic pressure indicate that, contrary to dogma, increased pressure in the distal epididymis after vasectomy is not generally transmitted to the seminiferous tubules. The epididymal interstitium shows microscopic changes indicative of chronic inflammation, with infiltration of macrophages, lymphocytes, and plasma cells, and rats with these lesions have higher antisperm antibody levels than animals lacking epididymal changes. Macrophages and neutrophils may enter the duct through the epididymal epithelium, at sites of rupture of the duct, and in the efferent ductules. Cyst-like spermatic granulomas occur in virtually all species where the epididymis or vas deferens ruptures with escape of spermatozoa. The sites and timing of granuloma formation may depend on the mechanical properties of the tract in different species, and they are probably important in the immune response to vasectomy. Postvasectomy sera in Lewis rats recognize a consensus repertoire of dominant autoantigens that closely resembles the antigens bound by sera from rats immunized with isologous spermatozoa. There are multiple routes for disposal of the sperm that continue to be produced after vasectomy.

Effect of vasectomy on in situ pH in rat testis and epididymis

The effect of bilateral vasectomy on in situ pH in seminiferous tubules, initial segments, proximal caput, middle corpus and proximal cauda epididymides of the rat has been studied employing in vivo microelectrode techniques. After bilateral vasectomy of four weeks duration, a significant increase in acidity of luminal fluid in the initial segments of the caput epididymides was observed. By eight weeks post vasectomy, luminal pH in the initial segments was significantly more acid as compared to sham-operated control animals or four weeks vasectomy while, in contrast, luminal pH in the proximal cauda epididymides was significantly more alkaline. The alteration of luminal fluid pH in the initial segments and proximal cauda epididymides after bilateral vasectomy may be the result of impairment of acid-base, as well as water transport pathways.

Microrecanalization after vasectomy in man

Previously spermatozoa in the semen of vasectomized men were reported in 62 of 63 specimens from 24 men 2 to 31 years postvasectomy (Freund and Couture, 1982). A morphologic basis and term, "microrecanalization," was proposed for this observation. Serial sections (5 mu at 200-mu intervals) of 40 specimens removed at vasovasostomy from 20 men (2 to 14 years postvasectomy) were examined and microcanals (small epithelial-lined channels) were demonstrated in 27 specimens from 18 men. In nine of the 27 specimens, spermatozoa or sperm heads were found within the microcanals. Microcanals occurred in smooth muscle, connective tissue and scar tissue, in each segment, testicular, central and abdominal, in the presence or absence of the vas deferens. Microcanal continuity was traced for 200 to 1140 microns by computerized image analysis. Microrecanalization is characterized by the absence of inflammation or sperm extravasation and is histologically distinct from vasitis nodes or sperm granuloma. Microrecanalization provides morphologic and physiologic bases for the protection of the testis and maintenance of spermatogenesis in man after vasectomy.

Morphometric analyses of the epididymis from normal and vasectomized rats

To provide a structural basis for region-specific biochemical activities of rat epididymal cells and to assess the morphometric effects of vasectomy, tissue and cellular morphologic parameters for each of six histologically defined regions from the epididymis of long-term sham-operated and vasectomized rats were analyzed stereologically. In sham-operated rats, tubule diameter generally increased from region 1 to region 6 (163 microns to 338 microns) while tubular wall height decreased (35 microns to 17.5 microns) as did tubular wall volume density (0.48 to 0.12). For columnar epithelial cells, the absolute cell number/region ranged from 16.5 to 5.1 X 10(6) such that region 2 greater than region 1 greater than region 5 greater than region 4 greater than region 6 greater than region 3. Based on cell volume, the largest columnar epithelial cells were found in region 3 (2607 +/- 127 microns3). The epididymal tubule wall was made up of 91% columnar epithelial cells, 5% lymphocytes, and 4% basal cells. The relatively small tubular lumen, large wall volume, and large columnar epithelial cell number in the caput (regions 1 to 3) provide the structural basis for maximizing biochemical interactions between columnar epithelial cells and spermatozoa. In contrast, the distal cauda (region 6), with its large lumen and small tubular wall volume, is structurally optimized for the function of storage, which requires minimal columnar epithelial cell interaction with spermatozoa. In vasectomized rats, mean tissue volumes for most epididymal regions were significantly greater than in sham rats. The absolute number of lymphocytes in vasectomized rats significantly increased in several regions, thus implicating them in post-vasectomy events.

The incidence of spermatic granulomas and their relation to testis weight after vasectomy and vasovasostomy in Lewis rats

The occurrence of spermatic granulomas of the vas deferens was studied in Lewis rats at intervals up to 7 months after vasectomy or vasectomy followed 3 months later by vasovasostomy. The incidence of granuloma progressed with time to involve one or both tracts in 100% of vasectomized rats. In addition, the majority of animals developed new granulomas after vasovasostomy, even though fluid flow through the reconnected vas deferens was demonstrated in vitro. When individual tracts were analyzed, the weight of the testis was related to ipsilateral spermatic granuloma formation in both vasectomy and vasovasostomy groups at 3 and 4 months after initial operation. Testes were small in the absence of a granuloma but similar to those of sham-operated rats if a granuloma was present. The possible protective effect of spermatic granuloma formation on the testis is discussed.