Spermatogenic Damage Research Articles

GENE TRANSFER TO MOUSE TESTES BY ELECTROPORATION AND ITS INFLUENCE ON SPERMATOGENESIS

We transferred the adventitious gene pCAGGS-lacZ to mouse testes with the use of a square-wave electroporator and investigated the efficiency of gene transfer (GT) and the influence of the procedure on testicular damage and spermatogenesis. Mice were divided into 5 groups: (1-2) injection of gene/phosphate-buffered saline (PBS) into the interstitial space followed by electroporation (EP), (3) EP alone, (4-5) injection of gene/PBS without EP. The presence of the lacZ gene was determined by X-gal (5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside) staining and the polymerase chain reaction (PCR). The influence of transfer on spermatogenesis was assessed by evaluating the seminiferous tubules according to the Johnsen score (JS). TdT-mediated dUTP-biotin nick end-labeling (TUNEL) staining was performed for the detection of apoptosis in the testes to evaluate the testicular damage caused by GT, and fertilization ability was assessed by mating male mice from each group with normal female mice at 1, 2, 4, 6, and 8 weeks after the procedure. LacZ expression was detected by X-gal staining and PCR for 4 weeks after GT in group 1. But in group 4, LacZ expression was not detected for all times. In groups 1 through 3, the JSs decreased gradually until 4 weeks and recovered at 6 and 8 weeks after GT. The JSs were significantly decreased at 4 weeks for groups 1 through 3 compared with groups 4 and 5. In groups 1 through 3, apoptotic cells were significantly more numerous at 1, 2, and 4 weeks after the procedure, and there were significant differences in their numbers between groups 1 through 3 and groups 4 and 5 until 4 weeks after the procedure. The number of offspring did not differ significantly between all groups. These results suggest that although spermatogenic damage caused by EP could present problems, GT by EP might be effective for transfecting germ cells or somatic cells and could be applicable for in vivo gene therapy for male infertility in the future.

Cross-platform gene expression signature of human spermatogenic failure reveals inflammatory-like response

The molecular basis of human testicular dysfunction is largely unknown. Global gene expression profiling of testicular biopsies might reveal an expression signature of spermatogenic failure in azoospermic men. Sixty-nine individual testicular biopsy samples were analysed on two microarray platforms; selected genes were validated by quantitative real-time PCR and immunohistochemistry. A minimum of 188 transcripts were significantly increased on both platforms. Their levels increased with the severity of spermatogenic damage and reached maximum levels in samples with Sertoli-cell-only appearance, pointing to genes expressed in somatic testicular cells. Over-represented functional annotation terms were steroid metabolism, innate defence and immune response, focal adhesion, antigen processing and presentation and mitogen-activated protein kinase K signalling pathway. For a considerable proportion of genes included in the expression signature, individual transcript levels were in keeping with the individual mast cell numbers of the biopsies. When tested on three disparate microarray data sets, the gene expression signature was able to clearly distinguish normal from defective spermatogenesis. More than 90% of biopsy samples clustered correctly into the corresponding category, emphasizing the robustness of our data. A gene expression signature of human spermatogenic failure was revealed which comprised well-studied examples of inflammation-related genes also increased in other pathologies, including autoimmune diseases.

Contaminación química ambiental y daño espermatogénico

Objectives The objective of the current review was to study the male reproductive damage caused by environmental chemical contamination, especially that due to agropesticides. Methods An experimental animal model in mice, intoxicated with organophosphorate compounds is presented. The Californian red earthworm ( Eisenia foetida) was analyzed as a bioindicator of chemical contamination through evaluation of the reproductive damage produced by organophoshorates. Results In both mice and earthworms spermatogenic damage was evidenced by a reduced sperm count, alterations in chromatin quality, and increased apoptosis of spermatogenic cells. These changes were partially reverted by adding melatonin to the treated cultures. Conclusions The changes elicited by intoxication with organophosphorates in mice suggest impaired fertility in the mid- and long-term. The changes verified in the earthworm were valid indicators of chemical ground pollution, thus pointing to this organism as an efficient biosentinel species. Given that melatonin decreased the damage, these alterations could mainly be due to an increase in reactive oxygen species caused by the toxic activity of the pesticide.

Role of cAMP-responsive element modulator-τ (CREMτ) in ipsilateral testicular injury after unilateral testicular torsion-detorsion

To investigate the role of cAMP-responsive element modulator-tau (CREMtau), an essential transcription factor for spermatogenesis, in ipsilateral testicular injury after unilateral testicular torsion-detorsion. Controlled experimental study using rats. Research laboratory. Twenty adult male Sprague-Dawley rats. Ten rats in the control group underwent a sham operation of the left testes. Ten rats in the torsion-detorsion group received 1 hour of left testicular torsion. Orchiectomy was performed on all rats 3 months after detorsion. Testicular spermatogenesis was evaluated by measuring testicular weight, mean seminiferous tubular diameter, number of germ cell layers, and mean testicular biopsy score. The expressions of CREMtau mRNA and protein in testes were detected by reverse transcription-polymerase chain reaction and Western blot, respectively. Unilateral testicular torsion-detorsion caused significant spermatogenic damage in the ipsilateral testes, including reductions in testicular weight, mean seminiferous tubular diameter, number of germ cell layers, and mean testicular biopsy score. In ipsilateral testes with spermatogenic damage, the expressions of CREMtau mRNA and protein were also significantly reduced. Reduction in testicular CREMtau expression may be one of the mechanisms responsible for impairment of spermatogenesis in ipsilateral testes after unilateral testicular torsion-detorsion.

Influence of the male on embryo quality

Early pregnancy failure or loss (EPL) represents a major source of wastage and inefficiency in livestock production systems. Although successful embryo development is dependent upon genetic and epigenetic contributions from both the male and female, potential adverse male affects on embryo quality and development are probably often underestimated. Of adverse male effects which have been identified, those associated with sperm and semen “quality” have been best characterized. In turn, although many factors can adversely impact semen quality, the mechanisms involved are relatively few. This presents opportunities for identifying biological markers for spermatogenic damage, as well as protective measures.

A Prostaglandin D2 system in the human testis

As shown recently, cyclooxygenase 2 (COX2), the inducible key enzyme for the prostaglandin (PG) biosynthetic pathway, is abundantly present in interstitial cells of testes of men suffering from different forms of impaired spermatogenesis and sub- or infertility, but it is absent in human testes with normal spermatogenesis. Although the spectrum of the downstream products of COX2 action in testis, namely PGs, and their effects are not known, our results show that Prostaglandin D2 (PGD2) likely plays a role. We describe (a) PGD2 synthetases, as well as receptors for PGD2 (DP) in testicular interstitial cells of men suffering from spermatogenic damage and infertility, and report that (b) PGD2 is produced by and can affect Leydig cells of an animal model, which expresses testicular COX2 and DP.

Testosterone production and spermatogenic damage induced by organophosphorate pesticides

Parathion is an organophosphorate pesticide amply used in agriculture. Many alterations induced by organophosphorate pesticides have been described, such as: cytogenetic alterations in germinal cells, oligozoospermia and teratozoospermia in the mouse. The effect of Parathion, both pure (PP) and commercial (PC), on mouse interstitial cell testosterone production was evaluated in vivo and in vitro. Male mice were intraperitoneally injected with a single dose of 1/3 LD50 of Parathion, both PP and PC. The animals were sacrificed at 1, 8 and 40 days post injection to evaluate the impact of disrupting testosterone production on spermatogonia, spermatocytes and elongated spermatids. The plasma testosterone was assayed by standard radioimmunoanalysis. The same method was used to assay testosterone in the culture medium of interstitial cells obtained from the control and Parathion treated animals at the same time intervals. Sperm count, sperm teratozoospermia and tubular blockage were analyzed for an appraisal of spermatogenesis. Increase in the teratozoospermia and tubular blockage was detected in the PP and PC group at 8 and 40 days post injection. Plasma testosterone levels drop significantly at 8 days and recovered slowly at 40 days only in PP animals as detected in vivo, implying interference of testicular steroidogenesis due to the toxicant. Recuperation of normality occurs at long time intervals. In conclusion, Parathion disturbs the synthesis of testosterone in mice affecting qualitatively the spermatogenesis

Gene Transfer to Mouse Testes by Electroporation and Its Influence on Spermatogenesis

We transferred the adventitious gene pCAGGS-lacZ to mouse testes with the use of a square-wave electroporator and investigated the efficiency of gene transfer (GT) and the influence of the procedure on testicular damage and spermatogenesis. Mice were divided into 5 groups: (1-2) injection of gene/phosphate-buffered saline (PBS) into the interstitial space followed by electroporation (EP), (3) EP alone, (4-5) injection of gene/PBS without EP. The presence of the lacZ gene was determined by X-gal (5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside) staining and the polymerase chain reaction (PCR). The influence of transfer on spermatogenesis was assessed by evaluating the seminiferous tubules according to the Johnsen score (JS). TdT-mediated dUTP-biotin nick end-labeling (TUNEL) staining was performed for the detection of apoptosis in the testes to evaluate the testicular damage caused by GT, and fertilization ability was assessed by mating male mice from each group with normal female mice at 1, 2, 4, 6, and 8 weeks after the procedure. LacZ expression was detected by X-gal staining and PCR for 4 weeks after GT in group 1. But in group 4, LacZ expression was not detected for all times. In groups 1 through 3, the JSs decreased gradually until 4 weeks and recovered at 6 and 8 weeks after GT. The JSs were significantly decreased at 4 weeks for groups 1 through 3 compared with groups 4 and 5. In groups 1 through 3, apoptotic cells were significantly more numerous at 1, 2, and 4 weeks after the procedure, and there were significant differences in their numbers between groups 1 through 3 and groups 4 and 5 until 4 weeks after the procedure. The number of offspring did not differ significantly between all groups. These results suggest that although spermatogenic damage caused by EP could present problems, GT by EP might be effective for transfecting germ cells or somatic cells and could be applicable for in vivo gene therapy for male infertility in the future.

Lepidium meyenii (Maca) reduces spermatogenic damage induced by a single dose of malathion in mice

To observe the effect of the aqueous extract of hypocotyls of the plant Lepidium meyenii (Maca) on spermatogenic damage induced by the organophosphate insecticide malathion in mice. Mice were treated with 80 mg/kg of malathion in the presence or absence of an aqueous extract of Maca, which was orally administered 7, 14 or 21 days after injection of the malathion. Stages of the seminiferous epithelium were assessed by transillumination on days 0, 7, 14 and 21. The administration of Maca increased significantly the length of stage VIII on days 7, 14 and 21 of treatment compared with the controls. An increase in the length of stage IX occurred on day 14 of treatment. Malathion affected spermatogenesis by reducing the lengths of stage IX on day 7, stages VII and IX-XI on day 14 and a recovery of stages IX-XII on day 21. The magnitude of alteration in the length of stage IX produced by malathion was significantly reduced by Maca on days 7 and 14. The length of stage VIII was increased when Maca was administered to mice treated with malathion. Assessment of the relative length of stages of the seminiferous epithelium showed that Maca treatment resulted in rapid recovery of the effect of malathion. Maca enhances spermatogenesis following spermatogenic damage caused by the organophosphorous pesticide.

Association of meiotic arrest with lack of BOULE protein expression in infertile men.

Spermatogenesis is a complex developmental process of mitotic and meiotic cell divisions that ultimately results in production of haploid spermatozoa. Recent studies in flies demonstrate that the BOULE gene encodes a key factor of meiosis in male germ cells, regulating the expression of twine, a cdc25 phosphatase, which promotes progression through meiosis. In this study, we investigated whether a common mechanism underlies the block of germ cell maturation observed in idiopathic and nonidiopathic azoospermic patients with meiotic arrest. We examined, by immunohistochemistry, BOULE and CDC25A phosphatase protein, the human homolog of twine, expression in 47 men with meiotic arrest, mixed atrophy, or normal spermatogenesis. The presence of genetic alterations within the BOULE gene was investigated by single-stranded conformation polymorphism. BOULE protein expression in men with complete spermatogenesis can be restricted to stages from leptotene up to stages of late spermatocytes, whereas CDC25A expression ranges from leptotene spermatocytes to elongating spermatids. Although spermatocytes were present in all testicular biopsies with meiotic arrest (28 testes), BOULE protein expression was completely lacking. In addition, in nearly all biopsies in which BOULE was absent, CDC25A was concomitantly lacking. However, no mutations or polymorphisms in the BOULE gene were identified, which could explain the lack of BOULE or CDC25A expression. These results indicate that a major group of infertile men with meiotic arrest lack BOULE protein and its putative target, CDC25A expression. The spermatogenic failure seems to arise from factor(s) upstream of BOULE, which are possibly involved in regulating transcription and/or translation of BOULE. Thus, the spermatogenic damage leading to meiotic arrest is independent of the etiology and indicates that BOULE is a possible fundamental mediator of meiotic transition in the human.

Expression of carcinoembryonic antigen-related cell adhesion molecule-1 (CEACAM1) in normal human Sertoli cells and its up-regulation in impaired spermatogenesis.

Carcinoembryonic antigen-related cell adhesion molecule-1 (CEACAM1) is usually expressed at the luminal surface of different epithelia and is up-regulated in endothelial cells during angiogenesis. Here, we demonstrate evidence of morphogenetic effects of CEACAM1 in spermatogenesis. CEACAM1 is detectable in normal testicular tissue and seminal fluid. It is present in the adluminal part of Sertoli cells extending only as far as the tight junctions between them. CEACAM1 immunostaining is significantly increased and extends to the basal part of Sertoli cells in the presence of carcinoma in situ. Also, in vitro-induced spermatogenetic disturbance leads to an enhanced CEACAM1 expression in Sertoli cells after 3 days of culture. Remarkably, seminiferous tubules containing exclusively Sertoli cells do not exhibit any CEACAM1 expression. CEACAM1 staining was absent in vascular endothelial cells of normal testicular tissue, but present in small blood vessels of seminomas. These data suggest that CEACAM1 expression in Sertoli cells depends on the presence of germ cells and plays a role in adhesive interactions between Sertoli and differentiating germ cells. Its up-regulation in Sertoli cells accompanying spermatogenic damage may contribute to reconstruction and maintenance of the tubular structure of seminiferous tubules. Additionally, CEACAM1 is apparently involved in the angiogenesis of germ cell tumours.

Effects of Adenovirus Mediated Gene Transfer to Mouse Testis In Vivo on Spermatogenesis and Next Generation

We directly injected DNA into mouse testes in vivo using an adenovirus vector to transfect testicular cells. We then analyzed the transfection efficiency, immunological problems and effects of gene transfer on spermatogenesis and the next generation. In this study we discuss the potential of gene therapy for male infertility. A replication incompetent human adenovirus serotype 5 contained 2 deletions (E1 and E3 deletions) and was constructed such that the transgene was driven by the chicken beta-actin promoter to promote over expression of the downstream target gene (Lac Z). This adenovirus vector or control solution was injected into the interstitial space (intratesticular injection) or seminiferous tubules (intratubular injection) of the mouse testis. We investigated beta-galactosidase gene expression by X-gal (5-bromo-4-chloro-3-indolyl-beta-d-galactopyranoside) staining, the effects of gene transfer on spermatogenesis by evaluating the frequency of apoptotic cells by the TUNEL method, the inflammatory response on testes by detecting CD4 and CD8 positive cells immunohistochemically, and interleukin (IL)-6 and IL-8 by immunoblot analysis, epididymides sperm motility and the reproductive response of each mouse 3, 7, 14 and 28 days after injection. Intratesticular injection of adenovirus vector resulted in strong transgene expression in Leydig cells. In contrast, intratubular injection resulted in strong expression in Sertoli cells. Transgene expression was not detected in germ cells by either method. The peak of beta-galactosidase activity was on day 7, ie 0.674 +/- 0.20 (intratesticular) and 0.534 +/- 0.22 U (intratubular), and it decreased with time thereafter. The apoptosis index on day 7 was significantly higher in adenovirus injected groups than in noninjected groups, ie 0.46 +/- 0.20 vs 0.10 +/- 0.11 (intratesticular) and 0.78 +/- 0.31 vs 0.24 +/- 0.10 (intratubular). Transfected animals showed a slight mononuclear inflammatory response in the testes composed of CD4 and CD8 positive cells. Adenovirus vector stimulation resulted in the induction of IL-6 and IL-8 secretion in the testis. These immune responses subsided after day 7. There were no significant differences in the percent of motile sperm or the rate of abnormal sperm between the groups on any day after injection. Reproductive ability remained almost normal even after adenovirus mediated gene transfer with no effect observed in offspring. Our results suggest that although slight spermatogenic damage and inflammatory response caused by these methods may present problems, adenovirus mediated gene transfer may be effective for transfecting testicular somatic cells and applicable for in vivo gene therapy for male infertility in the future.

A novel approach for the analysis of DAZ gene copy number in severely idiopathic infertile men.

The deleted-in-azoospermia (DAZ) gene family constitutes the major candidate for the AZFc (azoospermia factor c) phenotype of male infertility, being deleted in about 10% of azoospermic and severely oligozoospermic subjects. Four DAZ genes are arranged in two clusters in AZFc, and standard analysis by PCR cannot distinguish among the different copies. Therefore only deletions of the entire gene cluster can be identified. We developed a PCR amplification-restriction digestion assay able to distinguish from DAZ genes for single nucleotide variants. Then we applied this approach to screen a group of idiopathic infertile men in which the DAZ genes presence was previously assessed by standard PCR analysis. Two patients out of 25 showed deletion of two copies of DAZ (DAZI and 2), suggesting that this mutation was actually the cause of spermatogenic damage. This preliminary screening demonstrates that deletions of copies of DAZ genes may be often found in severely infertile men and it strengthens the role of this gene family in spermatogenesis. Furthermore, this simple method, being able to distinguish among the different DAZ copies, could be used to screen a larger number of patients and to perform a more accurate diagnosis.

GnRH analog, leuprorelin acetate, promotes regeneration of rat spermatogenesis after severe chemical damage.

Future fertility is a major concern for cancer patients who undergo intensive chemotherapy. There has been controversy about whether hormonal treatments may have protective effects against the severe spermatogenic damage caused by chemotherapy or irradiation. Recently, it has been proposed that gonadotrophin-releasing hormone (GnRH) analogs administered after testicular damage stimulate the recovery of spermatogenesis. In this study, we have investigated the effects of GnRH agonist, leuprorelin, on the damage to spermatogenesis induced by busulfan. Fisher rats were treated with busulfan, 25 mg/kg, intraperitoneally. The effects of subcutaneous injections of leuprorelin before or after treatment were evaluated histologically 18 weeks later. The percentage of 'recovered' seminiferous tubules was 27.7 +/- 12.6% in control rats without leuprorelin and 26.9 +/- 10.2% in rats with leuprorelin injected 4 weeks before busulfan. Rats in both groups showed poor recovery of spermatogenesis with an increase of intratesticular fluid. However, rats treated with leuprorelin three times (4 weeks apart) after busulfan showed an improvement of up to 56.5 +/- 12.0% (P < 0.05). A focal but massive necrotic lesion in the testis was observed only in this group of rats. The results demonstrated that leuprorelin administered after chemical testicular damage enhanced the recovery of spermatogenesis. At the same time, a possible significant side-effect of leuprorelin was noted.

CDY1 analysis in infertile patients with DAZ deletions.

The DAZ (deleted in azoospermia) gene family is considered the major AZFc ("azoospermia factor" c) candidate responsible for male infertility. However, other genes have been recently mapped to this region and they could contribute to the AZFc phenotype. In particular, the testis-specific CDY1 (chromadomain protein 1) gene has one copy within the DAZ cluster and another one at its distal end. Therefore, this gene could be associated with the spermatogenic damage observed in DAZ-deleted patients since at least one CDY1 copy is invariably absent in these patients. In this study, we investigated whether selected infertile patients affected by different testiculopathies caused by DAZ deletions retained CDY1 and if a genotype-phenotype relation could be demonstrated. We found 3 out of 17 patients with absence of both CDY1 copies, while 14 patients have only one CDY1 copy absent. Two out of the 3 patients with deletion of both copies of CDY1 were affected by severe hypospermatogenesis while one patient presented Sertoli cell-only syndrome. Therefore, there was no clear relation between genotype and phenotype, and the loss of the distal copy of CDY1 does not seem to worsen the phenotype of infertile patients with deletion of the DAZ gene cluster. However, a possible contribution of CDY1 in determining the spermatogenic alteration could not be excluded.

A study on the mechanism of the spermatogenic damage after vasectomy in rats

Vasectomy may result in damage to spermatogenesis. There are several explanations for this damage, including an increase of pressure in the seminiferous tubules and an autoimmune reaction. Recently, vasectomy has been reported to induce germ cell death by apoptosis. However, the exact mechanism of this vasectomy-induced germ cell apoptosis is unclear. To elucidate this mechanism, we designed a vasectomized rat model and examined the testiscular alterations and apoptotic degeneration biochemically and microhistopathologically. Particularly, we analyzed the expression of nitric oxide synthase (NOS) and nuclear factor kappa B (NF kappa B), which plays a critical role in the induction of the iNOS gene, in the testis after vasectomy to gain insight into the association between germ cell apoptosis and these factors. The testes of 40 Wistar rats (10-weeks old) were studied at 1, 2, 5 and 10 weeks after unilateral (left) vasectomy. Wistar rats weighting 290 to 310 g were divided into 2 groups and subjected to underwent either unilateral vasectomy or sham surgery under ether anesthesia. Bilateral testes were carefully observed biochemically and histopathologically. Apoptosis was detected by an in situ end-labeling technique (detection of cellular DNA fragmentation) and electron microscopy. Neuronal NOS (nNOS), endothelial NOS (eNOS) and inducible NOS (iNOS) protein was detected by Western blotting and immunohistochemical studies using each NOS monoclonal antibody. To confirm the co-localization of cellular DNA fragmentation in germ cells and each NOS, each set of consecutive testis sections (one stained for cellular DNA fragmentation and the others for each NOS) were examined. Expression of NF kappa B proteins was examined immunohistochemically using a NF kappa B p65 polyclonal antibody. At 5 and 10 weeks after vasectomy, the vasectomized left testis was significantly lighter than the unvasectomized right testis and sham-operated testis. At that time, the seminiferous tubules of vasectomized testes were highly damaged, presenting narrow tubular diameter, disorder of cellular arrangement, depletion of the germ cells, and local interstitial fibrosis. Vasectomized testes demonstrated a significantly increased number of apoptotic germ cells per cross-sectional area compared with sham-operated testes at 5 and 10 weeks after operation (p < 0.01). Electron microscopy revealed apoptotic germ cells each with a darkly stained nucleus. Western blotting and immunohistochemical studies demonstrated that iNOS proteins were more strongly expressed on vasectomized testes as time passed after vasectomy. Examination of consecutive sections from the vasectomized testis revealed that visibly apoptotic germ cells that exhibited positive staining for cellular DNA fragmentation were also intensely stained for eNOS and iNOS. NF kappa B p65 proteins were more strongly expressed in the nucleus of germ cells in the vasectomized testis than in the sham-operated testis. We found that vasectomy results in damage to spermatogenesis in adult rats, that may induce germ cell apoptosis, and that iNOS and NF kappa B may play a critical role in the germ cell apoptosis after vasectomy.

Deletion and expression analysis of AZFa genes on the human Y chromosome revealed a major role for DBY in male infertility.

Three distinct regions, designated AZFa, b and c from proximal to distal Yq, are required for normal spermato-genesis in humans. Deletions involving AZFa (deletion interval 5C/D) seem to occur less frequently in infertile men and to be associated with a more severe testicular phenotype, with almost complete absence of germ cells. AZFa contains three genes, named USP9Y, DBY and UTY, and presents high homology with the mouse Delta Sxr (b) interval, deletion of which causes a severe spermatogenic impairment. However, the specific role of these genes in human spermatogenesis is still unknown and it is not clear which of them is responsible for the AZFa phenotype. Here we describe a complete sequence map of the AZFa region, the genomic structure of AZFa genes and their deletion analysis in a large number of infertile men characterized by well-defined spermatogenic alterations. Both USP9Y and DBY may cause severe testiculopathies, but DBY appears to be the major AZFa candidate. DBY is frequently deleted in infertile patients and its absence produces severe spermatogenic damage leading to a significant reduction of germ cells or even to their complete absence. Expression analysis of AZFa genes and their X-homologues revealed ubiquitous expression for all of them except DBY; this gene produces a long transcript which is ubiquitously expressed in addition to a shorter transcript which is only expressed in the testis, suggesting a specific role for DBY in the spermatogenic process. This hypothesis is further supported by the high similarity of DBY to other DEAD box proteins belonging to the PL10 subclass.

Bacterial Lipopolysaccharide-Induced Inflammation Compromises Testicular Function at Multiple Levels in Vivo

While it is well known that serious illness and inflammation reduce male fertility, the mechanisms involved are poorly understood. In adult male rats, a single injection of lipopolysaccharide at doses that induced either mild or severe inflammation, caused a biphasic decline in Leydig cell testosterone production and gonadotropin responsiveness. In the high dose group only, serum LH levels also were reduced; however, intratesticular testosterone concentrations remained at a level adequate to support qualitatively normal spermatogenesis in both treatment groups. Testicular interstitial fluid formation also declined in a dose-dependent fashion after lipopolysaccharide treatment. In the high dose group only, these hormonal and vascular changes were accompanied by an increase in endothelial permeability, microhemorrhage, and inflammatory cells in the testis, followed by vacuolization of round spermatid nuclei, disruption of Sertoli-germ cell contacts at stages I–IV of the cycle of the seminiferous epithelium, and subsequently apoptosis of spermatocytes at stages II–V. These data indicate that mild inflammation causes local inhibition of Leydig cell function with relatively little spermatogenic damage. The pathological changes in spermatogenic function during severe inflammation are most likely due to direct effects of inflammatory mediators on the seminiferous epithelium or testicular vasculature, rather than inhibition of the brain-pituitary-Leydig cell axis.

Bacterial Lipopolysaccharide-Induced Inflammation Compromises Testicular Function at Multiple Levelsin Vivo1

While it is well known that serious illness and inflammation reduce male fertility, the mechanisms involved are poorly understood. In adult male rats, a single injection of lipopolysaccharide at doses that induced either mild or severe inflammation, caused a biphasic decline in Leydig cell testosterone production and gonadotropin responsiveness. In the high dose group only, serum LH levels also were reduced; however, intratesticular testosterone concentrations remained at a level adequate to support qualitatively normal spermatogenesis in both treatment groups. Testicular interstitial fluid formation also declined in a dose-dependent fashion after lipopolysaccharide treatment. In the high dose group only, these hormonal and vascular changes were accompanied by an increase in endothelial permeability, microhemorrhage, and inflammatory cells in the testis, followed by vacuolization of round spermatid nuclei, disruption of Sertoli-germ cell contacts at stages I-IV of the cycle of the seminiferous epithelium, and subsequently apoptosis of spermatocytes at stages II-V. These data indicate that mild inflammation causes local inhibition of Leydig cell function with relatively little spermatogenic damage. The pathological changes in spermatogenic function during severe inflammation are most likely due to direct effects of inflammatory mediators on the seminiferous epithelium or testicular vasculature, rather than inhibition of the brain-pituitary-Leydig cell axis.

Protective effects of manidipine on spermatogenesis in stroke-prone spontaneously hypertensive rats.

1. We evaluated the protective effects of manidipine on spermatogenic damage induced by the hypertensive vascular changes in stroke-prone spontaneously hypertensive rats (SHRSP). 2. Blood pressure reached more than 250 mmHg in SHRSP at 15 weeks of age, and thereafter the hypertensive changes in testicular arterioles developed. Manidipine reduced both the blood pressure and the hypertensive vascular changes. 3. Although immature and mature spermatids greatly diminished in SHRSP at 23 weeks of age, manidipine could preserve almost normal spermatogenesis even at 23 weeks of age. Transferrin concentration in testicular cytosol, which was considered to be indicative of the Sertoli cell function, in SHRSP with manidipine administration was significantly higher than that in SHRSP with no treatment at 23 weeks of age. 4. In conclusion, manidipine could prevent the development of the hypertensive changes in intratesticular arterioles and maintain normal Sertoli cell function. As a result, manidipine protected spermatogenic damage in SHRSP.