Severe Impairment Of Spermatogenesis Research Articles

High-fat diet in mice led to increased severity of spermatogenesis impairment by lead exposure: perspective from gut microbiota and the efficacy of probiotics.

The mechanism of multifactorial spermatogenesis impairment is unclear. This study aimed to investigate the reproductive toxicity of lead (Pb) in mice fed a high-fat diet (HFD) and to delineate the important role of gut microbiota. Results showed that, compared with mice fed a normal diet (ND), Pb exposure caused more severe spermatogenesis impairment in HFD-fed mice, including decreased sperm count and motility, seminiferous tubule injury, serum and intratesticular testosterone decline, and downregulated expression level of spermatogenesis-related genes. Besides, 16S sequencing indicated that HFD-fed mice had increased severity of gut microbiota dysbiosis by Pb exposure compared to ND-fed mice. With fecal microbiota transplantation, the same trend of spermatogenesis impairment occurred in recipient mice, which confirmed the important role of gut microbiota. Moreover, probiotics supplementation restored the gut microbial ecosystem, and thus improved spermatogenic function. Our work suggested that a population with HFD might face more reproductive health risks upon Pb exposure, and revealed an intimate linkage between microbiota dysbiosis and spermatogenesis impairment, accompanied by the potential usefulness of probiotics as prophylactic and therapeutic. © 2022 Society of Chemical Industry.

Effect of Khat (Catha edulis Forsk) extract on testicular maturation in pre-pubertal and pubertal rats: A morphological and biochemical study.

The present study aimed at analysing the effect of Khat plant extract on rat testicular development. Thirty-two weaned male albino rats (4weeks old) were divided into four groups consisting of eight animals each. While control animals received normal saline, rats of groups I, II and III received 100, 200 and 300mg Khat extract per kg body weight dissolved in distilled water by oral gavage daily for 8weeks, respectively. Blood samples were collected in separate heparinized tubes by cardiac puncture from each rat and processed for measuring plasma levels of reproductive hormones LH, FSH, testosterone and prolactin. Five-µm sections were stained with haematoxylin and eosin and examined by light microscope. Some sections were immunostained for protamine-1 representing a biomarker for intact sperm differentiation. The present study clearly demonstrated that Khat extract has a pronounced effect on testicular maturation of developing albino rats at both the morphological and functional levels. Khat-treated groups revealed a significantly low serum testosterone level and severe impairment of spermatogenesis when compared with control animals. The current findings also verified, for the first time, that the final stages of sperm maturation (spermiogenesis) were strongly impaired after administration of Khat extract to experimental rats particularly at a higher dose (300mg/kg body weight). This was proved by the very weak, if any, expression of protamine-1 in the maturing spermatids in Khat-treated rats.

Development of a lipopolysaccharide (LPS)-supplemented adjuvant and its effects on cell-mediated and humoral immune responses in male rats immunized against sperm.

Supplementation with lipopolysaccharide (LPS) from non-pathogenic Escherichia coli was found to enhance the adjuvant effects of a veterinary vaccine adjuvant (ISA 71VG®). Sperm immunization using 71VG as an adjuvant in the immature period induced infertility in 25% of male rats, whereas this increased to 62.5% after immunization with 71VG + LPS or Freund′s complete adjuvant (FCA). Mean testicular weight of non-sterile males in the 71VG + LPS group was significantly lower than that in the 71VG or FCA group. Histological examination of testicular tissue from sterile males demonstrated severe impairment of spermatogenesis due to experimental autoimmune orchitis, a cell-mediated autoimmune condition. The serum anti-sperm titer was elevated in the three sperm-immunized groups relative to male rats treated with adjuvant alone, but the titer was higher in the 71VG + LPS and FCA groups than in the 71VG group. We consider that this LPS-supplemented adjuvant stimulates both humoral and cell-mediated immune responses to an extent comparable to FCA.

Effect of gr/gr microdeletion in partial AZFc deletion on human spermatogenesis

Objectives To inverstigate the effect of gr/gr subdeletion in partial AZFc deletion on human spermatogenesis. Methods We assessed The prevalence of gr/gr deletion in a population of both normospermic and infertile men with severe impairment of spermatogenesis were assessed, the contribution of these gr/gr deletion to male infertility was determined. A combined methodological approach that included the detection of the different DAZ gene copies by sequence nucleotide variant (SNV) analysis and AZFc-specific sequence tagged site (STS) markers was used. Results Type of gr/gr deletion was detected in 27 cases of 278 males with oligozoospermic and 17 cases of 220 donors. There was no difference in the prevalence of gr/gr deletion comparing oligozoospermic and normospermic groups (P=0.438). Of the 27 men with the gr/gr deletion, 23 cases exhibited the doublet deletion of DAZ1/DAZ2 and 1 case showed the DAZ3/DAZ4 deletion. In the normozoospermic population, 16 cases of gr/gr-DAZ3/DAZ4 deletions and one gr/gr-DAZ1/DAZ2 deletion were found. There was a significant difference when comparing gr/gr-DAZ1/DAZ2 deletions vs. gr/gr-DAZ3/DAZ4 deletions in the oligozoospermic and normospermic groups (P=0.000). Conclusions The gr/gr-DAZ3/DAZ4 deletion may not be sufficient to cause spermatogenic impairment. In addition, gr/gr microdeletions, which involve the DAZ1/DAZ2 region, may be a main cause of low sperm concentration and spermatogenic failure in the south chinese population. Key words: Spermatogenesis; Y Chromosome

Endogenous Factors in the Recovery of Reproductive Function After Testicular Injury and Cancer.

The testes are one of the most delicate organs in the male body and highly susceptible to the exogenous influences capable of inducing cell damage. Cancer therapies are well known to negatively affect the male reproductive tract with a severe impairment of spermatogenesis and infertility. The present work aimed to systematically review the available information about the different endogenous factors (hormonal and nonhormonal) that may have protective or advantageous properties on the recovery of male reproductive function after gonadal injury. Furthermore, the perspective that these endogenous molecules could act as cryoprotectants to improve the quality of cryopreserved semen samples was also discussed. The knowledge reviewed herein allowed to identify promising factors able to mitigate the male fertility problems arising either from oncological treatments or other gonadal damage, and opened new possibilities to ameliorate the recovery of spermatogenesis or to preserve fertility.

The polymorphism G4C14-to-A4T14 in p73 gene may affect the susceptibility to male infertility with severe spermatogenesis impairment in Chinese population

ObjectiveThe aim of this study was to explore the association between the polymorphism G4C14-to-A4T14 in the p73 gene and male infertility with severe spermatogenesis impairment in Chinese population. Study designThree hundreds and one infertile patients with severe spermatogenesis impairment (including azoospermia and severe oligospermia) and 252 fertile men were recruited in this study. The polymorphism G4C14-to-A4T14 in the p73 gene was genotyped using polymerase chain reaction and restriction fragment length polymorphism assay. The differences in allelic and genotypic frequencies between patients and controls were evaluated by chi-square test. ResultsThe frequency of allele AT (28.9% vs. 22.4%, P=0.017, OR=1.41, 95% CI=1.07–1.85) in patients with severe spermatogenesis impairment was significantly higher than that in controls, whereas the genotype GC/GC was significantly decreased in patients compared with controls (48.5% vs. 59.1%, P=0.048, OR=0.65, 95% CI=0.46–0.91). ConculusionThe findings of this study suggested that the polymorphism G4C14-to-A4T14 in p73 gene might be associated with severe spermatogenesis impairment and could affect the susceptibility to male infertility with severe spermatogenesis impairment in Chinese population.

ESX1 mRNA expression in seminal fluid is an indicator of residual spermatogenesis in non-obstructive azoospermic men.

Is the presence of ESX1 mRNA in seminal fluid (SF) an indicator of residual spermatogenesis in men with non-obstructive azoospermic (NOA)? ESX1 mRNA in SF is a suitable molecular marker for predicting the presence of residual spermatogenesis in testis. ESX1 is an X-linked homeobox gene whose expression in testis is restricted to germ cells. We previously reported, in the testicular biopsies from azoospermic men, a positive correlation between the presence of ESX1 mRNA and residual spermatogenesis. We investigated ESX1 mRNA expression in 70 testicular fragments (TF) and 56 (SF) of 70 NOA men. As controls, we analyzed 8 TF from men with obstructive azoospermic (OA) and 9 SF from normozoospermic men. For all patients we considered the histological classification of testis biopsies and the recovery of spermatozoa by surgical procedures. Relative ESX1 mRNA expression was evaluated by quantitative RT-PCR using the ΔΔCt method. The results were compared with the recovery of spermatozoa at surgery. In TF from NOA patients we found that: (i) ESX1 mRNA level was significantly decreased as the severity of spermatogenic defects increased (P < 0.0001, one-way analysis of variance); (ii) the presence of ESX1 mRNA can predict the success of sperm retrieval (sensitivity: 80%). In SF from NOA patients we found that: (i) ESX1 mRNA was present in 78.5% of NOA men; (ii) the presence of ESX1 mRNA could predict the success of sperm retrieval (sensitivity: 84%). Spermatozoa were recovered at surgery in 5 out of 12 patients whose SF was negative for ESX1 mRNA expression. We think that discrepancies between molecular and clinical results could be reduced by analyzing more than one ejaculate from each man. The data confirm that the ESX1 transcript in the semen of men with NOA is a suitable molecular marker for predicting the presence of residual foci of spermatogenesis in the testis. The implication of these results is that some patients 'with azoospermia', although having a severe impairment of spermatogenesis, could still maintain residual foci of spermatogenesis in limited areas of the testes, not always recovered by surgery. This work was supported by the Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico: Ricerca Corrente [grant number RC2014/519-02] to M.M. and from ASM onlus 2010-2011 to M.M. The authors declare that they have no conflict of interest.

Chromosome abnormalities in embryos derived from microsurgical epididymal sperm aspiration and testicular sperm extraction

ObjectiveTo evaluate the patterns of chromosome abnormalities in embryos derived from intracytoplasmic sperm injection (ICSI) in microsurgical epididymal sperm aspiration (MESA) or testicular sperm extraction (TESE) in comparison to embryos that are derived from naturally ejaculated (EJAC) patients. Materials and methodsMale partners with azoospermia who required MESA or TESE for ICSI were studied for chromosomal abnormalities. The ICSI patients with EJAC sperm served as the control group. Preimplantation genetic diagnosis (PGD) was performed by fluorescence in situ hybridization (FISH). Chromosome abnormalities were categorized as polyploidy, haploidy, aneuploidy, and complex abnormality (which involves more than two chromosomes). Fertilization, embryo development, and patterns of chromosome abnormalities were accessed and evaluated. ResultsThere was no difference between the MESA, TESE, and EJAC patient groups in the rates of fertilization and pregnancy and the percentages of euploid embryos. In all three groups, less than one-half of the embryos for each group were normal (41 ± 31%, 48 ± 38%, and 48 ± 31% in MESA, TESA, and EJAC, respectively). Complex chromosomal abnormality was significantly more frequent in the MESA group than in the EJAC group (48.3% vs. 26.5%, respectively; p < 0.001). Furthermore, the overall pattern of chromosomal aneuploidy was similar among all three studied groups. ConclusionWe suggest that MESA and TESE, followed by ICSI and PGD, appear to be acceptable approaches for treating men with severe spermatogenesis impairment.

Necrosis Is the Dominant Cell Death Pathway in Uropathogenic Escherichia coli Elicited Epididymo-Orchitis and Is Responsible for Damage of Rat Testis

Male infertility is a frequent medical condition, compromising approximately one in twenty men, with infections of the reproductive tract constituting a major etiological factor. Bacterial epididymo-orchitis results in acute inflammation most often caused by ascending canalicular infections from the urethra via the continuous male excurrent ductal system. Uropathogenic Escherichia coli (UPEC) represent a relevant pathogen in urogenital tract infections. To explore how bacteria can cause damage and cell loss and thus impair fertility, an in vivo epididymo-orchitis model was employed in rats by injecting UPEC strain CFT073 into the vas deference in close proximity to the epididymis. Seven days post infection bacteria were found predominantly in the testicular interstitial space. UPEC infection resulted in severe impairment of spermatogenesis by germ cell loss, damage of testicular somatic cells, a decrease in sperm numbers and a significant increase in TUNEL (+) cells. Activation of caspase-8 (extrinsic apoptotic pathway), caspase-3/−6 (intrinsic apoptotic pathway), caspase-1 (pyroptosis pathway) and the presence of 180 bp DNA fragments, all of which serve as indicators of the classical apoptotic pathway, were not observed in infected testis. Notably, electron microscopical examination revealed degenerative features of Sertoli cells (SC) in UPEC infected testis. Furthermore, the passive release of high mobility group protein B1 (HMGB1), as an indication of necrosis, was observed in vivo in infected testis. Thus, necrosis appears to be the dominant cell death pathway in UPEC infected testis. Substantial necrotic changes seen in Sertoli cells will contribute to impaired spermatogenesis by loss of function in supporting the dependent germ cells.

The Semen Quality of 1158 Men With Testicular Cancer at the Time of Cryopreservation: Results of the French National CECOS Network

Testicular cancer is the most common cancer in young men. Several studies have reported an alteration in semen quality in nonseminoma tumors, but this result has not been confirmed in all of the published data. We performed a retrospective study in a population of 1158 men with testicular cancer who banked sperm between 1999 and 2003 in 11 French Centre d'Etude et de Conservation des Oeufs et du Sperme humain laboratories. Our study evaluated prefreeze and postthaw sperm parameters according to patient medical history, tumor histological type, and disease stage. Pure seminomas were found in 48% of our population. Testicular cancer was generally diagnosed at stage I. In cases of a history of unilateral cryptorchidism, testicular cancer occurred preferentially in the maldescended testis. Semen samples were preferentially collected after orchiectomy. The sperm concentration and total sperm number were significantly lower before orchiectomy in seminomas compared with nonseminoma tumors (P < .001). After orchiectomy, these parameters decreased for nonseminoma tumors and did not vary for seminomas. Semen parameters were more severely impaired for stage III tumors, and when patients had a history of cryptorchidism or when they were less than 20 years of age. Azoospermia was more frequently observed before than after orchiectomy. In this study, we determined that sperm cryobanking should preferentially be performed before orchiectomy and that testicular sperm extraction concurrent with orchiectomy should be used in severe spermatogenesis impairment. Our study highlights that seminomas alter sperm production more significantly than nonseminoma tumors and seem to preferentially impair spermatogenesis in tumor-bearing testes.

Cryopreservation of individually selected sperm: methodology and case report of a clinical pregnancy

ObjectiveTo describe a new technique for freezing individually isolated spermatazoa from testicular biopsies, epididymal aspirates and oligospermic semen samplesMethodsSamples were evaluated for the presence of motile sperm before cryopreservation. Motile or twitching sperm were isolated with an ICSI needle for single sperm cryopreservation. Selected sperm were loaded on the High Security Straw (HSV; Irvine Scientific; Irvine,CA), in ~0.5 µl of fluid to facilitate recovery. The sample was also frozen using conventional methodology in cryovials (100–1000 µl aliquots). In both freezing techniques, the samples were slow cooled. Test-yolk buffer-glycerol (Irvine) was used as the cryoprotectant. Test-thaws were performed to assess sperm recovery and motility.ResultsSix men with azoospermia had single sperm cryopreservation, as well as freezing aliquots of their testicular or epididymal sperm in traditional cryovials. In addition, two men with oligospermia also had individual sperm selected and frozen. In all 8 cases, the ~0.5 µl of fluid containing sperm was quite easily unloaded from the HSV straw during thawing. The percent sperm recovery ranged from 33% to 100%. Motility was evident in all but one sample. In six cases, the sperm were used for intracytoplasmic sperm injection of mature oocytes. Fertilization occurred in all but one case. In this study, we report the first clinical pregnancy with this technique. This pregnancy was remarkable in that a single motile sperm identified and selected in the initial testicular preparation was successfully frozen. We were able to subsequently recover this sperm, fertilize an oocyte and the resultant embryo gave rise to a live birth. The methodology described in this preliminary report offers a new modality for sequestering small numbers of sperm. It may be particularly useful in cases involving severe impairment of spermatogenesis, where extensive screening may be necessary to find a few viable sperm.

Reply to: [Use of hydroxyurea from childhood to adult age in sickle cell disease: semen analysis. Haematologica 2008; 93:e67

We read with great interest the observation by Lukusa and Vermylen of 4 patients with Sickle Cell Disease (SCD), treated by hydroxyurea (HU) in childhood and displaying severe impairment of spermatogenesis. The adult male patients, in the series we have reported (Haematologica, 2008, 93:988–93),

Routine screening for classical azoospermia factor deletions of the Y chromosome in azoospermic patients with Klinefelter syndrome

To evaluate the occurrence of classical azoospermia factor (AZF) deletions of the Y chromosome as a routine examination in azoospermic subjects with Klinefelter syndrome (KS). Blood samples were collected from 95 azoospermic subjects with KS (91 subjects had a 47,XXY karyotype and four subjects had a mosaic 47,XXY/46,XY karyotype) and a control group of 93 fertile men. The values of testosterone, follicle stimulating hormone (FSH) and luteinizing hormone (LH) were measured. To determine the presence of Y chromosome microdeletions, polymerase chain reaction (PCR) of five sequence-tagged site primers (sY84, sY129, sY134, sY254, sY255) spanning the AZF region, was performed on isolated genomic DNA. Y chromosome microdeletions were not found in any of the 95 azoospermic subjects with KS. In addition, using similar conditions of PCR, no microdeletions were observed in the 93 fertile men evaluated. The level of FSH in KS subjects was higher than that in fertile men (38.2 +/- 10.3 mIU/mL vs. 5.4 +/- 2.9 mIU/mL, P < 0.001) and the testosterone level was lower than that in the control group (1.7 +/- 0.3 ng/mL vs. 4.3 +/- 1.3 ng/mL, P < 0.001). Our data and review of the published literature suggest that classical AZF deletions might not play a role in predisposing genetic background for the phenotype of azoospermic KS subjects with a 47,XXY karyotype. In addition, routine screening for the classical AZF deletions might not be required for these subjects. Further studies including partial AZFc deletions (e.g. gr/gr or b2/b3) are necessary to establish other mechanism underlying severe spermatogenesis impairment in KS.

Quantification of DDX3Y, RBMY1, DAZ and TSPY mRNAs in testes of patients with severe impairment of spermatogenesis

Y chromosome microdeletion is the most important genetic cause of impairment of spermatogenesis. Nevertheless, a significant proportion of patients with spermatogenic failure do not have this condition. This study investigated the expression level of AZF genes, DDX3Y (DBY), RBMY1, DAZ and TSPY in testicular tissues of 42 subjects with impaired spermatogenesis compared with 33 with normal spermatogenesis. Histopathological evaluation was performed in all subjects and tissues were classified according to Johnsen Score. Transcript amounts were determined by quantitative-competitive RT-PCR. Patients with complete Sertoli cell-only syndrome (SCOS) did not exhibit RBMY1, DAZ and TSPY gene expression, however, we detected very low expression of DDX3Y transcript. Tissue samples with focal SCOS showed significantly decreased expression of all genes (P < 0.001). Maturation arrest and hypospermatogenesis tissues expressed significantly low levels of DDX3Y testicular transcript (P < 0.001), while the mRNA levels of the other genes were similar to that in tissues from the normal spermatogenesis group. Negative or diminished gene expression of DDX3Y, RBMY1, DAZ and TSPY in tissues samples with SCOS or focal SCOS reflects the absence or the lower number of germ cells, respectively. The finding that the testicular transcript of DDX3Y is significantly decreased in patients with severe spermatogenenic failure, especially in those presenting maturation arrest, suggests an important role of DDX3Y during spermatogenesis.

AZFc partial deletions in Chilean men with severe spermatogenic failure

To determine the prevalence of AZFc subdeletions in infertile Chilean men with severe spermatogenic impairment. Prospective analysis. University infertility clinic. Ninety-five secretory azo/oligozoospermic men without AZFc Y chromosome microdeletions: 71 whose testicular histology showed severe spermatogenic impairment and 24 who exhibited reduced testicular volume and elevated serum FSH levels. As controls, we studied 77 men (50 fertile and/or normozoospermic, and 27 with azoospermia and normal spermatogenesis). Peripheral blood was drawn to obtain genomic DNA for polymerase chain reaction (PCR) digestion assays of DAZ-sequence nucleotide variants and for AZFc-STS PCR after a complete testicular characterization (biopsy, hormonal, and physical evaluation). DAZ genes and AZFc subdeletion types. In cases we observed two "gr/gr" subdeletions (2.1%), one with absence of DAZ1/DAZ2 (g1/g2 subtype), and the other with absence of DAZ3/DAZ4 (r2/r4 subtype). Additionally, we found a g1/g3 subdeletion in a patient with Sertoli-cell-only syndrome. In controls, we observed two gr/gr subdeletions with absence of DAZ1/DAZ2 (2.6%) in a fertile/normozoospermic and in an obstructive azoospermic man. AZFc subdeletions do not seem to cause severe impairment of spermatogenesis. Moreover, gr/gr-DAZ1/DAZ2 subdeletions do not appear to affect fertility in Chilean men.

Predictive factors for an increased risk of sperm aneuploidies in oligo‐astheno‐teratozoospermic males

Patients with severe spermatogenesis impairment can now successfully father a child thanks to the use of intracytoplasmic sperm injection (ICSI). In oligozoospermic patients, many studies have reported significantly higher sperm aneuploidy rates and therefore an increased risk of transmitting a chromosomal abnormality via the injection of abnormal spermatozoa. However, the frequency of aneuploidy is highly variable between patients. The aim of the present work was to identify clinical and biological factors, which, together with non-obstructive oligozoospermia, could be predictive of elevated sperm aneuploidies. The sperm aneuploidy rates for chromosomes X, Y, 13, 18 and 21 were assessed in 31 infertile men with well-characterized spermatogenesis impairment, and in a population of control men with proven fertility. The frequency of sperm aneuploidy was compared between several patient subgroups according to their clinical and biological factors. Nearly half of the oligozoospermic males (15/31) had a significantly increased disomy rate for at least one of the five chromosomes compared with that observed in the control population (mean disomy rates + 1.96 standard deviation). Factors significantly associated with higher numbers of aneuploid sperm were cigarette smoking, an elevated follicle-stimulating hormone level, a sperm concentration less than 1 m/mL, and a severe teratozoospermia. Hence, several factors predictive of an increased risk of sperm aneuploidy rates were identified in ICSI male candidates with a non-obstructive oligozoospermia.

Perturbation of spermatogenesis by androgen antagonists directly injected into seminiferous tubules of live mice

Natural and artificial substances present in the environment can affect our health. Testicular toxicants in particular are troublesome, because they disturb gonadal function of males. Translocation of substances into the seminiferous epithelium where sperm production proceeds is restricted due to the blood-testis barrier, but this permeability barrier temporarily disappears under physiological and sub-physiological conditions. This means that any substance could enter the seminiferous epithelium and disturb sperm production. To reduce the risk posed by such toxins, it is important to accurately determine which substances possess the toxicity. However, existing assay systems are not satisfactory in terms of both accuracy and sensitivity. Here, we report the establishment of such a system. We injected the androgen antagonists, flutamide and vinclozolin, directly into seminiferous tubules of live mice, which had been treated with busulfan for a temporal arrest of spermatogenesis, and the testes were histologically examined to see the effect of the injected materials on spermatogenesis that was in the process of recovery. The injection of either substance brought about a severe impairment of spermatogenesis at an amount over a million times smaller than that used in the previous assay systems where animals are administered with test substances outside of the testis. In contrast, these androgen antagonists at the same doses showed lesser effects when intratubularly or intraperitoneally administered into mice that had not been pretreated with busulfan. We propose that the method adopted in this study is a novel assay system to identify potential testicular toxicants.

Experimental testicular torsion: Reperfusion blood flow and subsequent testicular venous plasma testosterone concentrations

To examine the effect of torsion on subsequent testicular venous plasma testosterone concentrations (TVT) and to determine the relationship between the TVT values 30 days after torsion repair and testicular reperfusion immediately after torsion repair, because testicular torsion followed by repair induces an ischemia/reperfusion injury of the testis. Adult male rats were subjected to 1 hour of 720 degrees testicular torsion, a time and degree of torsion that has been shown to cause severe impairment of spermatogenesis. Testicular microvascular perfusion before torsion, during torsion, and 5 minutes after torsion repair was determined by laser Doppler flowmetry. The animals were evaluated 3 days and 30 days later for microvascular perfusion and TVT. Experimental torsion significantly reduced testicular vascular perfusion. Five minutes after torsion repair, the mean flow values had returned to approximately 70% of the pretorsion values. Testicular torsion significantly reduced TVT at both 3 and 30 days after torsion repair. TVT 30 days after torsion repair was significantly, but inversely, related to reperfusion values immediately after torsion repair. These results demonstrate that the minimal duration and degree of torsion known to cause loss of spermatogenesis in the rat also causes a significant reduction in testicular androgen production in the long term. This effect was inversely related to the reperfusion values immediately after torsion repair. This suggests that reperfusion/oxidative stress may play a role in Leydig cell dysfunction, as well as by acting directly in germ cell apoptosis.

Misregulation of histone acetylation in Sertoli cell-only syndrome and testicular cancer.

In many species, including humans, chromatin remodelling during spermiogenesis is initiated with a marked increase in histone acetylation in elongating spermatids. We have investigated whether this process is disturbed when spermatogenesis is defective or in human testicular tumours. For this purpose, the presence of highly acetylated histone H4 was detected on testicular sections from men with a severe impairment of spermatogenesis of several origins, as well as in different types of testicular tumours. In most tubules devoid of germinal cells (including SCO, Sertoli cell only syndromes) or lacking spermatocytes and spermatids, the Sertoli cells' nuclei showed a global increase in histone H4 acetylation. A similar observation was made in the peritumoral seminiferous tubules of testicular tumour tissues, whenever they were lacking germinal cells, with carcinoma in situ (CIS) cells being hypoacetylated. The global hyperacetylation of elongating spermatids during spermatogenesis could be part of an intercellular signalling pathway involving Sertoli cells and germinal cells, which could be disturbed in cases of severe spermatogenesis impairment, as well as in tubes surrounding germ cells in testicular tumours.

Targeted Disruption of Intracellular Type I Platelet Activating Factor-acetylhydrolase Catalytic Subunits Causes Severe Impairment in Spermatogenesis

Intracellular type I platelet activating factor-acetylhydrolase is a phospholipase that consists of a dimer of two homologous catalytic subunits alpha1 and alpha2 as well as LIS1, a product of the causative gene for type I lissencephaly. LIS1 plays an important role in neuronal migration during brain development, but the in vivo function of the catalytic subunits remains unclear. In this study, we generated alpha1- and a2-deficient mice by targeted disruption. alpha1(-/-) mice are indistinguishable from wild-type mice, whereas alpha2(-/-) male mice show a significant reduction in testis size. Double-mutant male mice are sterile because of severe impairment of spermatogenesis. Histological examination revealed marked degeneration at the spermatocyte stage and an increase of apoptotic cells in the seminiferous tubules. The catalytic subunits are expressed at high levels in testis as well as brain in mice. In wild-type mice, alpha2 is expressed in all seminiferous tubule cell types, whereas alpha1 is expressed only in the spermatogonia. This expression pattern parallels the finding that deletion of both subunits induces a marked loss of germ cells at an early spermatogenic stage. We also found that the LIS1 protein levels, but not the mRNA levels, were significantly reduced in alpha2(-/-) and double-mutant mice, suggesting that the catalytic subunits, especially alpha2, are a determinant of LIS1 expression level.