Sustained azoospermia in squirrel monkey, Saimiri sciureus, resulting from a single intratesticular glycerol injection

Evaluation of chemical castration using intra-testicular injection of zinc gluconate into the testis of the male donkey versus surgical castration: antimullerian hormone as an endpoint marker

BACKGROUND

Chemical castration of male animals is an alternative to surgical castration for inducing azoospermia, consequent sterility. Intra-testicular injection of zinc gluconate has been used for chemical castration in several animal species. However, its application to equine species, such as donkeys, has yet to be reported. This study aimed to evaluate the use of zinc gluconate for the chemical castration of male donkeys and to compare its effectiveness relative to routine surgical castration. For this purpose, investigations of serum testosterone and anti-Müllerian hormone levels, testicular ultrasonographic echogenicity, and histopathological findings were performed.

METHODS

Fourteen clinically healthy adult male donkeys were randomly and equally divided into two groups. The donkeys in group I (n = 7) underwent surgical castration. The donkeys in group II (n = 7) received intra-testicular zinc gluconate injections. The donkeys were kept under close clinical observation for 60 days. Abnormalities in donkey behavior and gross alterations in the external genitalia were recorded daily. Serum testosterone and anti-Müllerian hormone (AMH) levels were measured 15 days before the start of the treatment and 15, 30, 45, and 60 days after treatment. The testicles of group II donkeys were evaluated ultrasonographically. At the end of the study, the testes were removed and histologically examined.

RESULTS

Serum testosterone levels significantly declined compared to pre-castration levels in surgically castrated donkeys (group I), but donkeys exposed to chemical castration (group II) showed a non-significant reduction in testosterone levels. Donkeys in the surgical group had considerably lower serum AMH levels. In contrast, there was a non-significant (p > 0.05) increase in AMH levels in the chemical group compared with the pre-sterilization level. In addition, ultrasonographic examination revealed that the testicular echo-density had changed, as observed by a few scattered hyperechoic regions throughout the entire testis parenchyma. The histopathological investigation confirmed the presence of necrosis of the spermatogenic epithelium, increased thickness of the basement membrane of the seminiferous tubules, marked interstitial fibrosis, and shrinkage of the seminiferous tubules. Furthermore, syncytial giant cells were present in the lumen of seminiferous tubules and were associated with Sertoli cell vacuolation. Donkeys subjected to chemical castration (group II) had orchitis, as confirmed histopathologically.

CONCLUSION

Intra-testicular injection of zinc gluconate resulted in histopathological and ultrasonographic testicular changes in adult male donkeys, which may affect their reproductive potential. However, it did not significantly alter serum testosterone or AMH levels, indicating that it cannot be used as a substitute for surgical castration in male donkeys.

CFTR modulates aquaporin-mediated glycerol permeability in mouse Sertoli cells

The cystic fibrosis transmembrane conductance regulator (CFTR) is an anion channel that is crucial for fluid homeodynamics throughout the male reproductive tract. Previous evidence shed light on a potential molecular partnership between this channel and aquaporins (AQPs). Herein, we explore the role of CFTR on AQPs-mediated glycerol permeability in mouse Sertoli cells (mSCs). We were able to identify the expression of CFTR, AQP3, AQP7, and AQP9 in mSCs by RT-PCR, Western blot, and immunofluorescence techniques. Cells were then treated with CFTRinh-172, a specific CFTR inhibitor, and its glycerol permeability was evaluated by stopped-flow light scattering. We observed that CFTR inhibition decreased glycerol permeability in mSCs by 30.6% when compared to the control group. A DUOLINK proximity ligation assay was used to evaluate the endogenous protein-protein interactions between CFTR and the various aquaglyceroporins we identified. We positively detected that CFTR is in close proximity with AQP3, AQP7, and AQP9 and that, through a possible physical interaction, CFTR can modulate AQP-mediated glycerol permeability in mSCs. As glycerol is essential for the control of the blood-testis barrier and elevated concentration in testis results in the disruption of spermatogenesis, we suggest that the malfunction of CFTR and the consequent alteration in glycerol permeability is a potential link between male infertility and cystic fibrosis.

Efficacy of Intratesticular Glycerol Injection as Male Cat Contraception in Comparison with Two Surgical Approaches

The objectives of the current study were to compare the use of a single bilateral intratesticular injection of 2 different volumes of glycerol 70% (0.5 and 1.0 mL) as a method of chemical sterilization and the application of 2 surgical procedures (orchiectomy and vasoligation). Animals were classified into 4 groups. Group 1:10 cats were subjected to a conventional bilateral orchidectomy. Group 2:6 cats were subjected to a bilateral vasoligation of the testicular blood supply without removing the testicles. Group 3:7 cats were subjected to a single intratesticular injection of 0.5 mL glycerol bilaterally and Group 4:7 cats were subjected to a single intratesticular injection of 1.0 mL glycerol bilaterally. Serum testosterone concentration (ng/mL) and average testicular length (cm) were measured just before (control) and weekly after orchiectomy (only serum testosterone concentration), vasoligation, and intratesticular treatment for 3 consecutive weeks. After 2 months from testicular vasoligation (group 2) and intratesticular administration (group 3 and 4), castration was performed for all cats. The epididymal sperm count and the histopathological findings were recorded for all groups after the orchidectomy. In group 2 serum testosterone level was significantly (P ˂ .01) decreased from (4.14 ± 1.10 ng/mL) before vasoligation (control) to (1.71 ± 0.34 ng/mL) 3 weeks postoperation. In group 4 a significant (P ˂ .01) decrease in serum testosterone concentration was recorded 2 and 3 weeks postinjection (1.41 ± 0.31 and 1.32 ± 0.21 ng/mL, respectively). There was a significant decrease in the testicular length 1 week after the vasoligation (group 2) and the testicular treatment (group 4) compared with preoperative controls of the 2 groups. Besides, the epididymal samples collected from groups (2 and 4) showed azoospermia. In conclusion, a bilateral intratesticular injection of 1.0 mL glycerol (70%) as a chemical method of tomcat sterilization can replace the surgical orchidectomy besides being less invasive and less traumatic and gave better results than using the intratesticular injection of 0.5 mL glycerol.

Acute reproductive toxicology after intratesticular injection of silver nanoparticles (AgNPs) in Wistar rats

This study aimed to evaluate the effects of an intratesticular injection of silver nanoparticles (AgNPs) on reproductive parameters and health of rats, and to evaluate the AgNPs biodistribution in order to develop a nanotechnological contraceptive agent for male animals. Treated animals received 220 μL of AgNPs solution (0.46 µg-Ag/ml) in each testicle and were euthanized: seven, 14, 28, and 56 days after injection. A significant decrease (p < 0.05) in the percentage of motile sperm in D7 (8.8%) was observed, comparing to the control (73.3%), D14 (86.0%), D28 (68.2%), and D56 (90.0%) groups. D7 group also presented a decrease (p < 0.05) in the percentage of normal spermatozoa. Additionally, D7 group showed an increase (p < 0.05) in abnormal midpiece and sperm head morphology compared to the Control group. Seminiferous tubules presented all germline cell types and spermatozoa for all groups. However, D7 group did not present spermatozoa in the epididymis, whereas some spermatozoa and cellular debris were visible in D14 and D28 groups. All animals presented hematological parameters, creatinine, and alanine aminotransferase values within the normal limits for Wistar rats. The percentage of silver found in the liver was always higher than in the other organs analyzed. A pioneering mathematical model is proposed, from which the half-life time of silver in the liver (17 days), spleen (23 days), lungs (30 days), and kidneys (35 days) was extracted. In conclusion, some acute and severe toxic effects were observed in sperm cells following intratesticular injection of AgNPs, although these effects were reversible. No adverse effects to general animal health were observed.

Endogenously produced LG3/4/5-peptide protects testes against toxicant-induced injury

Laminin-α2 chain is one of the major constituent proteins of the basement membrane in the mammalian testis. The laminin-type globular (LG) domains of LG3, 4 and 5 (LG3/4/5, an 80 kDa fragment) can be cleaved from laminin-α2 chain at the C-terminus via the action of matrix metalloproteinase 9 (MMP-9). This LG3/4/5 is a biologically active fragment, capable of modulating the Sertoli cell blood–testis barrier (BTB) function by tightening the barrier both in vitro and in vivo. Overexpression of LG3/4/5 cloned into a mammalian expression vector pCI-neo in Sertoli cells in a Sertoli cell in vitro model with a functional BTB also protected Sertoli cells from cadmium chloride (CdCl₂, an environmental toxicant) mediated cell injury. Importantly, overexpression of LG3/4/5 in the testis in vivo was found to block or rescue cadmium-induced BTB disruption and testis injury. LG3/4/5 was found to exert its BTB and spermatogenesis promoting effects through corrective spatiotemporal expression of actin- and MT-based regulatory proteins by maintaining the cytoskeletons in the testis, illustrating the therapeutic implication of this novel bioactive fragment.

Safety Assessment of Glycerin as Used in Cosmetics

This is a safety assessment of glycerin as used in cosmetics. Glycerin functions as a denaturant, fragrance ingredient, hair conditioning agent, humectant, oral care agent, oral health-care drug, skin protectant, skin conditioning agent-humectant, and viscosity-decreasing agent. The Cosmetic Ingredient Review Expert Panel (Panel) reviewed relevant animal and human data. The Panel concluded that glycerin is safe as a cosmetic ingredient in the practices of use and concentration described in this safety assessment.

Open/close-ended vasectomy technique by single incision on vervet monkeys (Chlorocebus pygerythrus)

Vervet monkeys (Chlorocebus pygerythrus), considered a species of "least concern" by the International Union for Conservation of Nature (IUCN), are widely maintained at primate sanctuaries in South Africa. Permanent surgical contraception is a necessary method for the management of this species in captivity. In this study, a new vasectomy technique was evaluated and involves a prescrotal approach with only one surgical incision, aiming to excise a piece of vas deferens, leaving open the testicular side, and creating a loop on the prostatic side to avoid future recanalization. The birth rate was studied to assess the success of the technique. This technique significantly reduced breeding in the study population from 33 births in the first year to four births during the last year of the study. These results show that this type of vasectomy is a fast, simple, and safe technique for controlling monkey populations in sanctuaries.

Chemical sterilization with intratesticular administration of zinc gluconate in adult dogs: a preliminary report

BACKGROUND

Chemical sterilization with zinc gluconate is being developed due to its permanent contraceptive effect in prepubertal dogs. In this study, five healthy adult dogs were selected randomly. Semen samples were collected and analyzed before the study to confirm normal testicular function. Under general anesthesia, pH neutralized zinc gluconate was injected directly into their testes. Testes diameter, ultrasonographic appearance, changes in the percentage of white blood cells, and testosterone concentration were monitored twice a week before and 1 month after the injection. At the end of the study, the dogs were castrated and their testes were removed for histopathological evaluation.

RESULTS

The general health of all dogs was normal after the injection. The appearance of testicular swelling was limited within 2 days of treatment. The average diameter of left and right testes was 2.48 and 2.03 cm before the injection and reached to diameter 2.12 and 2.15 cm, respectively, at the end of the study. Serum testosterone concentration was 4.2 ng/ml at the start and 4 ng/ml at the end of the study. The percentage of white blood cells at the start and end of the study were within normal ranges reported for dogs. Histopathological analyses indicate a degeneration of germ cells in seminiferous tubules, but Leydig cells retained their structure.

CONCLUSIONS

Therefore, It is inferred that the injection of pH neutralized zinc gluconate into the adult dogs' testes resulted in the loss of sperm-producing tissue without affecting the production of testosterone and the general health of adult dogs.

Estrogen Modulates Glycerol Permeability in Sertoli Cells through Downregulation of Aquaporin-9

High 17β-Estradiol (E2) levels are known to cause alterations of spermatogenesis and environments throughout the male reproductive tract. Sertoli cells (SCs) ensure an adequate environment inside the seminiferous tubule. Glycerol stands as essential for the maintenance of blood⁻testis barrier created by SCs, however, the role of E2 in this process is not known. Herein, we hypothesized that the effect of E2 on glycerol permeability in mouse SCs (mSCs) could be mediated by aquaglyceroporins. The expression of aquaglyceroporins was assessed by RT-PCR and qRT-PCR. Glycerol permeability was evaluated by stopped-flow light scattering. We were able to identify the expression of AQP3 and AQP9 in mSCs where AQP9 is more abundant than AQP3. Our results show that high E2 levels decrease AQP9 mRNA abundance with no influence on AQP3 in mSCs. Interestingly, high E2 levels decreased mSCs' permeability to glycerol, while downregulating AQP9 expression, thus suggesting a novel mechanism by which E2 modulates fluid secretion in the testis. In conclusion, E2 is an important regulator of mSCs physiology and secretion through changes in AQP9 expression and function. Thus, alterations in glycerol permeability induced by E2 may be the cause for male infertility in cases associated with the presence of high E2 levels.

Evaluation of chemical castration with calcium chloride versus surgical castration in donkeys: testosterone as an endpoint marker

BACKGROUND

For the last few years, researchers have been interested in developing a method for chemical sterilization which may be a better alternative to surgical castration. An ideal chemical sterilant would be one that effectively arrests spermatogenesis and androgenesis as well as libido with absence of toxic or other side effects. Calcium chloride in various solutions and concentrations has been tested in many animal species, but few studies have been evaluated it in equines as a chemical sterilant. So, the objective of this study was to evaluate the clinical efficacy of chemical castration with 20% calcium chloride dissolved in absolute ethanol in comparison with surgical castration in donkeys based on the changes in the serum testosterone level and the histopathological changes in treated testes.

METHODS

Twelve clinically healthy adult male donkeys were used in this study. Donkeys were divided randomly and equally into two groups: a surgical (S) group (n = 6) and a chemical (C) group (n = 6). Animals in the (S) group were subjected to surgical castration while those in the (C) group received a single bilateral intratesticular injection of 20% calcium chloride dissolved in absolute ethanol (20 ml/testis). Animals were kept under clinical observation for 60 days. Changes in animals' behavior and gross changes in external genitalia were monitored daily. Serum concentrations of testosterone were measured prior to treatment and at 15, 30, 45 and 60 days post-treatment. Testicles in the (C) group were examined histopathologically at the end of the experiment.

RESULTS

Chemical castration with intratesticular calcium chloride vs. surgical castration failed to reduce serum concentrations of testosterone throughout the whole duration of the study; however it induced orchitis that was evident by focal necrotic areas in seminiferous tubules, cellular infiltration of neutrophils, proliferative intertubular fibrosis with a compensatory proliferation of Leydig cells. Donkeys tolerated the intratesticular injection of calcium chloride. There were no detectable changes in the general health status of the animals with the exception of swelling in external genitalia, scrotal ulcerations and fistulas. Food and water consumption and the gait of animals remained unaffected.

CONCLUSION

Intratesticular calcium chloride can't be considered an effective method for chemical castration in donkeys.

Toxicants target cell junctions in the testis: Insights from the indazole-carboxylic acid model

There are numerous types of junctions in the seminiferous epithelium which are integrated with, and critically dependent on the Sertoli cell cytoskeleton. These include the basal tight junctions between Sertoli cells that form the main component of the blood–testis barrier, the basal ectoplasmic specializations (basal ES) and basal tubulobulbar complexes (basal TBC) between Sertoli cells; as well as apical ES and apical TBC between Sertoli cells and the developing spermatids that orchestrate spermiogenesis and spermiation. These junctions, namely TJ, ES, and TBC interact with actin microfilament-based cytoskeleton, which together with the desmosomal junctions that interact with the intermediate filament-based cytoskeleton plus the highly polarized microtubule-based cytoskeleton are working in concert to move spermatocytes and spermatids between the basal and luminal aspect of the seminiferous epithelium. In short, these various junctions are structurally complexed with the actin- and microtubule-based cytoskeleton or intermediate filaments of the Sertoli cell. Studies have shown toxicants (e.g., cadmium, bisphenol A (BPA), perfluorooctanesulfonate (PFOS), phthalates, and glycerol), and some male contraceptives under development (e.g., adjudin, gamendazole), exert their effects, at least in part, by targeting cell junctions in the testis. The disruption of Sertoli–Sertoli cell and Sertoli–germ cell junctions, results in the loss of germ cells from the seminiferous epithelium. Adjudin, a potential male contraceptive under investigation in our laboratory, produces loss of spermatids from the seminiferous tubules through disruption of the Sertoli cell spermatid junctions and disruption of the Sertoli cell cytoskeleton. The molecular and structural changes associated with adjudin administration are described, to provide an example of the profile of changes caused by disturbance of Sertoli-germ cell and also Sertoli cell-cell junctions.

Regulation of male fertility by CFTR and implications in male infertility

BACKGROUND

The cystic fibrosis transmembrane conductance regulator (CFTR) is a cAMP-activated Cl(-) and HCO(3)(-) conducting channel, mutations of which are known to be associated with male infertility. However, the underlying mechanisms remain elusive.

METHODS

Literature databases were searched for papers on the topics related to CFTR and male fertility and infertility with relevant keywords. Unpublished data from authors' laboratory were also included for analysis.

RESULTS

Clinical evidence shows increased mutation frequency or reduced CFTR expression in men with congenital bilateral absence of vas deferens (CBAVD) or sperm abnormalities, such as azoospermia teratospermia and oligoasthenospermia. Studies on primary rodent Sertoli cells and germ cells, as well as testes from CFTR knockout mice or a cryptorchidism model, yield findings indicating the involvement of CFTR in spermatogensis through the HCO(3)(-)/sAC/cAMP/CREB(CREM) pathway and the NF-κB/COX-2/PGE(2) pathway. Evidence also reveals a critical role of CFTR in sperm capacitation by directly or indirectly mediating HCO(3)(-) entry that is essential for capacitation. CFTR is emerging as a versatile player with roles in mediating different signaling pathways pertinent to various reproductive processes, in addition to its long-recognized role in electrolyte and fluid transport that regulates the luminal microenvironment of the male reproductive tract.

CONCLUSIONS

CFTR is a key regulator of male fertility, a defect of which may result in different forms of male infertility other than CBAVD. It would be worthwhile to further investigate the potential of developing novel diagnostic and contraceptive methods targeting CFTR.

Epidermal growth factor receptor pathway substrate 8 (Eps8) is a novel regulator of cell adhesion and the blood-testis barrier integrity in the seminiferous epithelium

In the seminiferous epithelium, Eps8 is localized to actin-based cell junctions at the blood-testis barrier (BTB) and the apical ectoplasmic specialization (ES) in stage V-VI tubules but is considerably diminished in stage VIII tubules. Eps8 down-regulation coincides with the time of BTB restructuring and apical ES disassembly, implicating the role of Eps8 in cell adhesion. Its involvement in Sertoli-germ cell adhesion was substantiated in studies using an in vivo animal model by treating rats with 1-(2,4-dichlorobenzy)-1H-indazole-3-carbohydrazide (adjudin) to induce anchoring junction restructuring, during which Eps8 disappeared at the apical ES before germ cell departure. In Sertoli cell cultures with established permeability barrier mimicking the BTB in vivo, the knockdown of Eps8 by RNAi led to F-actin disorganization and the mislocalization of the tight junction proteins occludin and ZO-1, suggesting the function of Eps8 in maintaining BTB integrity. In vivo knockdown of Eps8 in the testis caused germ cell sloughing and BTB damage, concomitant with occludin mislocalization, further validating that Eps8 is a novel regulator of cell adhesion and BTB integrity in the seminiferous epithelium.

Cross-talk between tight and anchoring junctions-lesson from the testis

Spermatogenesis takes place in the seminiferous tubules in adult testes such as rats, in which developing germ cells must traverse the seminiferous epithelium while spermatogonia (2n, diploid) undergo mitotic and meiotic divisions, and differentiate into elongated spermatids (1n, haploid). It is conceivable that this event involves extensive junction restructuring particularly at the blood-testis barrier (BTB, a structure that segregates the seminiferous epithelium into the basal and the adluminal compartments) that occurs at stages VII-VIII of the seminiferous epithelial cycle. As such, cross-talk between tight (TJ) and anchoring junctions [e.g., basal ectoplasmic specialization (basal ES), adherens junction (AJ), desmosome-like junction (DJ)] at the BTB must occur to coordinate the transient opening of the BTB to facilitate preleptotene spermatocyte migration. Interestingly, while there are extensively restructuring at the BTB during the epithelial cycle, the immunological barrier function of the BTB must be maintained without disruption even transiently. Recent studies using the androgen suppression and Adjudin models have shown that anchoring junction restructuring that leads to germ cell loss from the seminiferous epithelium also promotes the production of AJ (e.g., basal ES) proteins (such as N-cadherins, catenins) at the BTB site. We postulate the testis is using a similar mechanism during spermatogenesis at stage VIII of the epithelial cycle that these induced basal ES proteins, likely form a "patch" surrounding the BTB, transiently maintain the BTB integrity while TJ is "opened", such as induced by TGF-b3 or TNFa, to facilitate preleptotene spermatocyte migration. However, in other stages of the epithelial cycle other than VII and VIII when the BTB remains "closed" (for approximately 10 days), anchoring junctions (e.g., AJ, DJ, and apical ES) restructuring continues to facilitate germ cell movement. Interestingly, the mechanism(s) that governs this communication between TJ and anchoring junction (e.g., basal ES and AJ) in the testis has remained obscure until recently. Herein, we provide a critical review based on the recently available data regarding the cross-talk between TJ and anchoring junction to allow simultaneous maintenance of the BTB and germ cell movement across the seminiferous epithelium.

Sterilization of male stray dogs with a single intratesticular injection of calcium chloride: a dose-dependent study

OBJECTIVE

To study a method of chemical sterilization and its efficacy in adult male stray dogs.

METHODS

Sterilization was performed 45 days after a single bilateral intratesticular injection of calcium chloride (CaCl(2)) at the doses of 5, 10, 15 or 20 mg per testis per kg body weight.

RESULTS

Histomorphological measures of testes showed total necrosis of testicular tissue at 45 days after an injection of either 10 or 15 or 20 mg CaCl(2) along with fibrosis and hyalinization in seminiferous tubules and interstitial spaces. Infiltration of leucocytes was also observed with the 10- or 15-mg dose. Disintegration of germ cell arrangement in seminiferous tubules and washing out of germ cells from the tubules were noted with the 5-mg dose. Relative organ weight, epididymal sperm count, plasma and intratesticular concentrations of testosterone, testicular activities of Delta(5),3beta-hydroxysteroid dehydrogenase (Delta(5),3beta-HSD), 17beta-hydroxysteroid dehydrogenase (17beta-HSD), glutathione peroxidase (GPx), glutathione S-transferase (GST) and superoxide dismutase (SOD) and testicular contents of glutathione (GSH) and glutathione disulphide (GSSG) and the ratio of GSH/GSSG, all were declined in each of the calcium chloride treated groups in comparison to the control group. Increases occurred in testicular malondialdehyde (MDA) and plasma concentrations of LH and FSH with each of the treatments by comparison with the control group. Plasma concentrations of cortisol, fasting blood sugar level, blood urea nitrogen as well as packed cell volume (PCV) and total plasma protein were recorded to monitor the changes in chronic stress in the experimental animals. Changes in these parameters were not significant.

CONCLUSION

An intratesticular injection of CaCl(2) at specified doses could be a suitable method of sterilization in preference to surgical castration of dogs.

Myotubularin phosphoinositide phosphatases, protein phosphatases, and kinases: their roles in junction dynamics and spermatogenesis

Spermatogenesis in the seminiferous epithelium of the mammalian testis is a dynamic cellular event. It involves extensive restructuring at the Sertoli-germ cell interface, permitting germ cells to traverse the epithelium from basal to adluminal compartment. As such, Sertoli-germ cell actin-based adherens junctions (AJ), such as ectoplasmic specializations (ES), must disassemble and reassemble to facilitate this event. Recent studies have shown that AJ dynamics are regulated by intricate interactions between AJ integral membrane proteins (e.g., cadherins, alpha6beta1 integrins and nectins), phosphatases, kinases, adaptors, and the underlying cytoskeleton network. For instance, the myotubularin (MTM) phosphoinositide (PI) phosphatases, such as MTM related protein 2 (MTMR2), can form a functional complex with c-Src (a non-receptor protein tyrosine kinase). In turn, this phosphatase/kinase complex associates with beta-catenin, a constituent of the N-cadherin/beta-catenin functional unit at the AJ site. This MTMR2-c-Src-beta-catenin complex apparently regulates the phosphorylation status of beta-catenin, which determines cell adhesive function conferred by the cadherin-catenin protein complex in the seminiferous epithelium. In this review, we discuss the current status of research on selected phosphatases and kinases, and how these proteins potentially interact with adaptors at AJ in the seminiferous epithelium to regulate cell adhesion in the testis. Specific research areas that are open for further investigation are also highlighted.

Evaluation of single intratesticular injection of calcium chloride for nonsurgical sterilization of male Black Bengal goats (Capra hircus): a dose-dependent study

This study describes the induction of chemosterilization in three groups each of six adult male Black Bengal goats at 30 days after a single bilateral intratesticular injection of a calcium chloride (CaCl(2), 2H(2)O) solution at the doses of 10, 20 or 40 mg/kg body weight/testis, always in a 2 ml volume of normal saline. Another one group of animals received only 2 ml of normal saline per testis as a control. The induction of chemosterilization was measured using relative testicular weight as well as histomorphological parameters including seminiferous tubular architecture and germ cell association in seminiferous tubules along with morphology of the interstitial space. Biochemical markers included activities of testicular Delta(5), 3beta-hydroxysteroid dehydrogenase (Delta(5), 3beta-HSD), 17beta-hydroxysteroid dehydrogenase (17beta-HSD), catalase, glutathione peroxidase (GPx), glutathione S-transferase (GST) and superoxide dismutase (SOD) as well as monitoring the level of testicular thiobarbituric acid reactive substances (TBARS), conjugated dienes and reduced glutathione (GSH) content along with plasma concentrations of testosterone, LH and FSH. Histomorphological measures of testes showed total necrosis of testicular tissue at 30 days after an injection of either 20 or 40 mg CaCl(2) along with fibrosis in seminiferous tubules and interstitial spaces. Infiltration of leucocytes was observed with the 40 mg dose. Disintegration of germ cell arrangement in seminiferous tubules and washing out of germ cells from the tubules were noted with the 10mg dose. Relative organ weights, plasma concentrations of testosterone, testicular activities of Delta(5), 3beta-HSD, 17beta-HSD, catalase, GPx, GST, and SOD and testicular contents of GSH all were declined. Increases occurred in testicular TBARS, conjugated dienes and plasma concentrations of LH and FSH with each of the treatments by comparison with the control group. Plasma concentrations of cortisol and fasting blood sugar level as well as packed cell volume (PCV) and total plasma protein were recorded to monitor the changes of chronic stress in the experimental animals. Changes in these parameters were not significant. An intratesticular injection of calcium chloride at specified doses could be a suitable method of sterilization in preference to surgical castration of goats.

Sertoli-Sertoli and Sertoli-germ cell interactions and their significance in germ cell movement in the seminiferous epithelium during spermatogenesis

Spermatogenesis is the process by which a single spermatogonium develops into 256 spermatozoa, one of which will fertilize the ovum. Since the 1950s when the stages of the epithelial cycle were first described, reproductive biologists have been in pursuit of one question: How can a spermatogonium traverse the epithelium, while at the same time differentiating into elongate spermatids that remain attached to the Sertoli cell throughout their development? Although it was generally agreed upon that junction restructuring was involved, at that time the types of junctions present in the testis were not even discerned. Today, it is known that tight, anchoring, and gap junctions are found in the testis. The testis also has two unique anchoring junction types, the ectoplasmic specialization and tubulobulbar complex. However, attention has recently shifted on identifying the regulatory molecules that "open" and "close" junctions, because this information will be useful in elucidating the mechanism of germ cell movement. For instance, cytokines have been shown to induce Sertoli cell tight junction disassembly by shutting down the production of tight junction proteins. Other factors such as proteases, protease inhibitors, GTPases, kinases, and phosphatases also come into play. In this review, we focus on this cellular phenomenon, recapping recent developments in the field.

Sertoli cell tight junction dynamics: their regulation during spermatogenesis

During spermatogenesis, developing preleptotene and leptotene spermatocytes must translocate from the basal to the adluminal compartment of the seminiferous epithelium so that fully developed spermatids (spermatozoa) can be released to the tubular lumen at spermiation. It is conceivable that the opening and closing of the inter-Sertoli tight junctions (TJs) that constitute the blood-testis barrier are regulated by an array of intriguingly coordinated signaling pathways and molecules. Several molecules have been shown to regulate Sertoli cell TJ dynamics; they include, for example, transforming growth factor beta3 (TGFbeta3), occludin, protein kinase A, protein kinase C, and signaling pathways such as the TGFbeta3/p38 mitogen-activated protein kinase pathway. Yet the mechanisms that regulate these events are essentially not known. This minireview summarizes some of the recent advances in the study of TJ dynamics in the testis and reviews several models that can be used to study TJ dynamics. It also highlights specific areas for future research toward understanding the precise physiological relationship between junction dynamics and spermatogenesis.

Ectoplasmic specializations in the Sertoli cell: new vistas based on genetic defects and testicular toxicology

Abstract The ectoplasmic specialization is a unique junctional complex formed in two cortical areas of the Sertoli cell in the mammalian testis: one near the base of the seminiferous epithelium forming the blood-testis barrier, and the other near the lumen of the seminiferous tubule embracing the acrosome region of the developing spermatids. The specialization consists of the Sertoli cell plasma membrane, a subsurface cistern of the endoplasmic reticulum and a layer of closely packed actin filaments that is sandwiched between the plasma membrane and the subsurface cistern. No functions of the specializations other than the blood-testis barrier have been established. However, over the past decade, knowledge about the ectoplasmic specialization has been steadily accumulating and, in particular, there has been a tremendous increase in knowledge based on molecular biological approaches to specialization-associated proteins, including tight junction-associated proteins, based on phenotype analyses of gene-knockout mice and mutant animals, and based on analyses of the effects of exogenous estrogens, so-called endocrine disruptors. Progress in studies on the ectoplasmic specialization will facilitate the elucidation of numerous important questions regarding spermatogenesis, including the pathogenesis of azoospermia and the mechanisms of action of endocrine disruptors.

Dose-dependent response to an intratesticular injection of calcium chloride for induction of chemosterilization in adult albino rats

This study concerned the minimum and optimum effective doses of calcium chloride needed for induction of chemosterilization in male albino rats, 30 days after a single intratesticular injection of calcium chloride (CaCl2.2H2O) solution at 2.5, 5, 10 or 20 mg per 100 g body weight per testis. There was a significant diminution in the relative wet weight of the sex organs (p<0.01), epididymal sperm count (p<0.001), plasma concentration of testosterone (p<0.01), testicular activities of delta5,3beta-hydroxy steroid dehydrogenase (delta5,3beta-HSD), 17beta-hydroxy steroid dehydrogenase (17beta-HSD) (p<0.01), glutathione S-transferase (GST) (p<0.01), superoxide dismutase (SOD) (p<0.01), and peroxidase (p<0.01), significant elevations in testicular content of malondialdehyde (MDA) and conjugated dienes (p<0.01), along with derangement of seminiferous tubular architecture and degeneration of the Leydig cells in the testis and elevations in the concentrations in the plasma of LH and FSH (p<0.01), commencing at a dose of 5 mg, with the greatest effects at a dose of 20 mg. No significant alterations in these factors occurred at the dose of 2.5 mg in comparison to the control that received only the vehicle. There was no significant alteration in the plasma concentrations of prolactin (p>0.05), corticosterone (p>0.05) or fasting blood glucose or in the rectal temperature (p>0.05) at any of the doses relative to the control group, suggesting that this chemosterilizing procedure did not exert any chronic stress on the experimental animals. From these observations, it may be suggested that 5 mg should be considered as the minimum dose, and 10 mg or 20 mg as the optimum dose, whereas 2.5 mg was ineffective for induction of chemosterilization. There would seem to be little point in using more than 20 mg of calcium chloride for this purpose. Intratesticular injection of calcium chloride at an effective dose may be considered as an alternative to surgical castration.

Glycerol suppresses proliferation of rat hepatocytes and human HepG2 cells

BACKGROUND

In fulminant hepatic failure (FHF), the ability of surviving hepatocytes to proliferate is diminished. Therefore, it is important that medical therapy cause no further impairment of liver regeneration. In FHF, intracranial hypertension secondary to brain edema is the most common cause of brain injury and death and glycerol is used in some countries to treat this complication. Glycerol has been long known to suppress the growth of various cell types. We therefore decided to examine the effect of glycerol on hepatocyte proliferation in vitro and in vivo in rats subjected to partial (2/3) hepatectomy. Additionally, we investigated the effect of glycerol on the proliferation of HepG2 cells.

MATERIALS AND METHODS

Mitogen-induced primary rat hepatocytes were cultured in a hormonally defined Dulbecco's modified Eagle's medium containing increasing amounts of glycerol (0.5, 1.0, 2.0, 4.0%). HepG2 cells were cultured in minimal essential medium/10% FBS. After 2 days, HepG2 cells were exposed to glycerol (1.0-2.0-4.0%) and harvested after 48 h. Control dishes contained no glycerol. Cell proliferation was measured by the incorporation of [(3)H]thymidine and/or bromodeoxyuridine (BrdU). In vivo, Sprague-Dawley rats were subjected to standard partial 2/3 hepatectomy and assigned to intraportal administration of either 400 microl of glycerol or saline. Rats were killed after 1, 2, 3, 5, and 7 days. Liver weight/body weight ratio and BrdU uptake were measured.

RESULTS

In all cultures tested, glycerol suppressed the growth of cells in a dose-dependent manner. In vivo, a single intraportal dose of glycerol slowed the liver regenerative response.

CONCLUSIONS

This study demonstrated that glycerol has a potent growth-inhibitory effect on hepatocyte proliferation in vivo and in vitro. Remarkably, glycerol inhibited the proliferation of liver cancer cells as well. The results of this study have important clinical implications.

Cell Junction Dynamics in the Testis: Sertoli-Germ Cell Interactions and Male Contraceptive Development

Spermatogenesis is an intriguing but complicated biological process. However, many studies since the 1960s have focused either on the hormonal events of the hypothalamus-pituitary-testicular axis or morphological events that take place in the seminiferous epithelium. Recent advances in biochemistry, cell biology, and molecular biology have shifted attention to understanding some of the key events that regulate spermatogenesis, such as germ cell apoptosis, cell cycle regulation, Sertoli-germ cell communication, and junction dynamics. In this review, we discuss the physiology and biology of junction dynamics in the testis, in particular how these events affect interactions of Sertoli and germ cells in the seminiferous epithelium behind the blood-testis barrier. We also discuss how these events regulate the opening and closing of the blood-testis barrier to permit the timely passage of preleptotene and leptotene spermatocytes across the blood-testis barrier. This is physiologically important since developing germ cells must translocate across the blood-testis barrier as well as traverse the seminiferous epithelium during their development. We also discuss several available in vitro and in vivo models that can be used to study Sertoli-germ cell anchoring junctions and Sertoli-Sertoli tight junctions. An in-depth survey in this subject has also identified several potential targets to be tackled to perturb spermatogenesis, which will likely lead to the development of novel male contraceptives.

Testicular effect of mustard gas

OBJECTIVES

To explain the testicular effect of mustard gas.

METHODS

Eighty-one patients who had been exposed to sulfur mustard and had the presenting symptom of infertility underwent evaluation of their reproductive system. Three semen analyses, serum hormonal determinations (luteinizing hormone, follicle-stimulating hormone, and testosterone), and genital examinations were completed for all patients, as were testicular biopsies in 24 patients.

RESULTS

Azoospermia and severe oligospermia were diagnosed in 42.5% and 57.5% of patients, respectively. Hormone studies revealed an elevated plasma follicle-stimulating hormone level and normal plasma luteinizing hormone and testosterone concentrations. Testicular biopsy showed selective atrophy of the germinal epithelium, intact Sertoli cells, and normal-appearing Leydig cells.

CONCLUSIONS

Mustard gas can cause defective spermatogenesis years after exposure.

Evaluation of intratesticular injection of glycerol for nonsurgical sterilization of dogs

OBJECTIVE

To determine efficacy of intratesticular injection of glycerol as a means to sterilize dogs.

ANIMALS

Six 2- to 4-year-old sexually intact male dogs.

PROCEDURE

Testicular volume, serum testosterone concentration, and number of sperm in ejaculate were determined before and at weekly intervals for 12 weeks following intratesticular injection of a 70% glycerol solution (1 ml/testis). Testicular tissue specimens for histologic evaluation were obtained 4, 8, and 12 weeks following injection.

RESULTS

Number of sperm in ejaculate following glycerol injection was not significantly different from number before injection. Compared with preinjection values, serum testosterone concentrations were significantly less 5, 9, and 10 weeks following injection, although libido and ejaculate characteristics were unchanged. Testicular swelling was evident 24 to 48 hours following injection, and testicular volume decreased starting on week 5 following treatment. Seminiferous tubules and evidence of normal spermatogenesis were detected in testicular biopsy specimens obtained from all dogs 12 weeks following injection.

CONCLUSION AND CLINICAL RELEVANCE

Intratesticular injection of a 70% glycerol solution did not result in azoospermia and sterility in dogs.

A radioimmunoassay for the regulatory allylic steroid, 3 alpha-hydroxy-4-pregnen-20-one (3 alpha HP)

The allylic steroid, 3 alpha-hydroxy-4-pregnen-20-one (3 alpha HP), found in gonadal and brain tissues by radiotracer and chemical methods, had been shown to play a role in gametogenesis, gonadotropin secretion and brain excitability. Since no simple assay was available, a radioimmunoassay for 3 alpha HP was developed using [3H]3 alpha HP and an antiserum raised against 3 alpha HP-20-CMO conjugated to bovine serum albumin. The specificity of the assay for the 3 alpha allylic configuration of 3 alpha HP was confirmed by examining 32 other steroids; cross-reaction with steroids containing different configurations (including metabolites of 3 alpha HP such as progesterone) was less than 0.9%. A Scatchard plot indicated a Ka of 1.56 X 10(9) M-1. Inter- and intra-assay coefficients of variation were 13.1 and 4.5%, respectively. The sensitivity of the assay was 6 pg and the 50% intercept of the standard curve was approx. 123 pg. The measurement by RIA of 3 alpha HP from standard solutions and HPLC purified tissue extracts was confirmed qualitatively and quantitatively by GC/MS methods. The RIA method was employed to determine 3 alpha HP levels in cultured Sertoli cells and in serum of intact and ovariectomized adult rats. Although for most uses, chromatography would not be necessary, two possible methods are presented to enable the separation of 3 alpha HP from other interfering steroids prior to RIA.

Inhibition of cell proliferation by glycerol

The effect of glycerol on proliferation of BHK, CHO, HBL, MCF-7, and human glioma cells was studied. Cell proliferation was significantly decreased in all the cell lines at glycerol concentrations of 2-4% in the culture medium. The inhibition was dose-dependent, complete suppression of proliferation occurring at a glycerol concentration of 4% for the MCF-7 cell line and 6-8% for the BHK, CHO and human glioma cells. Studies on [3H]thymidine incorporation correlate with the effect on cell proliferation. The viability of the cells was not significantly affected until higher concentrations of glycerol (12% +) were present. Recovery studies with BHK cells indicated that replacement of the glycerol medium with glycerol-free medium resulted in full recovery following exposure to 4% glycerol and only partial recovery (65%) of proliferation rate following exposure to 10-12% glycerol. It is concluded that glycerol, a substance that is normally present in tissues, can serve as a potent inhibitor of cell proliferation.