Insights into testicular damage induced by ethinylestradiol in rats

Culture-space control is effective in promoting haploid cell formation and spermiogenesis in vitro in neonatal mice

The classical organ culture method, in which tissue is placed at the gas‒liquid interphase, is effective at inducing mouse spermatogenesis. However, due to reginal variations in the supply of oxygen and nutrients within a tissue, the progress of spermatogenesis was observed only in limited areas of a tissue. In addition, haploid cell formation and its differentiation to spermatozoon, i.e. spermiogenesis, were infrequent and inefficient. Here, we show that the polydimethylsiloxane (PDMS)-chip ceiling (PC) method, which ensures a uniform supply of nutrients and oxygen throughout the tissue by pressing it into a thin, flat shape, can provide control over the culture space. We used this method to culture testis tissue from neonatal mice, aged 1 to 4 days, and found that modulating the culture space during the experiment by replacing one chip with another that had a higher ceiling effectively increased tissue growth. This adjustment also induced more efficient spermatogenesis, with the process of spermiogenesis being particularly promoted. Meiotic cells were observed from culture day 14 onward, and haploid cells were confirmed at the end of each experiment. This technique was also shown to be a sensitive assay for testicular toxicity. Culture-space control will be a critical regulation parameter for sophisticated tissue culture experiments.

Metabolomics-based pathway changes in testis fragments treated with ethinylestradiol in vitro

BACKGROUND

There is a need to develop in vitro models to test drugs and chemicals that induce toxicity in the male reproductive system. We have evaluated an in vitro mouse testis organ culture model capable of producing viable, fertilization-proven sperm as a possible toxicity test model. Although this in vitro model was limited to round spermatid differentiation, histopathology observations could still be performed. Liquid chromatography/mass spectrometry analysis (LC/MS)-based metabolomics was used to measure metabolome changes of chemically treated in vitro testis fragments.

METHODS

On Postnatal Day 5, C57BL/6J mouse testes were divided into four fragments, which were placed onto a 1.5% agarose gel cube and cultured in α-MEM including 0.4% AlbuMAX I (Day 0). On Day 1 of culture, testis fragments were treated with 0 (control), 0.01, or 1 nM ethinylestradiol (EE). On Day 20 of culture, the testis fragments were collected for LC/MS and histology analysis.

RESULTS

Several metabolites involved in glycogen metabolism and glycolysis pathways (uridine diphosphate-glucose, glucose phosphate, and pyruvate), in the tricarboxylic acid cycle pathway (oxaloacetate and aspartate), and in the arginine and proline metabolism (arginine and spermine) were significantly altered in the 1 nM EE treated group compared to the control group. The metabolite changes were associated with an increase in percentage of seminiferous tubules with round spermatids as well as dose-dependent dead cells.

CONCLUSION

These findings suggest that EE treatment may cause testicular toxicity by affecting glycogen metabolism and energy pathways. To confirm these findings, further experiments will be necessary using other testicular toxicants.

Gene expression profiling of cultured mouse testis fragments treated with ethinylestradiol

The assessment of xenobiotic-induced testicular toxicity is important in drug development. Nonetheless, in vitro models to test drugs and chemicals that may cause testicular toxicity are lacking, requiring the continued use of animal models for those studies. We previously evaluated an in vitro mouse testis organ culture system using ethinylestradiol (EE), a well-studied testicular toxicant, and demonstrated a dose-dependent relationship between adverse effects to germ cell differentiation and increasing EE concentrations. However, we terminated that study after 20 days of culture due to oxygen deficiency during germ cell differentiation. Therefore, in the current study, we aimed to identify gene(s) with potential for supporting the histopathological evaluations of testicular toxicity using in vitro testis organ culture system. We cultured testis fragments obtained from mice at postnatal day (PND) 5 in α-Minimal Essential Medium containing 40 mg/mL AlbuMAX^™ I and treated them with 0.01 or 1 nM EE on day 1 of culture. On day 20, we collected testis fragments for RNA sequencing analysis and quantitative polymerase chain reaction (qPCR). We found that phospholipase C, zeta 1 and testis-specific serine kinase 4 genes, that are involved in spermatogenesis and predominantly expressed in the testis, were significantly reduced in testis fragments treated with the highest concentration of EE. Also, cytochrome P450, family 26, subfamily b, polypeptide 1 (Cyp26b1) and interleukin 16 (Il16) were up-regulated in the highest EE-treated groups. Further studies are needed to confirm the variations of these gene expression using other testicular toxicants.

Evaluation of an in vitro mouse testis organ culture system for assessing male reproductive toxicity

BACKGROUND

Development of an in vitro system capable of producing mature sperm remains a challenging goal, with only few successes reported. Such a system, could be used to test agents for potential toxicity to the male reproductive system; to explore this, we exposed immature mouse testis fragments in culture to ethinylestradiol (EE), a well-known testicular toxicant in vivo.

METHODS

Testis fragments from postnatal day 5 mice were cultured in Albumax I medium. After 24 hr of culture, fragments were treated with 0.01, 0.1 or 1 nM EE, then harvested after 20 days in culture and examined for histology or gene expression measures by quantitative PCR.

RESULTS

There was substantial variability between fragments in the degree of spermatogenesis observed. The percentage of seminiferous tubules containing any dead germ cells increased as a result of EE exposure in a dose dependent fashion. This was accompanied with a decreased percentage of tubules with round spermatids. Expression of estrogen receptor 1, cytochrome P450, family 11, subfamily a, and polypeptide 1 also was reduced, depending on the dose.

CONCLUSION

These gene expression changes in the testis fragments are similar to those seen after animals have been exposed to EE. Gene expression changes in testis fragments are encouraging, but the variability across samples will need to be reduced for this in vitro system to become a generally applicable method for assessing testicular toxicants.

Neonatal exposure to ethinylestradiol increases ventral prostate growth and promotes epithelial hyperplasia and inflammation in adult male gerbils

The aim of this study was to analyse morphologically the ventral prostate of adult Mongolian gerbils exposed to ethinylestradiol (EE) during the first week of postnatal development. Lactating females received daily, by gavage, doses of 10 μg/kg of EE diluted in 100 μl of mineral oil from the 1st to 10th postnatal day of the pups (EE group). In the control group (C), the lactating females received only the vehicle. Upon completing 120 days of age, the male offspring were euthanized and the prostates collected for analyses. We employed morphological, stereological-morphometrical, immunohistochemical and ultrastructural methods. The results showed that the postnatal exposure to EE doubled the prostatic complex weight, increasing the epithelial and stromal compartments, in addition to the secretory activity of the ventral lobe of the prostate. All glands exposed to EE showed strong stromal remodelling, and some foci of epithelial hyperplasia and inflammatory infiltrate in both luminal and epithelial or stromal compartments. Cells positive for anti-AR and anti-PCNA reactions increased into the epithelial and stromal tissues. ERα-positive cells, which are normally found in the stromal compartment of intact prostates, were frequently observed in the prostatic epithelium of treated animals. This study demonstrated that the exposure to EE during postnatal development causes histophysiological alterations in this gland, predisposing to the development of prostatic lesions during life. These results are important for public health, considering that women worldwide have commonly used EE. Moreover, the bioaccumulation of this chemical has increased in different ecosystems.

Biphasic effect of Syzygium aromaticum flower bud on reproductive physiology of male mice

The flower buds of Syzygium aromaticum (clove) have been used for the treatment of male sexual disorders in indigenous medicines of Indian subcontinent. Therefore to evaluate the efficacy of Syzygium aromaticum on the male reproductive health, chronic oral exposure of aqueous extract of flower buds of Syzygium in three doses (15 mg, 30 mg and 60 mg kg^-1 BW) were studied for a single spermatogenic cycle (35 days) in Parkes (P) strain mice. Lower dose (15 mg) of Syzygium aromaticum flower buds increased serum testosterone level and testicular hydroxysteroid dehydrogenase (HSD) activities and improved sperm motility, sperm morphology, secretory activity of epididymis and seminal vesicle, and number of litters per female. On the other hand, higher doses (30 and 60 mg) of the treatment adversely affected above parameters. Further, higher doses of the extract also had adverse effects on daily sperm production, 1C cell population and on histology of testis. In conclusion, Syzygium aromaticum flower buds extract exhibits biphasic effect on reproductive physiology of male mice. Lower dose of Syzygium aromaticum flower bud extract is androgenic in nature and may have a viable future as an indigenous sexual rejuvenator, while higher doses adversely affected functional physiology of reproductive organs.

Exposure to leachate from municipal battery recycling site: implication as key inhibitor of steroidogenic enzymes and risk factor of prostate damage in rats

Few or no studies have measured the effect of short- and long-term exposure to industrial leachate. Mature male Wistar strain albino rats (175-220 g) underwent sub-chronic exposure to leachate from the Elewi Odo municipal battery recycling site (EOMABRL) via oral administration for a period of 60 days at different doses (20%, 40%, 60%, 80%, and 100%) per kilogram of body weight to evaluate the toxic effects of the leachate on male reproductive function using steroidogenic enzymes and biomarkers of prostate damage. Control groups were treated equally but were given distilled water instead of the leachate. After the treatment periods, results showed that the treatment induced systemic toxicity at the doses tested by causing a significant (p<0.05) loss in absolute body weight and decline in growth rate. There was a marked significant decrease (p<0.05) in testicular activities of Δ(5)-3β-hydroxysteroid dehydrogenase and 17β-hydroxysteroid dehydrogenase. Conversely, the activity of prostatic acid phosphatase, a key marker enzyme for prostrate damage was significantly (p<0.05) elevated in the treated rats. Similarly, the administration of EOMABRL significantly (p<0.05) exacerbated the activity of total acid phosphatase with concomitant increase in the activity of prostatic alkaline phosphatase. These findings conclude that exposure to leachate from a battery recycling site induces sub-chronic testicular toxicity by inhibiting key steroidogenic enzymes and activating key markers linked with prostate damage/cancer in rats.

Histopathological and immunohistochemical changes in the testes of rabbits after injection with the growth promoter boldenone

Recently, boldenone (androgenic steroid) is used in improvement of the growth and food conversion in food-producing animals. In addition, it is used by bodybuilders during both off-season and precontest, where it is well known for increasing vascularity while preparing for a bodybuilding contest. The present study was designed to investigate the possible effect of growth promoter boldenone undecylenate on the structure and functions of rabbit testes. A total of 32 adult New Zealand rabbits were divided into 4 groups. The first group in the control group includes animals that were intramuscularly injected with olive oil and dissected after 3 weeks. Three experimental groups include animals that receive 1, 2, and 3 intramuscular injections of 5 mg/kg body weight boldenone, and dissected after 3, 6, and 9 weeks, respectively. Treating rabbits with boldenone increased the testosterone levels compared to the control group. Seminiferous tubules of the rabbit testis treated with boldenone showed reduced development and degeneration of the germinal epithelium, leading to debris and syncytial cell formation in the lumina of seminiferous tubules. Our immunohistochemical results indicated severe reduction in proliferating cell nuclear antigen-positive spermatogonia in boldenone-treated animals as compared to the control group. These findings explain the common phenomena among athletics and bodybuilders who suffer from infertility as they were injected with some drugs such as steroids (boldenone) to build muscles.

Safety assessment of Syzygium aromaticum flower bud (clove) extract with respect to testicular function in mice

The flower buds of Syzygium aromaticum (clove), a common food flavor, have been used as indigenous medicine for the treatment of male sexual disorders in Asian countries. However, the possible mechanism(s) by which it acts at testicular level remain obscure. Therefore, to investigate its effect on testicular function, chronic oral exposure of hexane extract of flower buds of Syzygium aromaticum in three doses (15 mg, 30 mg, and 60 mg/kg BW) were evaluated for a single spermatogenic cycle (35 days) in Parkes (P) strain mice. The treatment did not induce systemic toxicity at the doses tested. Lower dose (15 mg) of the extract increased the activities of Delta(5) 3 beta-HSD and 17 beta-HSD, and serum level of testosterone. The higher doses (30 and 60 mg) of extract inhibited these parameters and induced non-uniform degenerative changes in the seminiferous tubules associated with decrease in daily sperm production and depletion of 1C (round and elongated spermatids) population. Taken together these results suggest biphasic action of hexane extract of Syzygium aromaticum flower bud on testicular function, thereby advocating a cautious use of the flower bud as an aphrodisiac in indigenous systems of medicine in Asian countries.