Katarzyna Marchlewska

Triiodothyronine modulates initiation of spermatogenesis in rats depending on treatment timing and blood level of the hormone

Triiodothyronine (T3) stimulates spermatogenic onset but the influence of T3 on spermatogonia development is unknown. The aim of the study was to investigate the role of T3 for both processes simultaneously. Male rats were given daily injections of 100 μg T3/kg body weight or vehicle from birth until postnatal day (pnd) 5 and euthanized on pnd 6 (short T3-sT3). Other rats, euthanized on pnd 16, were treated either transiently with T3 (tT3) during the initial 5 days or continuously until pnd 15 (cT3). sT3 was found to increase gonocyte differentiation, spermatogonia number, cell degeneration and proliferation. tT3 increased serum T3 level and spermatogonial development to adult values precociously, but cell degeneration or proliferation were not affected. cT3 increased serum T3 together with cell degeneration and proliferation, but cell number was not affected. In conclusion, T3 may modulate spermatogonial development quantitatively depending on treatment timing and blood level of the hormone.

Role of FSH and triiodothyronine in Sertoli cell development expressed by formation of connexin 43-based gap junctions

Follicle-stimulating hormone (FSH) and triiodothyronine (T3) are known regulatory factors of spermatogenesis initiation. Connexin 43 (Cx43) is the most ubiquitous constitutive protein of gap junctions in the testis. This study evaluates the effects of the hyperstimulation of FSH and T3 during testicular maturation on Cx43 expression in the testis. The newborn, male Wistar rats were divided randomly into four experimental groups: FSH group-daily injections of FSH 7.5 IU/animal; T3 group-100 µg T3/kg body weight; FSH+T3 group-both substances; A control group-received vehicles in the same volume. Proliferating cell nuclear antigen immunohistochemistry and toluidine blue staining were used to determine the germ cell proliferation and degeneration. Cx43 immunolocalization was evaluated to find Cx43 maturational changes. Under FSH treatment, the proliferation rate was high so the total number of Sertoli cells increased with a low level of degeneration and lumen formation. T3 stimulation evoked a reduction in the proliferation rate and a decrease in Sertoli cell number but with intensive formation of lumen. T3+FSH inhibited the proliferation rate and stimulated lumen formation together with degeneration, which negatively influenced the number of germ cells in the seminiferous epithelium. We conclude that T3 action seems to be particularly connected with the maturation of Cx43 gap junctions. FSH stimulates maturation of Sertoli cell function, but this effect may take place regardless of the presence of Cx43-dependent intercellular communication. The hyperstimulation of both FSH and T3 damages Cx43 connections and hence evokes regressional changes in the seminiferous epithelium.

Xenoestrogens diethylstilbestrol and zearalenone negatively influence pubertal rat's testis.

UNLABELLED The aim of this study was to assess the impact of xenoestrogens: diethylstilbestrol (DES) and zearalenone (ZEA) on rats pubertal testis and to compare it with the effect of natural estrogen - 17beta-estradiol (E). Male Wistar rats were daily, subcutaneously injected at 5th-15th postnatal days (p.d.) with E (1.25 or 12.5 mug) or DES (1.25 or 12.5 mug) or ZEA (4 or 40 mug) or vehicle. At 16th p.d. testes were dissected, weighted, and paraffin embedded. Following parameters were assessed: diameter and length of seminiferous tubule, numbers of spermatogonia A+intermediate+B (A/In/B), preleptotene spermatocytes (PL), leptotene+zygotene+pachytene spermatocytes (L/Z/PA) and Sertoli cells per testis. Testes weight, seminiferous tubule diameter and length were decreased by both doses of E, DES and ZEA. DES effect was the strongest, but its influence on testis weight and seminiferous tubule length, on the contrary to E and ZEA, was not dose-dependent. Similarly, DES in both doses had the most severe negative impact on the number of germ and Sertoli cells. The negative influence of E on germ cells was less pronounced. The negative effect of ZEA was seen only after administration of the higher dose on spermatogonia number, while DES and E decreased A/In/B number more evidently. Sertoli cell number were decreased after both doses of E. ZEA40 decreased Sertoli cell number while ZEA4 had no effect. CONCLUSION exposure of prepubertal male rat to DES has the strongest detrimental effect on the developing testis in comparison to E and ZEA. Both, E and DES, decreased number of germ and Sertoli cells, diminished seminiferous tubule diameter, length and testis weight. ZEA had much more weaker effect than the potent estrogens.

Testosterone and oestradiol in concert protect seminiferous tubule maturation against inhibition by GnRH-antagonist

Oestradiol enhances follicle stimulating hormone (FSH) action on seminiferous tubule maturation, but the relative involvement of oestradiol and testosterone remains unclear. This study compares the influences of oestrogen and androgen in FSH and testosterone-deficient rats. Animals were injected daily GnRH-antagonist alone (Ant) or combined with 17β-oestradiol benzoate (EB), or testosterone propionate (TP), or both from post-natal day (pnd) 5 to 15. Hormone levels, tubule growth, cell numbers, germ cell apoptosis and proliferation, and Sertoli cell maturation were evaluated on pnd 16. Ant decreased serum FSH and testosterone levels to ∼60% and ∼50% of control values, respectively, and decreased tubule growth, Sertoli cell number and maturation. Germ cell number declined by apoptosis. Co-administration of EB stimulated spermatogonia proliferation and maintained FSH levels (86% of control). Tubule growth, Sertoli cell number and spermatocyte apoptosis remained normal after TP co-administration, but Sertoli cell maturation, germ cell number and spermatogonia survival were reduced. Co-administration of EB with TP prevented all inhibitions. In conclusion, administration of oestradiol with testosterone, but neither one alone, protected seminiferous tubule maturation against inhibition caused by Ant-induced disruption. Oestrogen was involved in stimulating germ cell proliferation and the maintenance of Sertoli cell maturation, whereas androgen affected seminiferous tubule growth and spermatocyte survival.

Less advanced testicular dysgenesis is associated by a higher prevalence of germ cell neoplasia

There is a theory that the more evident clinical signs of testicular dysgenesis, the more frequent the neoplastic lesions are. The aim of this study was to relate the incidence of testicular germ cell neoplastic lesions (overt germ cell tumours--GCT or testicular carcinoma in situ) to the intensity of testicular organogenesis disturbances (dysgenesis). Biopsies were taken from 154 testes of the following patients: 23 patients with GCT in the contralateral gonad (CGCT), 41 patients with undescended testes operated in childhood (UDT), 90 with azoo-/oligozoospermia (A/O) diagnosed because of infertility. Assessment of seminiferous epithelium, number of Leydig cells, areal fraction of intertubular space (IS), morphometric analysis of seminiferous tubules diameter and thickness of tubular wall were performed. Monoclonal antibodies against placental like alkaline phosphatase and cytokeratin 18 were applied. Germ cell neoplastic lesions were detected in 7.1% of testes and were associated with disturbed spermatogenesis. Among testes with disturbed spermatogenesis they were found the most frequently in CGCT (22.2% vs. 11.1% in UDT and 3.8% in A/O), where spermatogenesis had the highest score (5.7 +/- 3.8 points vs. 4.2 +/- 2.7 in UDT and 4.6 +/- 2.9 in A/O). In CGCT, signs of testicular dysgenesis were less advanced: the highest tubular diameter was 164.4 +/- 32.3 microm vs. 163.5 +/- 28.6 in UDT and 161.4 +/- 31.5 in A/O, the lowest thickness of tubular wall was 8.9 +/- 3.2 microm vs. 10.2 +/- 3.6 in UDT and 10.2 +/- 3.2 in A/O, lowest IS was 36.9 +/- 14.9% vs. 47.9 +/- 18.0 in UDT and 46.5 +/- 18.5 in A/O, and the lowest percentage of tubules with immature Sertoli cells was 0.1 +/- 0.4% vs. 4.9 +/- 7.0 in UDT and 5.2 +/- 9.7 in A/O. Results indicate that neoplastic lesions appear only in testes with disturbed spermatogenesis. Worse condition of spermatogenesis is associated by the presence of other dysgenetic features, but neoplastic lesions appear more frequently in testes with the less advanced features of testicular dysgenesis.

Presence of aerobic micro-organisms and their influence on basic semen parameters in infertile men.

Urogenital tract infections in males are one of the significant etiological factors in infertility. In this prospective study, 72 patients with abnormal semen parameters or any other symptoms of urogenital tract infection were examined. Semen analysis according to the WHO 2010 manual was performed together with microbial assessment: aerobic bacteria culture, Chlamydia antigen test, Candida culture, Ureaplasma and Mycoplasma‐specific culture. In total, 69.4% of semen samples were positive for at least one micro‐organism. Ureaplasma sp. was the most common micro‐organism found in 33% of semen samples of infertile patients with suspected male genital tract infection. The 2nd most common micro‐organisms were Enterococcus faecalis (12.5%) and Escherichia coli (12.5%), followed by Staphylococcus aureus (7%), Chlamydia trachomatis (7%) and Candida sp. (5.6%). Generally, bacteria were sensitive to at least one of the antibiotics tested. No statistically significant relationship was observed between the presence of aerobic micro‐organisms in semen and basic semen parameters: volume, pH, concentration, total count, motility, vitality and morphology.

Maturational changes in connexin 43 expression in the seminiferous tubules may depend on thyroid hormone action.

Introduction Connexin 43 (Cx43) mediates the effect of thyroid hormone on Sertoli cell maturation in vitro. We investigated the influence of triiodothyronine (T3) administration on Cx43 expression in relation to the progress in seminiferous tubule maturation. Material and methods Male rats were daily injected with 100 µg T3/kg body weight from birth until postnatal day (pnd) 5 (transient treatment – tT3) or until pnd 15 (continuous treatment – cT3) or solvent – control (C). On pnd 16 serum hormone levels, body and testes weight, seminiferous tubule morphometry, Cx43 immunostaining and germ cell degeneration were investigated. Cx43 expression was also assessed in six 50-day-old adult untreated rats. Result tT3 increased 2.6-fold serum level of T3, testes weight, and seminiferous tubule diameter, and induced maturation-like dislocation of Cx43 expression from the apical to the peripheral region of Sertoli cell cytoplasm. In addition, incidence of Cx43-positive tubules declined from 86% in C to 46% after tT3, being similar to the adult value (30% of tubules Cx43-positive). In turn, cT3 increased serum T3 level 12-fold, and decreased body weight. Seminiferous tubules became shortened and distended, Sertoli cell cytoplasm vacuolated, Cx43 expression had minimal intensity and germ cell degeneration increased. Conclusions Cx43 might intermediate a short and transient stimulatory effect of T3 on seminiferous tubule maturation that disappeared together with exposure to the toxic effect of a continuously high level of the hormone.

Di(n-butyl) phthalate has no effect on the rat prepubertal testis despite its estrogenic activity in vitro

The aim of this study was to assess the impact of di(n-butyl) phthalate (DBP) on the rats prepubertal testis. Male Wistar rats were given daily subcutaneous injections with DBP (20 or 200 μg) or a vehicle from the 5th to the 15th postnatal day (pd). On the 16(th) pd, the rats were euthanized, and the testes were dissected, weighed, and paraffin embedded. The blood was collected to determine the serum levels of testosterone (T), estradiol (E) and FSH. The following parameters were assessed in the testis sections: diameter and length of seminiferous tubules (st), numbers of spermatogonia A + intermediate + B (A/In/B), preleptotene spermatocytes (PL), leptotene + zygotene + pachytene spermatocytes (L/Z/PA) and Sertoli cells per testis, percentage of st containing gonocytes or pachytene spermatocytes or lumen. An estrogenicity in vitro test was performed by means of a transgenic yeast strain expressing human estrogen receptor alpha. At both doses, DBP had no influence on testis and seminal vesicle weight, st diameter and length, number of germ and Sertoli cells per testis, percentage of st containing gonocytes or pachytene spermatocytes or lumen. DBP did not change E, T or FSH serum levels. The in vitro yeast screen showed that DBP was a weak estrogenic compound, approximately six to seven orders of magnitude less potent than 17β-estradiol. In conclusion, exposure of a rat to DBP in doses 100 or 1,000-fold higher than a Tolerable Daily Intake for humans had no effect on its testicular development.

Administration of testosterone inhibits initiation of seminal tubule growth and decreases Sertoli cell number in the earliest period of rat's postnatal development.

UNLABELLED Sertoli cell (SC) number determines testes size and their capacity to produce spermatozoa. In the rat SC proliferate until 15th postnatal day (PND). Their proliferation is stimulated by FSH and inhibited by estradiol, but the role for androgens is uncertain. In this study we analyzed the effects of testosterone administration on testes growth and SC number in relation to timing of the treatment. Male rats were injected with 2.5 mg of testosterone propionate (TP) from birth until 5th PND and autopsied either on 6th PND [TP1-5(6)] or on 16th PND [TP1-5(16)] (transient administration). Other rats received TP from birth until 15th PND [TP1-15] or between 5th and 15th PND [TP5-15] continuously and were autopsied on day 16th. Control groups (C) received vehicle. In the Cs serum level of estradiol was 20-fold higher (p<0.001) and FSH was 1,7-fold higher (p<0.05) on 6th PND than on 16th PND, while testosterone did not change. After TP blood level of testosterone increased 2200-fold on 6th PND (p<0.05), and 8-fold on 16th PND. In turn, continuous TP administrations resulted on 16th PND in the increase in testosterone serum level by 2000-times of C without influence on FSH. While the treatment from birth either during initial 5 days or continuously until 15th day decreased testicular weight (p<0.001), tubule length (p<0.05) and SC number (p<0.001), the treatment initiated on 5th PND had no effects. TP reduced serum estradiol level on 6th PND by 13-fold (p<0.01), but doubled it on 16th PND. CONCLUSION Neonatal rats secrete estradiol and FSH in the amounts greatly extending those presented during further development. Testosterone inhibits testicular growth and SC number acting during first 5 neonatal days by decreasing FSH secretion, but is not effective during further development. Direct inhibitory influence of testosterone or trough its increased aromatisation to estradiol beyond neonatal period may be responsible for sustained inhibition of testes growth and SC number during infancy.

Relationship between sexual function, body mass index and levels of sex steroid hormones in young men

INTRODUCTION In older men, sexual disorders may be the result of a decrease in testosterone and an increase in sex hormone binding globulin (SHBG) serum levels. Although obesity may enhance the decline of testosterone, it is also the cause of metabolic disorders, which are additional risk factors of erectile dysfunction. The purpose of this study was to investigate whether elevated body weight is associated with decreased serum testosterone concentrations and reduced sexual function in young men. MATERIAL AND METHODS Data on general health, medication, depressive symptomatology and sexual life was obtained from 136 men aged 20-49 years. Blood levels of LH, total testosterone (TT), dehydroepiandrosterone sulfate (DHEA-S), oestradiol, SHBG, total cholesterol, LDL- and HDL-cholesterol, and triglycerides were determined. Body mass index (BMI), waist to hip ratio (WHR) and free testosterone index (FTI) were calculated. RESULTS A significantly reduced occurrence of sexual fantasies, morning erections and erectile function scores was observed in the oldest group compared to the youngest men with normal BMI, although orgasmic function was unchanged. A significant decrease in TT serum levels was observed in obese 30-year-olds compared to men with normal BMI, while in obese 40-year-olds decreased LH and SHBG levels were also found. No differences in the levels of lipids and sexual achievements were found among men with different BMI. However, erectile function and morning erections significantly negatively correlated with age, BMI and WHR, and positively with FTI, but not with other studied hormones and lipids. CONCLUSIONS In young men, obesity can lead to a deterioration of erectile function as a result of lower testosterone levels as the only reason.