Active immunization of prepubertal bulls against testosterone: Seminal and testicular characteristics after puberty

Twenty-four Holstein bull calves were immunized at 1.0 month of age against either testosterone-17-hemisuccinate-human serum albumin (treated bulls) or against human serum albumin alone (control bulls). Booster injections were given monthly through five months of age. Bulls were reimmunized at six months of age with testosterone-17-hemisuccinate-equine serum albumin (treated bulls) or equine serum albumin alone (control bulls). At 12 months of age, eight treated and eight control bulls were electroejaculated twice daily for two days and then castrated. The remaining four bulls in each group were electroejaculated and castrated at 18 months of age. Active immunization against testosterone significantly elevated the binding of (3)H-testosterone in plasma within four weeks. Body weights of bulls were not affected by treatment. Concentrations of luteinizing hormone (LH) and follicle stimulating hormone (FSH) in plasma were generally not altered by treatment. At castration at 12 months of age, testosterone-immunized bulls tended to have greater (P < 0.15) parenchymal weights and had 30% greater (P < 0.07) daily sperm production (DSP) rates than control bulls; seminal characteristics (motility and intact acrosomes) were not affected. At 18 months of age, testosterone-immunized bulls had 21% greater (P < 0.07) parenchymal weights and 35% greater (P < 0.04) DSP rates than control bulls; again, seminal characteristics were not affected. It appears that prepubertal active immunization against testosterone is a potential means of increasing testicular size and sperm production rates in postpubertal bulls.     

Effect of hypoxia by intermittent altitude exposure on semen characteristics and testicular morphology of male rhesus monkeys

Semen characteristics and testicular morphology of rhesus monkeys were studied on exposure to a simulated high altitude of 4411 m for 21 days. There was a partially reversible decrease in the semen volume, sperm count and sperm motility, as well as an elevation of pH and fructose concentration. These changes were associated with degeneration of the germinal epithelium and spermatogenic arrest at the end of third week of exposure which had not recovered even 3 weeks after the exposure.     

Effects of gold on testicular steroidogenic and gametogenic functions in immature male albino rats

The present study was undertaken to evaluate the effects of gold chloride, a metallic earth salt, on steroidogenic and gametogenic functions of testis in immature rats. Immature rats of Wistar strain, were injected (s.c.) with gold chloride at the dose of 0.3 mg and 0.5 mg/kg body weight/day for 26 days. All the treated animals along with the vehicle-treated controls were sacrificed 24 hours after last injections. Testicular steroidogenic activity was evaluated by measuring the activities of two steroidogenic key enzymes, Delta5-3beta-hydroxysteroid dehydrogenase (Delta5-3beta-HSD) and 17-beta hydroxysteroid dehydrogenase (17-beta HSD). Gametogenic capacity was determined by counting the number of germ cells at stage VII of seminiferous cycle. Plasma levels of testosterone (T) was measured by radioimmunoassay (RIA). Administration of gold chloride at a dose of 0.3 mg/ kg body weight for 26 days led to insignificant changes of testicular Delta5-3beta-HSD,17beta-HSD activities and gametogenesis along with plasma T. In contrast 0.5 mg gold chloride treatment for 26 days caused a significant increase in plasma T (p < 0.001) along with stimulation of testicular Delta5-3beta-HSD activity (p < 0.001) and 17beta-HSD activity (p < 0.001). Gametogenic activity exhibited a significant increase in the number of step 7 spermatids (7Sd) (p < 0.001) at stage VII of seminiferous cycle when compared to control. The results of our experiment suggest that gold chloride treatment might be associated with significant stimulatory effects on testicular activities. Furthermore, since hormonal changes, altered steroidogenic enzymes and gametogenic activities were evident to a specific dose of gold chloride treatment, our data may have some clinical implication on the stimulation of fertility.     

Protective effect of exogenous melatonin on testicular histopathology and histomorphometry of adult rats with domperidone-induced hyperprolactinemia

Hyperprolactinemia is a pathological condition resulting from increased prolactin that directly affects reproduction, as this condition inhibits the release of LH, FSH and gonadal steroidogenesis, bringing several negative clinical associations in reproduction. In contrast, melatonin (MEL) plays an important role in the regulation of steroidogenesis and modulates damages to the process of spermatogenesis. The objective was to analyze the protective effects of exogenous melatonin on the testis of hyperprolactinemic adult rats. Forty-eight male rats were used, divided into two treatment periods: 30 and 60 days, each treatment was subdivided into three groups: Control, Hyper (hyperprolactinemia), and Hyper+MEL (hyperprolactinemia and melatonin). Treatment with melatonin was 200 μg/100 g, subcutaneously. Induction of hyperprolactinemia was obtained with a dose of 4 mg/kg of domperidone, subcutaneously. The results of the histopathology demonstrated that the animals in the Hyper group presented degeneration of germ cells when compared to the control. In addition, the degenerations were presented in smaller quantities in the Hyper+MEL, in both treatment periods, evidencing the benefits of the melatonin in gonadal regeneration. The Hyper group of both treatment periods showed a decrease in tubular diameter, epithelium height, and tubular area, in addition to a decrease in Sertoli cells, when compared to the control and the Hyper+MEL group. In conclusion, the hyperprolactinemia can affect the germinal epithelium and testicular microstructure; the exogenous melatonin has a protective effect against hyperprolactinemia, reducing testicular damage.     

Ellagic acid improved diabetes mellitus-induced testicular damage and sperm abnormalities by activation of Nrf2

Diabetes mellitus induces testicular damage, increases sperm abnormalities, and impairs reproductive dysfunction due to induction of endocrine disturbance and testicular oxidative stress. This study evaluated the reproductive protective effect of ellagic acid (EA) against testicular damage and abnormalities in sperm parameters in Streptozotocin (STZ)-induced diabetic rats (T1DM) and examined some possible mechanisms of protection. Adult male rats were segregated into 5 groups (n = 12 rat/each) as control, control + EA (50 mg/kg/day), T1DM, T1DM + EA, and T1DM + EA + brusatol (an Nrf-2 inhibitor) (2 mg/twice/week). All treatments were conducted for 12 weeks, daily. EA preserved the structure of the seminiferous tubules, prevented the reduction in sperm count, motility, and viability, reduced sperm abnormalities, and downregulated testicular levels of cleaved caspase-3 and Bax in diabetic rats. In the control and diabetic rats, EA significantly increased the circulatory levels of testosterone, reduced serum levels of FSH and LH, and upregulated Bcl-2 and all steroidogenic genes (StAr, 3β-HSD1, and 11β-HSD1). Besides, it reduced levels of ROS and MDA but increased levels of GSH and MnSOD and the transactivation of Nrf2. All these biochemical alterations induced by EA were associated with increased activity and nuclear accumulation of Nrf2. However, all these effects afforded by EA were weakened in the presence of brusatol. In conclusion, EA could be an effective therapy to alleviated DM-induced reproductive toxicity and dysfunction in rats by a potent antioxidant potential mediated by the upregulation of Nrf2.     

Effect of short- and medium-term toxicity of doxorubicin on spermatogenesis in adult Wistar rats

Doxorubicin (DXR) is a widely used chemotherapeutic anticancer agent that has potent activity against several solid and non-solid human malignant tumors, including childhood malignancies. However, DXR has serious toxic effects on tissues with rapid cell cycles, such as myeloid and lymphatic tissues, intestinal mucosa, testes and ovaries. In the present study, the short- and medium-term toxic effects of DXR on the reproductive system of male Wistar rats were evaluated using morphometric and stereological tools to quantify damage to the seminiferous epithelium. Adult male Wistar rats were treated with dose of 7.5?mg/kg of DXR and were sacrificed at seven, 14, 21 and 28?days after treatment. The testes were fixed in glutaraldehyde solution, routinely processed and embedded in plastic for evaluation under a light microscope. A significant reduction in testis weight was found as a result of massive germ cell apoptosis. Differences in comparison to the control group were found in the relative frequency of all stages of the seminiferous epithelium cycle, with significant differences for stages VIII–XI. Apoptosis significantly decreased the number of pachytene spermatocytes in the stages evaluated (I, II–III and VIII) at seven and 14?days. At 21 and 28?days after treatment, the testes exhibited the massive loss of germ cells that resulted in a missing cell layer. Moreover, reductions in the height of seminiferous tubules, tubular diameter and tubular compartment as well as an increase in the intertubular compartment were found in the period studied.     

不同温湿度组合对甜菜夜蛾生长发育及繁殖力的影响

不同温湿组合对甜菜夜蛾各虫态生长发育和繁殖力有明显的影响,适宜该虫生长发育的温湿度为２６℃与ＲＨ８０％或ＲＨ９４％两个组合．在这种条件下,其卵孵化率、１～５龄幼虫存活率、蛹羽化率、雌虫比率、产卵的雌虫比率和平均产卵量分别为８２．６３％～８３．７０％、８１．９０％～８２．４７％、８８．００％～８８．０３％、９０．４０％～９１．００％、９３．３６％～９４．１７％、９５．９７％～９６．２６％、９２．７７％～９４．１６％、０．４２～０．４３、０．９８和６０５～６０６粒／雌,且明显高于其它温湿组合．在温湿度为３２℃与ＲＨ９４％条件下,该虫的内禀增长能力最大（０．２２５）．     

Regulation of testicular function in the stallion: an intricate network of endocrine, paracrine and autocrine systems

It is well established in many mammalian species, including the horse that normal testicular function is dependent upon a functional hypothalamic-pituitary-testicular (HPT) axis, which involves classic feedback mechanisms. The major HPT hormones involved in the stallion are gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone (T), estrogens (Es) and inhibin (INH). Although prolactin (PRL) fluctuates with season in the stallion and both PRL and thyroid hormone (TH) affect reproduction in other male species, their effects on stallion reproduction have not been elucidated. Growth hormone (GH) in the stallion may be involved in sperm motility, production and secretion of insulin-like growth factor-1 (IGF-1) and LH-induced testosterone release. The action of these hormones and the products involved for normal spermatogenesis require cell to cell communication within the testis. The somatic cell types, Leydig, Sertoli and peritubular myoid cells, all support germ cell development, maturation and release into the seminiferous tubule lumen. The cell to cell crosstalk involves an intricate network of paracrine-autocrine systems that support the endocrine input to modulate cell function. In other male species, researchers have demonstrated the reproductive effects of such paracrine-autocrine factors as IGF-1, transferrin, androgens, estrogens, inhibin, insulin like peptide 3 (INSL3), beta-endorphin and oxytocin. The specific nature and relative contribution of these various factors on testicular function in fertile and subfertile stallions are under investigation. This review summarizes current information regarding the nature of the multiple endocrine-paracrine-autocrine systems that may be necessary for normal testicular function in the stallion.     

Effect of anti-estrogen and anti-progesterone on spermatogenesis,testosterone production and expression of steroidogenic enzyme genes in adult male rats

The present study was planned to investigate the anti-spermatogenic and anti-steroidogenic effects of Clomiphene Citrate (CC) an anti-estrogen and Mifepristone (MT) an anti-progesterone in the testis of male rats. Following the oral administration of 1.0 mg and 5.0 mg/kg b.w/day of each for the duration of 30 and 60 days, quantitation of spermatogenesis, RIA for serum and intra-testicular testosterone levels, western blotting and RT-PCR for expression of StAR, 3β-HSD and P450arom enzymes in the testis was done. Clomiphene Citrate at 5.0 mg/kg b.w/day for 60 days significantly reduced testosterone (T) levels however the effect was not significant with the lower doses. Reproductive parameters in animals treated by Mifepristone remained mostly unaffected, however, a significant decline in testosterone levels and altered expression of selected genes was observed in 5.0 mg for the 30d treatment group. Clomiphene Citrate at higher doses affected the weights of the testis and secondary sex organs. Seminiferous tubules revealed hypo-spermatogenesis with a significant decrease in the number of maturing germ cells and a reduction in tubular diameter. Attenuation in serum testosterone was associated with the downregulation of expression in StAR, 3β-HSD, and P450arom mRNA and protein levels in the testis even after 30 d of CC administration. The results indicate that the anti-estrogen (Clomiphene Citrate) but not anti-progesterone (Mifepristone) induces hypo-spermatogenesis in rats which are associated with a downregulation of expression of two of the steroidogenic enzymes, 3β-HSD and P450arom mRNA and StAR protein.     

Experimental mild increase in testicular temperature has drastic,but reversible,effect on sperm aneuploidy in men: A pilot study

In mammals testicular and epididymal temperature increase impairs spermatogenesis. This experimental study investigates the effects of a mild testis temperature increase (i.e. testis temperature remains below core body temperature) on sperm aneuploidy in men. In 5 fertile volunteers a testicular temperature increase was induced by maintaining the testes at suprascrotal position using specially designed underwear for 15 ± 1 h daily for 120 consecutive days. After heating men were followed for next 180 days. A control group (27 men) was recruited. Semen samples were collected before, during and after heating period and analyzed for chromosomes X, Y and 18 for aneuploidy using FISH. A total of 234,038 spermatozoa were studied by FISH. At day 34 of heating, mean sperm aneuploidy values were not modified. From day 34 of heating until day 45 post heating, FISH evaluation was not possible due to the drastic fall of sperm count. At day 45 post-heating total sperm aneuploidy percentage was twice higher than before heating whereas. Sex disomy (sperm XY18), sex chromosome nullisomy (sperm 18) were significantly higher than controls. These effects were completely reversed at 180 days post heat exposure. Conclusion: A mild rise in testicular temperature significantly increases sperm aneuploidies, reflecting an effect on the meiosis stage of spermatogenesis. The effect of heating was reversible and suggests that recovery of aneuploidy to normal values requires at least two cycles of spermatogenesis. Nonetheless, the low number of volunteers was a limitation of this pilot study and warrants further research on larger population.     

外来入侵害虫棉花粉蚧雄虫生殖能力研究

采用单头雄虫与不同数量雌虫配比的方法研究了棉花粉蚧雄虫的生殖能力。结果表明,与1～7头雌虫配比,雄虫的交配成功率分别为94.4%、91.2%、85.4%、80.7%、77.7%、69.5%、66.2%;产仔雌虫数量与雌雄性比关系符合逻辑斯蒂曲线方程Ff=5.2159EXP(-2.5304EXP (-0.421739N)),1头雄虫平均可以满足4～5 头雌虫生殖需要,最多为5.22头;与单头雄虫交配后雌虫总产仔量由358.8头增大至1274.2头,其数量与雌雄性比关系符合S型增长曲线F?t=1524.589e-1.3922/N,总产仔量最大可达1525头;单雌产仔量先由358.8头上升至427.6头,其后逐渐下降至266.5头;子代性比(♀:♂)变化无规律,为1.13～1.86;子代中雌虫数量由206.1头增大到727.4头,其数量与雌雄性比关系可由F?of=840.1124e-1.2599/N描述,最大值是840头。     

Impact of mild temperature hardening on thermotolerance, fecundity, and Hsp gene expression in Liriomyza huidobrensis

The pea leafminer, Liriomyza huidobrensis, is one of the most important economic insect pests around the world. Its population fluctuates greatly with seasonal change in China, and temperature was thought to be one of the important reasons. In attempt to further explore the impact of disadvantageous temperature on L. huidobrensis, 1-day-old adults were shocked at various temperatures (10, 25, 32, and 35 degrees C, respectively) for 4h, and the effects on thermotolerance, feeding, and fecundity were studied. Meanwhile the expression of five heat shock genes (hsp90, 70, 60, 40, and 20) was examined by real-time quantitative PCR. Our results showed that both 32 and 35 degrees C hardenings remarkably increased adult heat resistance, whereas cold tolerance was not improved accordingly. No cross resistance in response to cold and heat stresses was observed. Both adult feeding and fecundity were dramatically reduced, but no effect was observed on egg hatching, larval survival, pupal eclosion, or sex ratio. The results indicate that the deleterious effect on fecundity is the result of direct cessation of oviposition during the period of stress. Simultaneously, the mRNA levels of hsp70 and hsp20 significantly increased upon thermal hardening. Taken together, our results suggest that mild heat hardening improves thermotolerance of L. huidobrensis at the cost of impairment on fecundity, and the induced expression of hsp70 and hsp20 may play an important role in balancing the functional tradeoff.     

Breaking the temperature-size rule: Thermal effects on growth,development and fecundity of a crustacean from temporary waters

The temperature-size rule (TSR) is a well-established phenomenon to describe the growth response of ectotherms to temperature by which individuals maintained at low temperatures grow more slowly, but attain a larger size upon maturity. Although there are adaptive and non-adaptive theories about the plasticity of body size in response to temperature, these cannot be applied to all ectotherms, and little is known about the changes in growth and development rates through ontogeny. The ostracod species Heterocypris bosniaca, an inhabitant of freshwater temporary ponds, was used to examine the growth and development rates of its nine growth stages and female fecundity at four different temperatures (15 °C, 20 °C, 25 °C and 30 °C). The development rate of this species accelerates with increasing temperature, reaching a maximum value at 25 °C. The growth factor has a reverse-TSR in younger instars, and the typical TSR is followed only in the last two moults, resulting in non-monotonic response of adult size to temperature. Fecundity (total offspring per female) was not directly related to adult size and was generally higher at lower temperatures. Our results agree with recent research showing that the TSR may vary during ontogeny, and may not be a general trend in ostracod species from temporary waters. Indeed, adult carapace size seems to follow the pattern of a thermal reaction norm, probably influenced by the reduction of oxygen bioavailability at low temperature and the drastic increase in metabolic demand at the upper extreme of the thermal gradient.     

Return of testicular function after vaccination of boars against GnRH: consequences on testes histology

Traditionally, male pigs are surgically castrated without anaesthesia to avoid later occurrence of the sex odour of androstenone in the carcass. Active immunization against gonadotropin-releasing hormone (GnRH) is a painless alternative which inhibits LH and thus steroidogenesis in the Leydig cells. In a preceding study we clarified the return of Leydig cell function after the last dose of antigen by measuring hormones, and found a considerable variation (10 to 24 weeks) till return of their function (testosterone 0.5 ng/ml blood plasma). The present paper analyses histological data on testes characteristics of the same six boars at an age of 52 weeks (26 weeks after last immunization). Data were compared to another four boars which were not immunized but slaughtered at the same age. Testis weight was related to the concentration of testosterone in blood. In boars, that first returned to testicular function, testis weight even exceeded those in controls probably due to rebound phenomena. Differences in testis weight were mainly due to differences of Leydig cell content of cytoplasm, and less to the size of nuclei. Additionally, the height of seminiferous epithelium was slightly dependent on testosterone concentrations and contributed moderately to differences in testis weight. Altogether, normalization of testicular function, even after return to steroidogenesis, requires another 13 weeks.     

The effects of density,rainfall and environmental temperature on body condition and fecundity in the common toad,Bufo bufo

The body length and body weight of all adult common toads (Bufo bufo) breeding at a pond in south Dorset were measured between 1983 and 1993. Each toad was placed into one of four categories depending on its sex and whether it was either a first time breeder or an animal that had previously bred. The body condition of each male and female toad for each year was compared with the average body condition of all the male and female toads captured over the 11 years of the study so that between-year differences in condition could be detected. Changes in body condition were compared with changes in body condition were compared with changes in toad density, rainfall and climatic temperature during the previous summer (March–September), during hibernation (October–February) and during the month preceding the start of spawning. During the study there was a decline in the body condition of all toad categories and these changes were significantly correlated with changes in toad density and climatic temperature. Toads were also more likely to enter hibernation in poor condition following a hot dry summer than after either cool wet or hot wet summers. Body condition explained 41% of the size-specific variation in fecundity.     

Developmental appearance of the Ca2+-binding proteins parvalbumin,calbindin D-28K,S-100 proteins and calmodulin during testicular development in the rat

Summary Calcium and intracellular Ca²⁺-binding proteins are possibly involved in hormone production and spermatogenesis in rat testis. Parvalbumin, calbindin D-28K, S-100 proteins and calmodulin were localized in the Leydig cells, which are sites of testosterone synthesis. Only the appearance of parvalbumin-immunoreactivity is closely correlated to testosterone production during development of the testes. Calbindin D-28K-immunoreactivity persisted in foetal-type Leydig cells and in adult-type Leydig cells at all stages of development. S-100-immunoreactivity was low during all foetal stages, absent between birth and puberty, and increased thereafter. Calmodulin staining is most prominent in the cytoplasm of developing spermatocytes and of maturing spermatids. All four proteins co-exist in the seminiferous tubules. The distinct localization and developmental appearance of these proteins suggests different regulatory roles in Leydig cell function and spermatogenesis.     

Effect of different cryoprotectant agents on spermatogenesis efficiency in cryopreserved and grafted neonatal mouse testicular tissue

Restoration of male fertility associated with use of the cryopreserved testicular tissue would be a significant advance in human and animal assisted reproductive technology. The purpose of this study was to test the effects of four different cryoprotectant agents (CPA) on spermatogenesis and steroidogenesis in cryopreserved and allotransplanted neonatal mouse testicular tissue. Hank’s balanced salt solution (HBSS) with 5% fetal bovine serum including either 0.7 M dimethyl sulfoxide (DMSO), 0.7 M propylene glycol (PrOH), 0.7 M ethylene glycol (EG), or glycerol was used as the cryoprotectant solution. Donor testes were collected and dissected from neonatal pups of CD-1 mice (one day old). Freezing and seeding of the testicular whole tissues was performed using an automated controlled-rate freezer. Four fresh (non-frozen) or frozen–thawed pieces of testes were subcutaneously grafted onto the hind flank of each castrated male NCr nude recipient mouse and harvested after 3 months. Fresh neonatal testes grafts recovered from transplant sites had the most advanced rate of spermatogenesis with elongated spermatid and spermatozoa in 46.6% of seminiferous tubules and had higher levels of serum testosterone compared to all other frozen–thawed-graft groups (p < 0.05). Fresh grafts and frozen–thawed grafts in the DMSO group had the highest rate of tissue survival compared to PrOH, EG, and glycerol after harvesting (p > 0.05). The most effective CPA for the freezing and thawing of neonatal mouse testes was DMSO in comparison with EG (p < 0.05) in both pre-grafted and post-grafted tissues based on histopathological evaluation. Likewise, the highest level of serum testosterone was obtained from the DMSO CPA group compared to all other cryoprotectants evaluated (p < 0.05). The typical damage observed in the frozen–thawed grafts included disruption of the interstitial stroma, intercellular connection ruptures, and detachment of spermatogonia from the basement membrane. These findings indicate that neonatal mouse testes were most effectively preserved when frozen with HBSS medium with DMSO and that the type of CPA is a significant factor to obtain the most advanced stages of spermatogenesis and steroidogenesis after cryopreservation, thawing, and transplantation of neonatal mouse testes.     

The influence of temperature and resource level on the fecundity of a predatory planktonic mite,Piona exigua Viets

Summary Piona exigua Viets is a predaceous freshwater mite that can potentially affect the population densities of its cladoceran prey. As part of a study of the effect of Piona exigua on its prey populations we measured the effects of water temperature and prey density on the lifespan, age at first reproduction and per capita egg production of adult female mites. Mites were raised in the laboratory at five prey (Ceriodaphnia, Daphnia) densities (5, 15, 30, 60, 120/l) at 15° C and at four temperatures (10, 15, 18, 22° C) at c. 60 prey/l. In response to increased food level, mites increased the number of eggs laid to reach a maximum at 60 prey/l, the rate at which they were laid increased and the pre-reproductive period was shorter. Low temperatures prolonged the pre-reproductive period. At temperatures above 10° C, food level and temperature had more influence on the timing of reproductive events (growth rate, oviposition rate, age at first reproduction) than on the size of females at first reproduction. When temperatures exceed 10° C and food levels exceed 5 prey/l the major scope for reproductive plasticity in Piona lies in the timing and duration of egg production.