[Increase of apoptosis and decrease of sperm motility induced by oxidative stress after exposed to butyl p-hydroxybenzoate].

OBJECTIVE: To explore the effect and mechanism of butyl phydroxybenzoate( BP) on sperm motility, oxidative stress and apoptosis. METHODS: Semen samples from 20 healthy sperm donors were randomly divided into four groups:group control, BP 200 µmol/L, BP 400 µmol/L and BP 800 µmol/L, each group had five parallel samples. The spermatozoa were cultured with BP for 4 h in vitro, with the exposed concentration of BP at 0, 200, 400 and 800 µmol/L, respectively. The influence of BP on spermatozoa were analyzed by sperm activity, cytotoxicity, the rate of reactive oxygen species( ROS) positive cell and apoptosis. RESULTS: The total sperm activity in group BP200 µmol/L, BP 400 µmol/L and BP 800 µmol/L were( 47. 67 ± 3. 93) %, ( 32. 79 ±2. 90) %, ( 10. 51 ± 5. 88) % respectively, which were significantly lower than control( 26. 44 ± 7. 83) %. Compared with the control group, the survival rate of sperm in the three experiment groups were( 63. 36 ± 9. 08) %, ( 49. 72 ± 7. 15) %, ( 29. 91 ±5. 93) % respectively. Rate of ROS positive cells in the three experiment groups were( 24. 67 ± 0. 50) %, ( 54. 50 ± 3. 40) %, ( 59. 93 ± 3. 47) % respectively, which were significantly higher than control( 8. 63 ± 0. 57) %. The rate of late stage apoptosis were( 11. 8 ± 1. 74) %, ( 12. 87 ± 0. 25) %, ( 14. 60 ± 0. 87) % respectively, which were significantly higher than control( 9. 63 ± 1. 00) %. The level of sperm ROS and the late stage apoptosis rate were negatively correlated with the total sperm motility, correlation coefficient were- 0. 727 and- 0. 688 respectively( P < 0. 05). CONCLUSION: BP has cytotoxicity and can reduce sperm motility and promote the production of sperm ROS.

n-butylparaben induces male reproductive disorders via regulation of estradiol and estrogen receptors.

It is well known that inappropriate exposure to exogenous hormones during fetal or neonatal life, such as testosterone (T) and estradiol (E2 ), leads to adverse reproductive outcomes. In our previous study, the reproductive dysfunction of male rats was characterized by an E2 increase and T decrease after in utero and lactation exposures to n-butylparaben (n-BP). In this study, we investigated the synthesis and metabolism pathways of steroid hormones, hormone receptors and the epigenetic modification of male offspring on postnatal day (PND) 21 and PND90 to explore the possible mechanisms of endocrine and reproductive disorders. The expression of steroidogenic acute regulatory protein (StAR), cytochrome cholesterol side-chain cleavage enzyme (P450scc), estrogen sulfotransferase (SULT1E1) and androgen receptor (AR) in the testes was significantly decreased at the transcript and protein levels; in addition, aromatase (CYP19) and estrogen receptor α (ERα) expression was significantly increased and the methylation rate of the ERα promoter was significantly decreased. These results suggest that increased CYP19 expression and decreased SULT1E1 expression are responsible for the E2 increase. This effect promotes the expression of ERα, which plays a pivotal role in regulating reproductive and endocrine disorders of male rats exposed to n-BP. Furthermore, the epigenetic hypomethylation of ERα is involved in this regulation processes. Our study is the first to report on the possible mechanism of male rat reproductive disorders induced by the xenoestrogenic chemical n-BP. Copyright © 2016 John Wiley & Sons, Ltd.

[Testicular oxidative stress and downregulation of CYP17a1 indused by di (n-butyl) phthalate inhibit synthesis of testosterone].

OBJECTIVE: To explore the relationship and possible mechanisms between testicular oxidative injury caused by DBP and the testosterone synthesis pathway. METHODS: Twenty-four male Wistar male rats (4-wk-old) were randomly divided into 4 groups, three doses of DBP (80, 200 and 500 mg/kg) groups and a vehicle (corn oil) control group, 6 animals each. The rats were respectively administered by gavage once a day for four weeks. They were sacrificed after 4 weeks treatment and the body weights, testis, epididymis were weighed, respectively. The oxidation of MDA and ROS, the activity changes of antioxidases SOD, CAT and GPx-1, as well as the activities of steroid synthetases 3ß-HSD1, 17ß-HSD3 in the testis homogenate were measured by biochemical methods. The levels of testosterone, LH, FSH in peripheral blood and testosterone, ASD in testis were measured by radioimmunoassay. The intensities of expresses of StAR, P450scc, 3ß-HSD1, 17ß-HSD3 and CYP17a1 mRNA were detected by real-time qPCR. RESULTS: In 500 mg/kg dose group, the body weights and weigths of testis were decreased obviously (P < 0.05). The concentration of serum LH and FSH was increased, the consentration of serum T, testicular T and testicular ASD was decreased (P < 0.05). The oxidation of MDA and ROS was increased distinctly and the activities of SOD, CAT, GPx-1 and 3ß-HSD1 were reduced (P < 0.05). StAR, P450scc, 3ß-HSD1 and CYP17a1 mRNA were decreased, 17ß-HSD3 mRNA was increased (P < 0.05). In 200 mg/kg dose groups, LH, FSH level in peripheral blood were increased and ASD level in testis was decreased (P < 0.05). The oxidation of ROS was increased and activity of GPx-1 and 3ß- HSD1 were decreased (P < 0.05). StAR, P450scc and CYP17a1 mRNA were decreased (P < 0.05). There were no changes in 80 mg/kg group. CONCLUSION: DBP exposure disturbed the balances of oxidation/antioxidation, then result in the decline of GPx-1 activity, CYP17a1 mRNA and ASD level which caused the decrease of testosterone synthesis in leydig cell. It is speculated that the decrease of CYP17a1 may be one of the mechanisms of toxic effects of DBP.

[Interference of testosterone synthesis through HPGA and ERalpha pathway after 17beta-estradiol exposure to regulate spermatogenesis].

OBJECTIVE: To evaluate the effects of 17beta-estradiol (E2) exposure on male reproductive endocrine system, and study the potential mechanism. METHODS: Male Wistar rats were gavaged with E2 (1.00, 0.50, 0.10, 0.01 mg.kg(-1).d(-1)) for 8 weeks, with corn oil as control. The testes weight and testicular organ coefficient and sperm parameter were examined. Serum levels of zinc and calcium were measured by atomic absorption spectrophotometry. Serum hormone concentrations were determined by RIA. The expression of testosterone synthetase mRNA were assessed by RT-PCR. The expression of estrogen and androgen receptor protein were detected by Western blot. RESULTS: Testis weight and testicular coefficient were significantly declined. Serum testosterone levels were significantly decreased. Serum estradiol levels showed a significant increase in a dose-related manner (P<0.01). Blood zinc had a significant decrease at 0.50 and 1.00 mg.kg(-1) d(-1) (P<0.01). Epididymal cauda sperm counts declined at 0.50 and 1.00 mg/kg (P<0.01). The expression of steroidogenic acute regulatory protein (StAR) and cytochrome cholesterol side-chain cleavage enzyme (P450scc) mRNA were decreased. The expression of ERa protein was increased, and AR protein was decreased. CONCLUSION: Exposure to E2 in puberty could interfere with the development of testis, The potential including testosterone biosynthesis and spermatogensis in adulthood. mechanism may be indirectly through disturbing the balance of HPGA, and directly through up-regulating the level of ERa protein consequently inhibiting testosterone synthetase. Blood zinc was involved in mediating spermatogensis by E2 exposure.

Polyacrylate/nanosilica causes pleural and pericardial effusion, and pulmonary fibrosis and granuloma in rats similar to those observed in exposed workers.

Nanomaterials offer great benefit as well as potential damage to humans. Workers exposed to polyacrylate coatings have pleural effusion, pericardial effusion, and pulmonary fibrosis and granuloma, which are thought to be related to the high exposure to nanomaterials in the coatings. The study aimed to determine whether polyacrylate/silica nanoparticles cause similar toxicity in rats, as observed in exposed workers. Ninety male Wistar rats were randomly divided into five groups with 18 rats in each group. The groups included the saline control group, another control group of polyacrylate only, and low-, intermediate-, and high-dose groups of polyacrylate/nanosilica with concentrations of 3.125, 6.25, and 12.5 mg/kg. Seventy-five rats for the 1-week study were terminated for scheduled necropsy at 24 hours, 3 days, and 7 days postintratracheal instillation. The remaining 15 rats (three males/group) had repeated ultrasound and chest computed tomography examinations in a 2-week study to observe the pleural and pericardial effusion and pulmonary toxicity. We found that polyacrylate/nanosilica resulted in pleural and pericardial effusions, where nanosilica was isolated and detected. Effusion occurred on day 3 and day 5 post-administration of nanocomposites in the 6.25 and 12.5 mg/kg groups, it gradually rose to a maximum on days 7-10 and then slowly decreased and disappeared on day 14. With an increase in polyacrylate/nanosilica concentrations, pleural effusion increased, as shown by ultrasonographic qualitative observations. Pulmonary fibrosis and granuloma were also observed in the high-dose polyacrylate/nanosilica group. Our study shows that polyacrylate/nanosilica results in specific toxicity presenting as pleural and pericardial effusion, as well as pulmonary fibrosis and granuloma, which are almost identical to results in reported patients. These results indicate the urgent need and importance of nanosafety and awareness of toxicity of polyacrylate/nanosilica.

Nanosilica and Polyacrylate/Nanosilica: A Comparative Study of Acute Toxicity.

We compared the acute toxicity of nanosilica and polyacrylate/nanosilica instillation in Wistar rats (n = 60). Exposure to nanosilica and polyacrylate/nanosilica showed a 30% mortality rate. When compared with saline-treated rats, animals in both exposure groups exhibited a significant reduction of PO2 (P < 0.05) at both 24 and 72 hr. after exposure. Both exposure groups exhibited a significant reduction of neutrophils in arterial blood compared to saline controls (P < 0.05) 24 hr. after exposure. The levels of blood ALT and LDH in exposed groups were found to be significantly increased (P < 0.05) 24 hr. following exposure. The exposed groups exhibited various degrees of pleural effusion and pericardial effusion. Our findings indicated respiratory exposure to polyacrylate/nanosilica and nanosilica is likely to cause multiple organ toxicity.

Effects of n-butylparaben on steroidogenesis and spermatogenesis through changed E2 levels in male rat offspring.

Parabens are widely used as antibacterial agents, which are concerned recently in the relationship between the use of parabens and reproductive toxicity. So that reassessment of the risk of parabens is needed. In this study, one of parabens, n-butylparaben (n-BP) was orally administered to pregnant Wistar rats (0, 64, 160, 400 and 1000 mg/kg/day) from gestation day (GD) 7 through postnatal day (PND) 21. Reduced anogenital distance (AGD) and delayed preputial separation (PPS) were observed in the male offspring. The weights of the testes were significantly reduced at PND 21-90. The weights of the epididymides were significantly reduced at all monitoring points, except PND 35. Seminal vesicle weights were significantly reduced on PND 21. Serum testosterone (T) was significantly decreased, especially on PND 49. The levels of 17ß-estradiol (E2) showed an increase at each of the tested points except on PND 180. Serum luteinising hormone (LH) and follicle-stimulating hormone (FSH) levels in the n-BP treated groups were lower on PND 21, 35 and 49 but elevated on PND 90 compared to control levels. n-BP reduced epididymal cauda sperm counts and daily sperm production in a dose-dependent manner; this difference was statistically significant at exposure groups of 400 and 1000 mg/kg/day. The present study strongly suggests that exposure to n-BP in utero and during lactation has adverse effects on the reproductive system in male offspring, with a no observed adverse effect level (NOAEL) of 160 mg/kg/day. To our knowledge, this is the first study that reports increased E2 levels of male rats following n-BP exposure; we suggest that E2 levels may be considered as biomarkers for some endocrine disrupting chemicals (EDCs).