Study on Testicular Toxicity of 2-Bromopropane, an Environmental Endocrine Disrupter

2-Bromopropane (2-BP) is considered as a kind of environmental endocrine disrupters (EDs). Its reproductive and hematopoietic toxicity has aroused the attention of international toxicologists during the past five years.In the present study, we aimed to determine experimentally the testicular toxicity of 2-BP in male rats. Materials & Methods Forty SD male rats were divided into four groups of 10 rats each. The rats were intra-abdominally administered 2-BP once per day for 5 days continuously at the doses of 1800 mg/kg, 600 mg/kg, 200 mg/kg and normal saline, respectively. The rats were dissected one week after the first administration. Results The body weight, absolute testes weight and relative testes weight of the rats in 1 800 mg/kg dose group decreased significantly with comparison to those of the con- trol group,while the weight of accessory gonads showed no significant change. With the increase of dosage, the seminiferous tubules damage rate aggravated while the ratio of spermatogonia in total germ cells fell with P<0. 05. The seminiferous tubule area of rats in 1800 mg/kg group also reduced significantly. Under light microscopic examination, the spermatogonia of administered rats showed degeneration and chro- matin condensation. The nucleus of spermatocytes appeared hyperchromatic and py- knotic.Obvious testicular damage could be found in rats of high dose group, including large amount of spermatogonia necrosis or loss and reduced spermatocyte number. The electron microscopic findings were similar to those of the light microscopy, except that typical morphological change was found in the middle dose group: the structure of spermatogonia was destroyed, mitochondrion and endoplasmic reticulum scattered outside, nucleus disintegrated; some of the spermatocytes' membrane became nuclear, chromatin condensed and cogulation necrosis appeared; the nuclear membrane of round spermatids also showed slight damage. Conclusion The results indicated that testis was the target organ of 2-BP's reproduc- tive toxicity. The testicular toxicity of 2-BP started from damaging spermatogonia and its damage on spermatogonia was most obvious among all germ cells.

Phthalate Exposure and Human Semen Quality in Shanghai:A Cross-sectional Study

Objective To monitor the level of phthalates in human semen samples and to analyze the relationship between phthalate levels and semen parameters. Methods Concentrations of three kinds of commonly used phthalates （di-ethyl phthalate, DEP; di-n-butyl phthalate, DBP; di-2-ethylhexyl phthalate, DEHP） were measured using reversed-phase HPLC. Semen parameters were measured by computer aided sperm analysis （CASA）. Results The three phthalates were detected in most of the biological samples, with median levels of 0.30 mg/L （0.08-1.32 mg/L） in semen specimens. There was a significant positive association between liquefied time of semen and phthalate concentrations of semen. The correlation coefficient was 0.456 for DEP, 0.475 for DBP, and 0.457 for DEHP, respectively. There was no significant difference between phthalate concentrations of semen and sperm density or livability, though the correlation coefficients were negative. Conclusion These results suggest that people who reside in Shanghai are exposed to phthalates, especially to DBP and DEHP. Although the level of phthalates is relatively mild, an association of phthalate levels and reduced quality of human semen has been shown in the present study.

Nitrogen-doped titanium dioxide/schwertmannite nanocomposites as heterogeneous photo-Fenton catalysts with enhanced efficiency for the degradation of bisphenol A

Potential health risks related to environmental endocrine disruptors(EEDs)have aroused research hotspots at the forefront of water treatment technologies.Herein,nitrogen-doped titanium dioxide/schwertmannite nanocomposites(N-TiO_(2)/SCH)have been successfully developed as heterogeneous catalysts for the degradation of typical EEDs via photo-Fenton processes.Due to the sustainable Fe(Ⅲ)/Fe(Ⅱ)conversion induced by photoelectrons,as-prepared N-TiO_(2)/SCH nanocomposites exhibit much enhanced efficiency for the degradation of bisphenol A(BPA;ca.100% within 60 min under visible irradiation)in a wide pH range of 3.0-7.8,which is significantly higher than that of the pristine schwertmannite(ca.74.5%)or N-TiO_(2)(ca.10.8%).In this photo-Fenton system,the efficient degradation of BPA is mainly attributed to the oxidation by hydroxyl radical(·OH)and singlet oxygen(^(1)O_(2)).Moreover,the possible catalytic mechanisms and reaction pathway of BPA degradation are systematically investigated based on analytical and photoelectrochemical analyses.This work not only provides a feasible means for the development of novel heterogeneous photo-Fenton catalysts,but also lays a theoretical foundation for the potential application of mineral-based materials in wastewater treatment.