Flow cytometric assessment of ethylene glycol monoethyl ether on spermatogenesis in rats

Testicular effect of a mixture of 2-methoxyethanol and 2-ethoxyethanol in rats

BACKGROUND

2-Methoxyethanol (ME) and 2-ethoxyethanol (EE) represent a large group of chemicals which are used separately or as mixtures. These compounds exert multidirectional toxic effects. The present studies aimed to demonstrate the effects of ME and EE alone and their mixture on the reproductive organs in the rats.

METHODS

Male Wistar rats were treated subcutaneously with ME and EE alone (1.25-5.0mM/kg/day) or with their mixture (1:1) for 4 weeks. After completion of the experiment, the testes, epididymides, and prostate were weighed. In post-mitochondrial supernatant of the testes, the level of total protein, non-protein and protein sulfhydryl groups, malondialdehyde, total antioxidant status, and glutathione peroxidase and glutathione reductase activities were determined.

RESULTS

Exposure to ME alone resulted in a dose-dependent decrease in the organ weights, the total protein, non-protein and protein sulfhydryl groups. EE alone led to less marked alterations. Co-exposure to ME and EE caused alterations similar as in the rats treated with ME alone.

CONCLUSIONS

Marked testicular atrophy, decrease in epididymis and prostate weights are predominant effects of the repeated exposure to relatively low doses of ME and EE. A decrease in the total protein level, and protein sulfhydryl groups may be responsible for testicular atrophy. A significant depletion of non-protein sulfhydryl groups and occasionally elevated glutathione peroxidase activity may indicate that ME and EE resulted in disturbances of pro-oxidant/antioxidant balance. The study suggests that testicular toxicity in male rats co-exposed to ME and EE is mainly caused by the former compound.

A standardized extract of Ginkgo biloba suppresses doxorubicin-induced oxidative stress and p53-mediated mitochondrial apoptosis in rat testes

BACKGROUND AND PURPOSE

Doxorubicin evokes oxidative stress and precipitates cell apoptosis in testicular tissues. The aim of this study was to investigate whether the Ginkgo biloba extract 761 (EGb), a widely used herbal medicine with potent anti-oxidant and anti-apoptotic properties, could protect testes from such doxorubicin injury.

EXPERIMENTAL APPROACH

Sprague-Dawley male rats (8 weeks old) were given vehicle, doxorubicin alone (3 mg kg(-1) every 2 days for three doses), EGb alone (5 mg kg(-1) every 2 days for three doses), or EGb followed by doxorubicin (each dose administered 1 day after EGb). At 7 days after the first drug treatment oxidative and apoptotic testicular toxicity was evaluated by biochemical, histological and flow cytometric analyses.

KEY RESULTS

Compared with controls, testes from doxorubicin-treated rats displayed impaired spermatogenesis, depleted haploid germ cell subpopulations, increased lipid peroxidation products (malondialdehyde), depressed antioxidant enzyme activities (superoxide dismutase, glutathione peroxidase and glutathione), reduced antioxidant enzyme expression (superoxide dismutase) and elevated apoptotic indexes (pro-apoptotic modulation of Bcl-2 family proteins, intensification of p53 and Apaf-1, release of mitochondrial cytochrome c, activation of caspase-3 and increase of terminal deoxynucleotidyl transferase nick-end labelling/sub-haploid cells), while EGb pretreatment effectively alleviated all of these doxorubicin-induced abnormalities in testes.

CONCLUSIONS AND IMPLICATIONS

These results demonstrate that EGb protected against the oxidative and apoptotic actions of doxorubicin on testes. EGb may be a promising adjuvant therapy medicine, potentially ameliorating testicular toxicity of this anti-neoplastic agent in clinical practice.

Inhibitory effect of ethylene glycol monoethyl ether on rat sperm motion

Ethylene glycol monoethyl ether (EGEE) is known to have testicular toxicity. To elucidate whether EGEE has any effect on sperm motion, especially in the case of short time exposure, we conducted a series of in vivo experiments with rats, as well as an in vitro study with rat sperm. Sperm from cauda epididymides and spermaducts was analyzed for the change in motion with a Hamilton-Thorne Sperm analyzer. Administration of EGEE at 600 mg/kg/d for five weeks significantly decreased total and progressive motility of sperm to 15-30% of controls, in both the cauda epididymis and the spermaduct. The time-course experiment using a single dose of 1,000 mg/kg showed that damage to sperm motion was evident at 12-24 h after EGEE administration. Addition of EGEE to the medium of sperm had no effect on its motion, but the metabolite ethoxyacetic acid showed a significant inhibitory effect. These results suggest that besides its toxicity to spermatogenesis, the metabolite of EGEE may also directly affect the motion of mature sperm.