Juan J. Sirvent

Influence of Chronic Exposure to Uranium on Male Reproduction in Mice

Relatively few data are available concerning the reproductive and developmental toxicity of uranium. The present study was designed to evaluate the reproductive effects of this metal in male Swiss mice. The animals were treated with uranyl acetate dihydrate at doses of 0, 10, 20, 40, and 80 mg/kg/day given in the drinking water for 64 days. To evaluate the fertility of the uranium-treated males, mice were mated with untreated females for 4 days. There was a significant but non-dose-related decrease in the pregnancy rate of these animals. Body weights were significantly depressed only in the 80 mg/kg/day group. Testicular function/spermatogenesis was not affected by uranium at any dose, as evidenced by normal testes and epididymis weights and normal spermatogenesis, whereas interstitial alterations and vacuolization of Leydig cells were seen at 80 mg/kg/day. The results of this investigation indicate that uranium does not cause any adverse effect on testicular function in mice at the concentrations usually ingested in the diet and drinking water, with a safety factor of more than 1000. However, although spermatogenesis was not affected by uranium administration, uranium produces a significant decrease in the pregnancy rate at 10, 20, 40, or 80 mg/kg/day.

Effects of exposure to BDE-99 on oxidative status of liver and kidney in adult rats

Little is known about the potential toxicity of polybrominated diphenyl ethers (PBDEs) on hepatic and renal tissues. In this study, we investigated the modifications in endogenous antioxidant capacity and oxidative damage in liver and kidney of rats by exposure to one of the most persistent PBDE congeners, the 2,2,4,4,5-pentabromodiphenyl ether (BDE-99). Adult male rats (10 per group) received BDE-99 by gavage at a single dose of 0, 0.6, and 1.2mg/kg body weight. Forty-five days after exposure, liver and kidney were removed and processed to examine the following oxidative stress (OS) markers: reduced glutathione (GSH), oxidized glutathione (GSSG), glutathione reductase (GR), glutathione peroxidase (GPx), glutathione-S-transferase (GST), superoxide dismutase (SOD), catalase (CAT), and thiobarbituric acid reactive substances (TBARS). In liver, BDE-99 significantly increased SOD activity, GSSG levels, and GSSG/GSH ratio, while GSH levels decreased. Moreover, CAT activity was only reduced at the highest BDE-99 dose. In kidney, CAT activity was significantly decreased, while GSSG/GSH ratio significantly increased following BDE-99 exposure at 1.2mg/kg body weight. Histological examination of tissues showed phagolysosomes in the kidneys of BDE-99-exposed rats. The results of this investigation suggest that acute oral BDE-99 exposure causes renal and liver impairment, being oxidative damage a potential mechanism for nephrotoxicity and hepatotoxicity.

Behavioral effects and oxidative status in brain regions of adult rats exposed to BDE-99

Polybrominated diphenyl ethers (PBDEs) are used as flame retardants. Although developmental neurotoxicity of PBDEs has been already investigated, little is still known about their potential neurotoxic effects in adulthood. In this study, we assessed the oxidative damage in brain sections and the possible behavioral effects induced by exposure to 2,2,4,4,5-pentabromodiphenyl ether (BDE-99). Adult male rats (10/group) received BDE-99 by gavage at single doses of 0, 0.6 or 1.2mg/kg/body weight. Forty-five days after exposure, the following behavioral tests were conducted: open-field activity, passive avoidance and Morris water maze. Moreover, cortex, hippocampus and cerebellum were processed to examine the following oxidative stress (OS) markers: reduced glutathione (GSH), oxidized glutathione (GSSG), glutathione reductase (GR), glutathione peroxidase (GPx), glutathione-S-transferase (GST), superoxide dismutase (SOD), catalase (CAT) and thiobarbituric acid reactive substances (TBARS). In cerebellum, BDE-99 significantly decreased SOD, CAT and GR activities at the highest BDE-99 dose. A decrease in CAT and SOD activities was also observed in cortex and hippocampus, respectively. In the behavioral tests, no BDE-99 effects were observed, while histopathological examination of the brain regions was normal. The current results show that the brain antioxidant capacity is affected by BDE-99 exposure, mainly in cerebellum. Oxidative damage could be a mechanism for BDE-99 neurotoxicity in adult rats.

Reproductive toxicity evaluation of vanadium in male mice

The reproductive toxicity of vanadium was studied in mice. Male Swiss mice were exposed to sodium metavanadate at doses of 0, 20, 40, 60, and 80 mg/kg per day given in the drinking water for 64 days. To evaluate the fertility of the vanadium-treated animals, males were mated with untreated females for 4 days. A significant decrease in the pregnancy rate was observed at 60 and 80 mg/kg per day of sodium. metavanadate. However, metavanadate did not reduce fertility in male mice at 20 and 40 mg/kg per day. Reproductive toxicity was measured by sperm count, sperm motility, organ weights, and histologic evaluation of the testes. Decreased body and epididymis weight was only observed in the 80 mg/kg per day group, while testicular weights were not altered by the treatment with all doses used. Sperm count was significantly decreased at 40, 60, and 80 mg/kg per day, but the sperm motility was unaffected. Histopathological examination revealed that the testes were normal and that the epididymis of treated male mice contained normal appearing sperm. The no observed adverse effect level (NOAEL) was 40 mg/kg per day. Consequently, vanadium would not cause any adverse effect on fertility or testicular function in male mice at the concentrations usually ingested by humans through the diet and drinking water.

Nephrotoxicity of simultaneous exposure to mercury and uranium in comparison to individual effects of these metals in rats

Both inorganic mercury and uranium are known nephrotoxicants in mammals. In this study, the renal toxicity of a concurrent exposure to inorganic mercury and uranium was compared with the nephrotoxic effects of the individual metals in a rat model. Eight groups of rats, 10 animals per group, were subcutaneously given a single administration of mercuric chloride (HgCl2, 0.34 mg/kg and 0.68 mg/kg), uranyl acetate dihydrate (UAD, 2.5 mg/kg and 5 mg/kg), or combinations of both compounds at the same doses. A ninth group of rats received sc injections of 0.9% saline and was designated as the control group. Necrosis of proximal tubules, which was observed in all experimental groups, was the most relevant morphologic abnormality. Marked changes, which were remarkably greater than those induced by the individual elements, were noted in some urinary parameters in the groups concurrently exposed to HgCl2 and UAD. It could be an indicator of a synergistic interaction between mercury and uranium. In contrast, compared with the urinary levels found after individual administration of the highest doses of mercury and uranium, significant reductions in the urinary concentrations of these elements were noted following simultaneous exposure to both metals. At these doses, the reduction in the urinary metal excretion was also accompanied by significant decreases in the renal content of mercury and uranium. Whereas the results of some parameters pointed out a possible synergistic interaction between mercury and uranium, other measures hinted that an antagonistic interaction between these elements is also present.

Sulfasalazine induced oxidative stress: A possible mechanism of male infertility

The mechanism of action of sulfasalazine (SASP) in male infertility is not well elucidated. For it, an oxidative stress-like mechanism inductor of infertility was hypothesized. Adult male Sprague-Dawley rats (20/group) were orally administered 0, 300, and 600mg SASP/kg body weight for 14 days. One-half of animals in each group remained an additional period of 14 days without treatment. SASP induced a significant decrease of superoxide dismutase (SOD) and glutathione reductase (GR) at the highest dose in both testis and epididymis. GR remained altered in these tissues within the recovery period. However, an increase in SOD was noted in epididymis. An increase in thiobarbituric acid-reactive substances (TBARS) was noted in all SASP-treated groups. In epididymis, catalase (CAT) significantly increased at 600mg/(kgday). These results suggest that SASP induces oxidative stress, which in turn might act as a possible mechanism of male-induced infertility.

Lipid peroxidation and antioxidant status in kidney and liver of rats treated with sulfasalazine

Sulfasalazine (SASP) is a drug commonly used in the treatment of inflammatory bowel diseases (IBD). In this study, the changes in endogenous antioxidant capacity and oxidative damage in liver and kidney of SASP-treated rats were investigated. Adult male Sprague-Dawley rats were orally given 0, 300, or 600 mg SASP/kg body weight for 14 days. One half of the animals in each group remained 14 additional days without SASP treatment. At the end of the experimental period, rats were euthanized and liver and kidney were removed. In both organs, the following stress markers were determined: reduced glutathione (GSH), oxidized glutathione (GSSG), glutathione reductase (GR), glutathione peroxidase (GPx), glutathione-S-transferase (GST), superoxide dismutase (SOD), catalase (CAT), and thiobarbituric acid-reactive substances (TBARS). Moreover, histological examination of kidneys showed phagolysosomes after 14 days of SASP withdrawal. A dropsical degeneration was also observed in renal tissue. Oral SASP administration induced a significant increase in TBARS levels in both liver and kidney. After 2 weeks without SASP administration, a recovery of these levels was noted. SOD activity was significantly reduced, while CAT activity significantly increased at 600 mg SASP/(kg day). In kidney, GPx activity significantly increased, while GST activity and GSH levels were significantly reduced at 600 mg SASP/(kg day). These results suggest that in male rats, oxidative damage can be a mechanism for nephro- and hepatotoxicity related with SASP treatment.

Oral subchronic exposure to silver nanoparticles in rats

Because of their extremely small size, silver nanoparticles (AgNPs) show unique physical and chemical properties, with specific biological effects, which make them particularly attractive for being used in a number of consumer applications. However, these properties also influence the potential toxicity of AgNPs. In this study, we assessed the potential toxic effects of an inxa0vivo oral sub-chronic exposure to polyvinyl pyrrolidone coated AgNPs (PVP-AgNPs) in adult male rats. We also assessed if oral PVP-AgNPs exposure could alter the levels of various metals (Fe, Mg, Zn and Cu) in tissues. Rats were orally given 0, 50, 100 and 200xa0mg/kg/day of PVP-AgNPs. Silver (Ag) accumulation in tissues, Ag excretion, biochemical and hematological parameters, metal levels, as well as histopathological changes and subcellular distribution following PVP-AgNPs exposure, were also investigated. After 90 days of treatment, AgNPs were found within hepatic and ileum cells. The major tissue concentration of Ag was found in ileum of treated animals. However, all tissues of PVP-AgNPs-exposed animals showed increased levels of Ag in comparison with those of rats in the control group. No harmful effects in liver and kidney, as well as in biochemical markers were noted at any treatment dose. In addition, no hematological or histopathological changes were found in treated animals. However, significant differences in Cu and Zn levels were found in thymus and brain of PVP-AgNPs-treated rats.

Effects of oral exposure to silver nanoparticles on the sperm of rats

It has been demonstrated that exposure to silver nanoparticles (AgNPs) can induce toxicological effects in rodents. In this study, we investigated whether sub-chronic oral exposure to different doses of polyvinil pyrrolidone (PVP)-coated AgNPs (PVP-AgNPs) (50, 100 and 200mg/kg/day) could induce harmful effects on epididymal sperm rat parameters. Sperm motility, viability and morphology were examined. Moreover, a histological evaluation of testis and epididymis was also performed. High doses of PVP-AgNPs showed higher sperm morphology abnormalities, while a progressive, but not significant effect, was observed in other sperm parameters. The current results suggest that oral sub-chronic exposure to PVP-AgNPs induces slight toxicological effects in sperm rat parameters.

Effects on the reproductive system of young male rats of subcutaneous exposure to n-butylparaben

This study was aimed at determining whether an inxa0vivo subcutaneous exposure to n-butylparaben (n-ButP) during one complete spermatogenic cycle could be harmful to the reproductive system of young male rats. Animals were subcutaneously given 0, 150, 300 and 600xa0mg/kg/day of n-ButP with vehicle (peanut oil). Body and organ weights, n-ButP excretion, biochemical parameters, sperm and spermatid count, sperm motility, viability, maturity and morphology were examined. Results showed that after a completed spermatogenic cycle, although n-ButP did not induce dose-related changes in the different biochemical parameters, a significant decrease of triacylglicerides (TAG) -due to the vehicle-was found. Furthermore, no effects of n-ButP on body weight gain and relative organ weight changes were noted. Regarding sexual organs, prostate relative weight was significantly increased at the high dose of n-ButP. On the other hand, a significant increase of abnormal sperm morphology due to n-ButP exposure, accompanied by different alterations in sexual organs histopathology, was found. The current results indicate that subcutaneous exposure of n-ButP in young male rats induced toxic effects on the reproductive system, which could affect the capacity of fertilization of animals.