Teratogenic effects of diphenyl diselenide in Wistar rats

Review of current and "omics" methods for assessing the toxicity (genotoxicity, teratogenicity and nephrotoxicity) of herbal medicines and mushrooms

ETHNOPHARMACOLOGICAL RELEVANCE

The increasing use of traditional herbal medicines around the world requires more scientific evidence for their putative harmlessness. To this end, a plethora of methods exist, more or less satisfying. In this post-genome era, recent reviews are however scarce, not only on the use of new "omics" methods (transcriptomics, proteomics, metabonomics) for genotoxicity, teratogenicity, and nephrotoxicity assessment, but also on conventional ones.

METHODS

The present work aims (i) to review conventional methods used to assess genotoxicity, teratogenicity and nephrotoxicity of medicinal plants and mushrooms; (ii) to report recent progress in the use of "omics" technologies in this field; (iii) to underline advantages and limitations of promising methods; and lastly (iv) to suggest ways whereby the genotoxicity, teratogenicity, and nephrotoxicity assessment of traditional herbal medicines could be more predictive.

RESULTS

Literature and safety reports show that structural alerts, in silico and classical in vitro and in vivo predictive methods are often used. The current trend to develop "omics" technologies to assess genotoxicity, teratogenicity and nephrotoxicity is promising but most often relies on methods that are still not standardized and validated.

CONCLUSION

Hence, it is critical that toxicologists in industry, regulatory agencies and academic institutions develop a consensus, based on rigorous methods, about the reliability and interpretation of endpoints. It will also be important to regulate the integration of conventional methods for toxicity assessments with new "omics" technologies.

Toxicological study of sodium selenite on fetal development and DNA fragmentation in liver cells of pregnant rats

The present study was carried out to evaluate the effects of sodium selenite on fetal development and DNA in liver of rats. Pregnant rats were divided into three groups: control group, group treated orally with 5 µg Se/kg body wt. and group treated orally with 10 µg Se/kg body wt. Dams were treated orally with sodium selenite from day 7 to 19 of gestation. Sodium selenite treatment revealed decrease in maternal body weight, reduction in fetal weight, length and number of viable fetuses, increased number of resorbed fetuses and post-implantation loss at the two doses tested. Fetal skeleton showed signs of developmental delay in skull and limbs of the treated groups. Sodium selenite treatment revealed significant reduction of placental and liver weights in treated dams. Sodium selenite-induced oxidative stress in liver tissue of rats as evidenced by increase in lipid peroxidation and glutathione peroxidase activity, while catalase was significantly decreased. Also, increase in DNA fragmentation, marked reduction of hepatic DNA content, and many histopathological changes in the liver were recorded. The results demonstrated that treatment of pregnant rats with sodium selenite at the toxic dosages chosen showed maternal and fetal toxicity that may be concerned with hepatic oxidative stress accompanied with DNA fragmentation and depletion of total DNA content.

The effects of maternal exposure to food additive E341 (tricalcium phosphate) on foetal development of rats

E341 (tricalcium phosphate) (TCP) is commonly used as a food additive and also as a nutritional supplement. To evaluate the possible developmental effects, female Wistar rats were treated with E341 (TCP) by oral gavage during pregnancy. There were three groups of each containing five rats. Rats in Groups I-III were fed with standard diet, oil and E341 (TCP) 175mg/kg body weight during gestation days (GD 0-20) respectively. We assessed foetal body lengths and weights and also made morphometric examination of placenta and umbilical cord. The placental weights of E341 (TCP) group (Group III) were found to be decreased statistically. According to skeletal stainings of foetuses, lengths of left ulna (28.3%), right femur (29.8%), left femur (34.9%) and diameter of the skull of y-axis were significantly decreased (12.3%) in E341 (TCP) treatment groups. There was an increase in trans-umbilical diameter in treatment group (14%). This is the first study in which developmental effects of E341 (TCP) have ever evaluated. The results suggest that prenatal development of rats during gestation is sensitive to E341 (TCP) exposure.

Repeated administration of diphenyl ditelluride induces hematological disorders in rats

In the present study, we investigated potential toxic effects of diphenyl ditelluride, as measured by biochemical and hematological parameters. Rats were given a daily dose of 0.3 micromol/kg diphenyl ditelluride by subcutaneous route and sacrificed at different times (24 and 48 h). Hepatic and renal TBARS levels were changed by diphenyl ditelluride exposure at the dose 0.9 micromol/Kg in rats. Diphenyl ditelluride exposure demonstrated an increase in AST (aspartate aminotransferase), ALT (alanine aminotransferase) and LDH (lactate dehydrogenase) activities. Plasma creatinine and urea levels increase after diphenyl ditelluride exposure. Diphenyl ditelluride also produced a significant decrease in plasma triglyceride and cholesterol levels. In contrast, this compound, at all doses tested, induced a marked increase in total leukocyte counts. The present study suggests that diphenyl ditelluride induces hematological disorders and provides evidence for renal and hepatic toxicity in rats.

Repeated administration of diphenyl diselenide to pregnant rats induces adverse effects on embryonic/fetal development

The present study was carried out to investigate the effects of diphenyl diselenide, (PhSe)(2), on embryo-fetal development. Dams were treated subcutaneously with 1.5, 3.0 and 6.0 mg/kg (PhSe)(2) from days 6 to 15 of pregnancy. After cesarean section at gestation day (GD) 20, external and skeletal abnormalities were evaluated. A decrease in maternal body weight gain was found in (PhSe)(2) groups, indicating maternal toxicity. There was a reduction in the fetal weight and in crown-rump (CR) length of fetuses at three doses tested. The occipito-nasal length decreased in fetuses from dams exposed to 3.0 mg/kg (PhSe)(2). Signs of delayed ossification in the skull, sternebrae and limbs were observed in all (PhSe)(2) groups, revealing a relation between morphological alterations and growth retardation in fetuses, but none of the changes appeared to be dose-dependent. Exposure of dams to (PhSe)(2) resulted in altered placental morphology that may have contributed to adverse reproductive outcomes. We concluded that (PhSe)(2) is toxic to dams and induces developmental delay of the fetal skeleton, but does not cause externally visible malformations in rat fetuses, in this experimental procedure.

Screening of potentially toxic chalcogens in erythrocytes

Previous literature reports have demonstrated that a number of human diseases, including inflammation and cancer, can be caused by environmental and occupational exposure to toxic compounds, via DNA damage, protein modifications, or lipid peroxidation. The present study was undertaken to screen the toxicity of a variety of chalcogens using erythrocytes as a model of cell injury. The toxicity of these compounds was evaluated via quantification of hemolysis and lipid peroxidation. The present investigation shows that diphenyl ditelluride and phenyl tellurides are toxic to erythrocytes. The organoselenium compounds were not toxic to erythrocytes even when tested at high concentrations and with a hematocrit of 45%. The hemolytic effect of tellurides was not positively correlated with thiobarbituric acid-reactive substance (TBARS) production suggesting that lipid peroxidation is not involved in the hemolysis provoked by organotellurium compounds. The results suggest that chalcogen compounds may be toxic to human erythrocytes, depending on their structure.

Adult male rats sub-chronically exposed to diphenyl diselenide: Effects on their progeny

The present study was conducted to evaluate the toxicity of diphenyl diselenide [(PhSe)2] exposure on the progeny of Wistar male rats. Male rats were exposed to (PhSe)2 subcutaneously for 4 weeks at the dose of 5.0 mg/kg and 8 weeks at the dose of 2.5 mg/kg, prior to mating with unexposed females. No lethality was noted in any group. At term of exposure period, 4-week exposed male rats presented significant decrease in the body weight. Sex organ weights were similar in (PhSe)2-exposed and control male groups. The number of implantation sites in females mated with males exposed to (PhSe)2 for 8 weeks was significantly higher than those of the respective control group. Male exposure to (PhSe)2, administered for 4 and 8 weeks, did not change fetal body weight. Gross examination of fetuses from 4- to 8-week exposed groups did not reveal the appearance of external anomalies. Examination of live fetuses for ossification centers did not show significantly difference between groups. No increase in the incidence of skeletal anomalies was observed in fetuses obtained from females impregnated with (PhSe)2-exposed males. The current study indicated that (PhSe)2 given sub-chronically (4 or 8 weeks) to male rats had no adverse effects on their progeny.

Evaluation of antioxidant activity and potential toxicity of 1-buthyltelurenyl-2-methylthioheptene

The aim of the present study was to evaluate pharmacological and toxicological properties of 1-buthyltelurenyl-2-methylthioheptene (compound 1). In vitro, compound 1 at 1 microM was effective in reducing lipid peroxidation induced by Fe/EDTA. Compound 1 presented neither thiol peroxidase nor thiol oxidase activity and did not change delta-ALA-D (delta-aminolevulinate dehydratase) activity (10-400 microM). Calculated LD(50) of compound 1, administered by oral route, was 65.1 micromol/kg. Rats treated with compound 1 did not reveal any motor impairment in the open field. Hepatic, renal and cerebral lipid peroxidation in treated rats did not differ from those in control rats. Conversely, 0.5 micromol/kg of compound 1 decreased lipid peroxidation in spleen. Delta-ALA-D activity in liver and spleen was inhibited in rats treated with the higher dose of compound 1 but no significant differences were detected in renal delta-ALA-D activity. AST (aspartate aminotransferase) and ALT (alanine aminotransferase) activities as well as urea and creatinine levels were increased by high doses of compound 1 (50-75 micromol/kg). Compound 1 induced a significant decrease in plasma triglyceride levels but none of the doses tested changed the cholesterol level. This is a promising compound for more detailed pharmacological studies involving organotellurium compounds.

Diphenyl diselenide changes behavior in female pups

Diphenyl diselenide, (PhSe)(2), is an organoselenium compound that affects a number of neuronal processes. The effect of maternal subcutaneous (s.c.) injection of 25 mg/kg (PhSe)(2) once daily during early postnatal development (from PND 1 to 21) was evaluated in offspring of Wistar rats. The physical and neural reflexes were recorded at pre-weaning period. The behavioral changes in the elevated plus-maze (EPM), open-field and rotarod tasks were performed in 28-day-old pups. Selenium brain status was significantly increased ( approximately 41%) in rat pups. Statistically significant decreases in body weight were observed during lactation period in male and female pups exposed to 25 mg/kg (PhSe)(2). There were no dose-related changes on landmarks indicative of physical and reflexologic parameters of development in rats. (PhSe)(2) induced a disinhibitory effect in EPM behavior according to gender. Specifically, exposure to (PhSe)(2) increased entries and duration in the open arms of the EPM in females but not in males. Locomotor activity and rearing increased by (PhSe)(2) exposure in both male and female offspring in the open field. Both groups were similar in response to motor coordination in the rotarod. We concluded that maternal (PhSe)(2) exposure during lactation increased selenium levels in the pup brain and caused changes on developmental and behavioral parameters of Wistar rat offspring.