Genotoxicity of the some selective estrogen receptor modulators: a review

Clomiphene Citrate Administered in Periconception Phase Causes Fetal Loss and Developmental Impairment in Mice

Clomiphene citrate is a common treatment for ovulation induction in subfertile women, but its use is associated with elevated risk of adverse perinatal outcomes and birth defects. To investigate the biological plausibility of a causal relationship, this study investigated the consequences in mice for fetal development and pregnancy outcome of periconception clomiphene citrate administration at doses approximating human exposures. A dose-dependent adverse effect of clomiphene citrate given twice in the 36 hours after mating was seen, with a moderate dose of 0.75 mg/kg sufficient to cause altered reproductive outcomes in 3 independent cohorts. Viable pregnancy was reduced by 30%, late gestation fetal weight was reduced by 16%, and ∼30% of fetuses exhibited delayed development and/or congenital abnormalities not seen in control dams, including defects of the lung, kidney, liver, eye, skin, limbs, and umbilicus. Clomiphene citrate also caused a 30-hour average delay in time of birth, and elevated rate of pup death in the early postnatal phase. In surviving offspring, growth trajectory tracking and body morphometry analysis at 20 weeks of age showed postweaning growth and development similar to controls. A dysregulated inflammatory response in the endometrium was observed and may contribute to the underlying pathophysiological mechanism. These results demonstrate that in utero exposure to clomiphene citrate during early pregnancy can compromise implantation and impact fetal growth and development, causing adverse perinatal outcomes. The findings raise the prospect of similar iatrogenic effects in women where clomiphene citrate may be present in the periconception phase unless its use is well-supervised.

Therapeutic benefit of ursodeoxycholic acid in tamoxifen-induced hepatotoxicity in Wistar rats

Background. The clinical use of tamoxifen (TAM) may cause hepatotoxicity. Ursodeoxycholic acid (UDCA) has promising liver protective activity. This study assessed the protective effect of UDCA on TAM-induced hepatotoxicity in rats.Material and methods. Thirty five adult female Wistar rats were grouped into 7 of n=5/group. The rats were treated for 10 days as follows: Group 1: Water (10 mL/kg/day; placebo control) per oral [p.o], group 2: Ethanol 1% (1mL/kg/day; vehicle control) intraperitoneally (i.p), group 3: UDCA (40 mg/kg/day/p.o) and group 4: TAM (45 mg/kg/day) i.p. Groups 5-7 were pretreated with UDCA (10, 20 and 40 mg/kg), before daily treatment with TAM (45 mg/kg/day) i.p, respectively. On day 11, blood samples were collected and assessed for serum liver biomarkers. Liver samples were evaluated for oxidative stress markers and histology.Results. Significantly (p<0.05) decreased body weight and significantly (p<0.01) increased liver weight occurred in TAM- treated rats when compared to placebo control. TAM significantly (p<0.001) increased serum alkaline phosphatase, lactate dehydrogenase, gamma-glutamyl transferase, aminotransferases, bilirubin, high density lipoprotein cholesterol levels and liver malondialdehyde levels when compared to control. TAM significantly (p<0.001) decreased liver glutathione, catalase, glutathione peroxidase, superoxide dismutase, serum total protein, albumin total cholesterol, low density lipoprotein cholesterol and triglyceride levels when compared to control. Steatosis and necrotic changes occurred in TAM-treated rats. UDCA pretreatment significantly prevents TAM-induced changes in serum biochemical markers, and oxidative stress indices in a dose-related fashion when compared to TAM. UDCA prevents TAM-induced changes in liver histology.Conclusion. UDCA may be clinically effective for TAM associated hepatotoxicity.

Genotoxic and mutagenic studies of teratogens in developing rat and mouse

In this review, genotoxic and mutagenic effects of teratogenic chemical agents in both rat and mouse have been reviewed. Of these chemicals, 97 are drugs and 33 are pesticides or belong to other groups. Large literature searches were conducted to determine the effects of chemicals on chromosome abnormalities, sister chromatid exchanges, and micronucleus formation in experimental animals such as rats and mice. In addition, studies that include unscheduled DNA synthesis, DNA adduct formations, and gene mutations, which help to determine the genotoxicity or mutagenicity of chemicals, have been reviewed. It has been estimated that 46.87% of teratogenic drugs and 48.48% of teratogenic pesticides are positive in all tests. So, all of the teratogens involved in this group have genotoxic and mutagenic effects. On the other hand, 36.45% of the drugs and 21.21% of the pesticides have been found to give negative results in at least one test, with the majority of the tests giving positive results. However, only 4.16% of the drugs and 18.18% of the pesticides were determined to give negative results in the majority of the tests. Among tests with major negative results, 12.50% of the teratogenic drugs and 12.12% of the teratogenic pesticides were negative in all conducted tests.

Potential anti-genotoxic effect of sodium butyrate to modulate induction of DNA damage by tamoxifen citrate in rat bone marrow cells

Sodium butyrate (SB) is one of the histone deacetylase inhibitors (HDACi's) that is recently evidenced to have a prooxidant activity and an ability to reduce hydrogen peroxide-induced DNA damage. Since the majority of estrogen receptor positive breast cancer patients are treated with tamoxifen citrate (TC), which exerts well established oxidative and genotoxic effects, thus the basic objective of this study is to determine whether SB could ameliorate or curate tamoxifen citrate-induced oxidative DNA damage and genotoxic effect in vivo through up-regulation of some antioxidant enzymes. The individual and combined effects of SB and TC have been examined on rat bone marrow cells, using Micronucleus assays (MN), Comet assay, DNA fragmentation, expression of some antioxidant genes using Real time-PCR and finally, oxidative stress analysis. SB significantly increased the mitotic activity (P < 0.05), while TC induced marked micronuclei and oxidative DNA damage, in the SB post-treatment group, the combination of SB (300 mg/kg) and TC (40 mg/kg) was able to decrease the induction of MN and oxidative DNA damage through up-regulation of Cat, Sod and Gpx1 genes significantly at (P < 0.05) more efficiently than that in the SB pre-treatment one. Therefore, we postulate that SB can be used therapeutically in combination with TC treatment to modulate TC genotoxic effect by reducing its oxidative stress, and thus being an appropriate agonist agent to combine with TC than each compound alone.