The Future of the Teratogenicity Testing.

The purpose of this review is to examine the importance, possible advantages and disadvantages of teratogenicity tests, and their future. For this purpose, numerous sources have been scanned in the field of teratogenicity. Although there are many methods related to teratogenic studies and very important studies have been made in this field, there are still serious deficiencies. There are advantages and disadvantages of in vitro and in vivo classical tests that have been used so far. The current status of in vivo tests is a matter of debate, especially due to the use of experimental animals. However, in vitro tests that do not perform the distribution and metabolism of chemicals also raise doubts in determination of teratogenicity. Despite the modern approaches of molecular biology and genetics and the best diagnostic techniques, the real cause of more than half of congenital diseases is still not understood. In this sense, the importance and necessity of teratogenic tests are understood once again. It is necessary to develop faster, reliable, and inexpensive techniques to replace traditional in vivo tests. It is important to disseminate harmless and reliable imaging techniques such as micro-CT. The use of European Center for the Validation of Alternative Methods (ECVAM) scientifically validated and approved in vitro tests such as embryonic stem cell test (EST), micro mass test (MM), and whole embryo culture (WEC) tests in routine screening can provide a solution in a shorter time than the classical tests. Improving these tests and developing new tests can help to solve the problem permanently.

A new variant of the ectodysplasin A receptor death domain gene associated with anhidrotic ectodermal dysplasia in a Turkish family and its simple diagnosis by restriction fragment length polymorphism.

Ectodermal dysplasia (ED), which exhibits a wide range of clinical symptoms, may be classified into three major types: hypohidrotic, anhidrotic, and hidrotic. A male child (proband) showing anhidrotic dysplasia was used as the subject of this study. The biopsy of the big toe revealed that the male child had no sweat glands. Genetic analysis of the patient revealed a mutation caused by a homozygous nucleotide substitution in the EDAR-associated death domain (EDARADD) (rs114632254) gene c.439G>A (p.Gly147Arg). Phenotypically, his teeth were sharp, but eight teeth were missing (oligodontia). The patient had normal nails with dry skin, sparse hair, everted lower lip vermilion, hyperpigmented eyelids, and abnormal nasal bridge morphology around the eyes. There is also a homozygous dominant (healthy) female and a heterozygous male in this family, who are cousins (aunt children) to the heterozygous parents. The daughter of the patient was also heterozygous. This mutation represents homozygous recessive inheritance, which we describe for the first time. Furthermore, we demonstrated that this genetic disorder can be readily diagnosed using the restriction fragment length polymorphism (RFLP) method after digestion with MnII restriction endonuclease.

In vitro screening of genotoxicity and mutagenicity of pyriproxyfen in human lymphocytes and Salmonella typhimurium TA98 and TA100 strains.

Pyriproxyfen (PPX) is a pesticide/larvicide used to increase productivity in agriculture against insects by inhibiting development of insects' larvae. In this study, cytotoxic, genotoxic, and mutagenic effects of PPX were investigated in human peripheral lymphocytes and Salmonella typhimurium strains by performing chromosomal aberration, micronucleus (MN) tests, and Ames test, respectively. For the chromosome aberration (CA) and MN methods, blood from four healthy donors (two men and two women, nonsmokers) were used. Two hundred microliters of blood was inoculated into PbMax medium and prepared according to International Guidelines. For the Ames test, S. typhimurium TA98 and TA100 strains were used to detect frameshift and base pair substitution mutagens, respectively. PPX induced both the CA percentage and MN frequency in human peripheral lymphocytes and exhibited cytotoxic effects. In addition, it showed a mutagenic effect at all doses in TA98 and TA100 strains in the presence of S9mix; however, no such effect was observed in the absence of S9mix. According to the obtained results, it can be said that PPX has genotoxic and mutagenic potentials.

Genotoxic potential of different nano-silver halides in cultured human lymphocyte cells.

Most antibacterial applications in nanotechnology are carried out using silver nanoparticles (AgNPs). However, there is a dearth of information on the biological effects of AgNPs on human blood cells. In this study, the cytotoxic and genotoxic potentials of ionic silver (Ag+), AgNP, silver bromide (AgBr), silver chloride (AgCl), and silver iodide (AgI) were evaluated through chromosome aberration (CA) test and cytokinesis-blocked micronucleus (CBMN) test in human cultured lymphocytes in vitro. Furthermore, the potential damages that can cause to DNA were evaluated through alkaline single cell gel electrophoresis (Comet) assay on isolated lymphocytes. The results showed that AgNPs exerted cytotoxic effects by reducing the cytokinesis-block proliferation index and mitotic index at 24 and 48 h. AgNPs also increased micronucleus (MN) formation at both exposure times in the cultured cells. Meanwhile, AgCl had no genotoxic effects on the human lymphocyte cultured cells but had a cytotoxic effect at high doses. AgNP, Ag+, AgBr, and AgI caused substantial DNA damage by forming DNA strand breaks. They may also have clastogenic, genotoxic and cytotoxic effects on human lymphocyte cells. Based on the foregoing findings, silver nanomaterials may have genotoxic and cytotoxic potentials on human peripheral lymphocytes in vitro.

Chemical and biological characteristics of propolis from Apis mellifera caucasica from the Ardahan and Erzurum provinces of Turkey: a comparative study.

The aim of this study was to compare the biological activities of ethanolic propolis extracts of Apis mellifera caucasica obtained from Ardahan and Erzurum provinces of Turkey. Samples were tested for antioxidant, anticytotoxic, anticarcinogenic, antibacterial, and antifungal potentials using different techniques. Propolis samples from the two provinces had different mineral and organic compositions related to their geographical origin. The ferric reducing antioxidant power (FRAP) test showed superiority of Ardahan propolis over the Erzurum. Regardless of origin and the presence of mitomycin C in the culture medium, propolis enhanced human peripheral lymphocyte viability, which depended on the duration and propolis concentration. Antiperoxidative activity on MCF-7 breast cancer cells was concentration-dependent. Erzurum propolis showed the highest anticarcinogenic activity at the concentrations of 62.5 µg/mL and 125 µg/ mL, which dropped at higher concentrations. All propolis samples also showed antibacterial activity against the tested human pathogens similar to ampicillin and penicillin controls, except for Pseudomonas aeruginosa. However, they did not exert any antifungal activity against Candida albicans and Yarrowia lipolytica. In conclusion, propolis samples from both provinces showed promising biological activities, but further research should focus on finding the right concentrations for optimal effect and include the cell necrosis pathway to get a better idea of the anticarcinogenic effects.

The Effect of Five Single Nucleotide Polymorphisms on Hb F Variation of ß-Thalassemia Traits and Hematologically Normal Individuals in Southeast Turkey.

ß-Thalassemia (ß-thal) is caused by deficiency of ß-globin chain synthesis and leads to the accumulation of unstable globin chain production. This results in a higher Hb F level in order to neutralize the excess α chains. In addition, γ-globin gene expression, due to genetic factors after birth, leads to increased Hb F levels in adulthood [hereditary persistence of fetal hemoglobin (Hb) (HPFH)]. In this study, the relationship between ß-thal trait and individuals with suspected HPFH and a control group was investigated in Adiyaman, Turkey. Single nucleotide polymorphism (SNP) analyses were performed in five different polymorphic regions using real-time polymerase chain reaction (qPCR) methods [rs4671393 (G>A), rs766432 (A>C), rs9402686 (G>A), rs28384513 (T>G), rs1609812 (A>G)]. No significant difference was found between the control and ß-thal group in the codominant inheritance model in the rs1609812 (A>G) polymorphism region only, while all the other polymorphic regions were found to be statistically significant. It was found that different genotype models increased Hb F levels between 1.6- and 3.06-fold in four studied polymorphic regions [rs4671393 (G>A), rs766432 (A>C), rs9402686 (G>A), rs28384513 (T>G)]. All of the polymorphic regions increased the Hb F levels from 1.86- to 24.76-fold, except rs9402686 (G>A) and rs28384513 (T>G) over dominant and rs1609812 (A>G) codominant inheritance models. The AC and AA genotypes increased Hb F levels in the B-cell CLL/lymphoma 11 A haplotype studies. It was determined that both haplotypes 2 and 4 increased Hb F levels. As a result, SNPs strongly affect the Hb F levels in both healthy individuals and ß-thal trait.

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.

Methodology of Genotoxic and Teratogenic Studies in Rats.

The genotoxicity methods applied to rats are tests that can detect any damage, including changes in the number of chromosomes or in the structure of chromosomes, and nucleotide changes with structural abnormality in the DNA of animal cells. However, the method of teratogenicity is used to detect the effects of chemicals which cause congenital defects in living organisms. This study contains information about the effectiveness, reliability, ways of application, and methodology of genotoxic and teratogenic methods applied in vivo in rats.

The relationship between the variations in Gγ and Aγ promotors and the Hereditary Persistence of Fetal Hemoglobin (HPFH).

In the present study, sixty-two samples that have 1.5% and upper level of fetal hemoglobin (HbF), were examined to investigate the relationship between HbF level and non-deletional mutations in both Gγ (G gamma) globin (HBG2) and Aγ (A gamma) globin (HBG1) genes. Four variations were observed in the promotor of Gγ gene, which are -158C/T, -309A/G, -369C/G, and -567T/G. Also, four variations were observed in the 5'-UTR (untranslated regions) and promotor of Aγ gene, which are +25G/A, -369G/C, -499T/A, and -588G/A. One -222/-225 AGCA del homozygous and six variations as heterozygous in A gamma globin gene promotor region were also observed. The results of the current study suggested that there was a significant relationship between high HbF levels and two variations (-309A/T and -369C/G) in Gγ gene promotor. Additionally, a significant relationship between two variations (+25G/A and -499T/A) in Aγ gene promotor was also observed. Furthermore, the persons who carry these variations with high levels of HbF indicated that there might be a haplotype effect between these variations.

Investigations on the effects of etoxazole in the liver and kidney of Wistar rats.

Pesticides are used to protect crops and to eliminate pests, though non-target organisms such as mammals are also affected from their usage. Etoxazole (organoflourine pesticide) is an acaricide used to combat spider mites which are the parasites of various crops. The present study aims to investigate the effects of etoxazole on the level of MDA (malondialdehyde) and activities of CAT (catalase), GPx (glutathione peroxidase), and AChE (acetylcholinesterase) in liver and kidney tissues of Wistar rats (Rattus norvegicus var. albinos). Rats received etoxazole intraperitoneally with doses of 2.2, 11, and 22 mg/kg b.w./day for 21 days. Control rats received the same volume of the serum physiologic. Following etoxazole exposures, activities of CAT, GPx, and AChE in the liver and kidney of rats significantly decreased at all doses compared to control group. Oppositely, MDA levels in these tissues increased significantly at all doses following etoxazole exposures. The present study demonstrated that etoxazole, at all doses, had toxic effects in the liver and kidney parameters, suggesting their possible use as effective biomarkers in determining the toxic effects of etoxazole. This may suggest that these biomarkers could also be used as a tool to monitor pesticide-affected areas before severe toxic effects begin in non-target animals and humans.

Polymorphisms in human telomerase reverse transcriptase (hTERT) gene and susceptibility to gastric cancer in a Turkish population: Hospital-based case-control study.

Erosion of telomeres, tandem nucleotide repeats (TTAGGG)n that cap the end of eukaryotic chromosomes, has been related with carcinogenesis. The human telomerase reverse transcriptase (hTERT) gene is encoded the rate-limiting catalytic subunit of the telomerase complexes, which is essential for the protection of telomeric DNA length and chromosomal stability. The purpose of this study was to examine the effect of four functional single nucleotide polymorphisms (SNPs) of hTERT (rs2736109 G>A, rs2735940 T>C, rs2853669 A>G and rs2736100 T>G) on susceptibility to gastric cancer (GC) in Turkish population. The genotype frequency of hTERT rs2736109 G>A, rs2735940 T>C, rs2853669 A>G and rs2736100 T>G polymorphisms were determined by using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and TaqMan methods in 104 subjects with GC and 209 healthy control subjects. We found that hTERT rs2736109 G>A (AA+AG vs. GG OR=1.68 95% CI=1.01-2.81, P=0.04), rs2735940 T>C (CC vs. CT+TT: OR=2.53 95% CI=1.01-6.13, P=0.03), and rs2736100 T>G (TT vs. TG+GG: OR=2.27 95% CI=1.23-4.17, P=0.006) polymorphisms were associated with risk of GC. In the haplotype analysis, hTERT Grs2736109/Trs2735940/Ars2853669/Grs2736100 haplotype was also related with an increased risk of GC (OR=1.75; 95% CI: 1.05-2.93, P=0.03). Because this is the first study regarding the hTERT rs2736109 G>A, rs2735940 T>C, rs2853669 A>G and rs2736100 T>G polymorphisms and the risk of GC susceptibility in the literature, further independent studies are needed to verify our results in a larger sample sizes, as well as in patients of different populations.

Genotoxicity and cytotoxicity of copper oxychloride in cultured human lymphocytes using cytogenetic and molecular tests.

The genotoxicity of copper oxychloride was investigated in human lymphocytes using chromosome aberration (CA) and micronucleus (MN) tests and the randomly amplified polymorphic DNA-polymerase chain reaction technique. The lymphocytes were treated with 3, 6, and 12 µg/mL of copper oxychloride for 24 and 48 h. Copper oxychloride increased CA and abnormal cells in a dose-dependent manner. The frequency of MN and micronucleated binuclear cells also increased at all concentrations and treatment periods. However, copper oxychloride cytotoxicity, observed through lower mitotic and nuclear division index, was significantly lower only at the higher concentrations (6 and 12 µg/mL). Copper oxychloride increased the polymorphic bands and decreased genomic template stability. In conclusion, in this study it was confirmed that copper oxychloride has genotoxic potential for human lymphocytes in vitro. Additionally, caution is advised for its use as a fungicide, because it may increase the risk of exposure through the food chain.

Effect of p53 Arg72Pro polymorphism on the induction of micronucleus by aflatoxin B1 in in vitro in human blood lymphocytes.

Aflatoxin B1 (AFB1) is a class 1 carcinogen produced by Aspergillus flavus and Aspergillus parasiticus that can contaminate a variety of food substances, the liver being its target organ. A common p53 Arg72Pro polymorphism resulting in the substitution of an arginine amino acid by proline amino acid in the transactivating domain has been demonstrated to affect p53 function. The aim of this study is to investigate association between p53 Arg72Pro polymorphism and the frequencies of spontaneous and AFB1-induced DNA damage in peripheral blood lymphocytes from 100 healthy individuals in Turkish population. In vitro cytokinesis-blocked micronucleus (CBMN) assay was used to detect the spontaneous and AFB1-induced DNA damage whereas, genotyping of p53 Arg72Pro polymorphism was carried out by using a polymerase chain reaction restriction fragment length polymorphism assay. During 68 h incubation time, lymphocytes treated with AFB1 (1.56 µg/mL) and S9 mix for a total of 3 h (48-51 h). Treatment of the lymphocytes with AFB1 significantly increased the overall frequencies of micronucleus (MN) when compared to untreated cultures (1.23 ± 0.05 versus 0.55 ± 0.02; p <0.001). Moreover, genotype analysis revealed a statistically significant association between Pro/Pro genotype of p53 Arg72Pro polymorphism and increased frequencies of MN both spontaneous and AFB1-induced cultures when compared Arg/Arg genotype (0.69 ± 0.19 versus 0.46 ± 0.13, p < 0.001; 1.59 ± 0.65 versus 1.01 ± 0.41 p < 0.001; respectively). Our data indicate that p53 Arg72Pro polymorphism plays a significant role in human sensitivity to the genotoxic effects of AFB1. Further investigations in larger sample size and with different ethnic origins as well as including more functional single nucleotide polymorphisms might lead to the identification of novel genetic factors responsible for susceptibility to human carcinogens such as AFB1.

Sex-related effects of imidacloprid modulated by piperonyl butoxide and menadione in rats. Part II: genotoxic and cytotoxic potential.

Despite its intended use, imidacloprid causes genotoxic and cytotoxic effects in mammals, especially in the presence of metabolic activation systems. The aim of this study was to determine to which extent these effects are sex related and how its metabolism modulators piperonyl butoxide and menadione affect its toxicity. Male and female Sprague-Dawley rats were injected with the intraperitoneal LD50 dose of imidacloprid alone (170 mg/kg) or pretreated with piperonyl butoxide (100 mg/kg) and menadione (25 mg/kg) for 12 and 24 h. Structural chromosome aberrations, abnormal cells and mitotic index were determined microscopically in bone marrow cells. Male rats showed susceptibility to the genotoxic effects of imidacloprid. Piperonyl butoxide was effective in countering this effect only at 24 h, whereas menadione exacerbated imidacloprid-induced genotoxicity. Piperonyl butoxide and menadione pretreatments increased the percentage of structural chromosome aberrations and abnormal cells in females. Imidacloprid decreased the mitotic index, whereas pretreatment with piperonyl butoxide and menadione showed improvement in both sexes. We believe that CYP450-mediated metabolism of imidacloprid is under the hormonal control and therefore that its genotoxicity is sex related. Piperonyl butoxide pretreatment also showed sex-related modulation. The hormonal effects on imidacloprid biotransformation require further investigation.

A functional HOTAIR rs920778 polymorphism does not contributes to gastric cancer in a Turkish population: a case-control study.

An aberrant up-regulation of HOX transcript antisense intergenic RNA (HOTAIR), a long non-coding RNA (lncRNA), is associated with human cancers including gastric cancer (GC) and worse clinicopathological features. A naturally occurring functional single nucleotide polymorphism (SNP) rs920,778 (C→T) in the intronic enhancer of HOTAIR gene has been demonstrated to affect HOTAIR expression and cancer susceptibility. To investigate the association of the HOTAIR rs920778 polymorphism on the risk of GC susceptibility in Turkish population, a hospital-based case-control study was carried out consisting of 104 GC and 209 healthy control subjects matched on age and gender. The genotype frequency of HOTAIR rs920778 polymorphism was determined by using TaqMan Real-Time Polymerase Chain Reaction. No statistically significant differences were found in the allele or genotype distributions of the HOTAIR rs920778 polymorphism among GC and healthy control subjects (P > 0.05). Our results demonstrate that the HOTAIR rs920778 polymorphism has not been in any major role in genetic susceptibility to gastric carcinogenesis, at least in the population studied here. Independent studies are needed to validate our findings in a larger series, as well as in patients of different ethnic origins.

The effects of cyfluthrin on some biomarkers in the liver and kidney of Wistar rats.

Pesticides can cause oxidative stress resulting to deleterious effects in animal metabolisms. Cyfluthrin is a synthetic pyrethroid used worldwide to protect crops and to eliminate pests. Thus, the aim of this study was to investigate the effects of the cyfluthrin on the level of malondialdehyde (MDA) and activities of catalase (CAT), glutathione peroxidase (GPx), and acetylcholinesterase (AChE) in the liver and kidney of Wistar Albino Sprague Dawley rats (Rattus norvegicus var. albinos) following intraperitoneal treatment of cyfluthrin (1.2, 12, and 120 mg/kg b.w./day) for 21 days. Comparisons were made with two control solutions named as serum physiologic and solvent in which cyfluthrin was dissolved. CAT activity in the liver and kidney of rats did not change after the lowest cyfluthrin treatment, while its activity significantly decreased at the higher doses. In general, cyfluthrin significantly decreased the activity of GPx in the liver and kidney at all doses, while MDA levels in the liver increased at all doses. Cyfluthrin significantly decreased AChE activity in the liver of rats at all doses, while this was true at the highest dose for the kidney. This study showed that the studied biomarkers were effective in determining the toxic effects of cyfluthrin. Thus, they should be used to monitor pesticide-affected areas before untargeted animals, including humans who suffer from the use of pesticides.

In vitro investigation of the genotoxic and cytotoxic effects of thiacloprid in cultured human peripheral blood lymphocytes.

Thiacloprid, a neonicotinoid insecticide, is widely used for controlling various species of pests on many crops. The potential genotoxic effects of thiacloprid on human peripheral blood lymphocytes (PBLs) were investigated in vitro by the chromosome aberrations (CAs), sister chromatid exchanges (SCEs), and cytokinesis-block micronucleus (MN) assays. The human PBLs were treated with 75, 150, and 300 µg/mL thiacloprid in the absence and presence of an exogenous metabolic activator (S9 mix). Thiacloprid increased the CAs and SCEs significantly at all concentrations (75, 150, and 300 µg/mL) both in the absence and presence of the S9 mix and induced a significant increase in MN and nucleoplasmic bridge formations at all concentrations for 24 h and at 75 and 150 µg/mL for 48-h treatment periods in the absence of the S9 mix; and at all concentrations in the presence of the S9 mix when compared with the control and solvent control. Thiacloprid was also found to significantly induce nuclear bud (NBUD) formation at 300 µg/mL for 24 h and at 150 µg/mL for 48-h treatment times in the absence of the S9 mix and at the two highest concentrations (150 and 300 µg/mL) in the presence of the S9 mix. Thiacloprid significantly decreased the mitotic index, proliferation index, and nuclear division index for all concentrations both in the absence and presence of the S9 mix.

The genotoxic and antigenotoxic effects of Salvia fruticosa leaf extract in human blood lymphocytes.

The aim of this study was to investigate the genotoxic and antigenotoxic effects of Salvia fruticosa (Sf) leaf extract with the absence and presence of S9 mix using sister chromatid exchange (SCE), chromosome aberration (CA) and micronucleus (MN) formation test systems in human peripheral blood lymphocytes (HPBLs) that were treated with 1.5-, 3.0- and 6.0-µL/mL concentrations for 24- and 48-hour treatment periods. The cytotoxicity of Sf leaf extract was also investigated by calculating the mitotic index (MI), proliferation index (PI) and nuclear division index (NDI). In the absence of S9 mix, Sf leaf extract alone increased SCE frequency at the 48-hour treatment period; however, it induced the CA and MN at all concentrations and at all treatment periods. Sf plus MMC (mitomycin C) synergically induced SCE and CA, except the highest concentration of Sf leaf extract and MMC on induction of SCE. In addition, Sf leaf extract induced the effect of MMC on MN frequency for 24 hours, but it significantly decreased the effect of MMC on MN frequency for the 48-hour treatment period. Sf leaf extract showed a cytotoxic effect by decreasing the MI; however, it did not decrease the PI and NDI. In the presence of S9 mix, Sf leaf extract did not increase the SCE, when compared to solvent control, whereas it reduced the effect of cyclophosphamide (Cyp). Sf leaf extract induced the CA and MN, but could not increase the effect of Cyp on CA and MN formation. Sf leaf extract had no cytotoxic effect; however, it induced the cytotoxicity of Cyp.

Sex-, tissue-, and exposure duration-dependent effects of imidacloprid modulated by piperonyl butoxide and menadione in rats. Part I: oxidative and neurotoxic potentials.

Earlier research has evidenced the oxidative and neurotoxic potential of imidacloprid, a neonicotinoid insecticide, in different animal species. The primary aim of this study was to determine how metabolic modulators piperonyl butoxide and menadione affect imidacloprid's adverse action in the liver and kidney of Sprague-Dawley rats of both sexes. The animals were exposed to imidacloprid alone (170 mg kg⁻¹) or in combination with piperonyl butoxide (100 mg kg⁻¹) or menadione (25 mg kg⁻¹) for 12 and 24 h. Their liver and kidney homogenates were analysed spectrophotometrically for glutathione peroxidase, glutathione S-transferase, catalase, total cholinesterase specific activities, total glutathione, total protein content, and lipid peroxidation levels. Imidacloprid displayed its prooxidative and neurotoxic effects predominantly in the kidney of male rats after 24 h of exposure. Our findings suggest that the observed differences in prooxidative and neurotoxic potential of imidacloprid could be related to differences in its metabolism between the sexes. Co-exposure (90-min pre-treatment) with piperonyl butoxide or menadione revealed tissue-specific effect of imidacloprid on total cholinesterase activity. Increased cholinesterase activity in the kidney could be an adaptive response to imidacloprid-induced oxidative stress. In the male rat liver, co-exposure with piperonyl butoxide or menadione exacerbated imidacloprid toxicity. In female rats, imidacloprid+menadione co-exposure caused prooxidative effects, while no such effects were observed with imidacloprid alone or menadione alone. In conclusion, sex-, tissue-, and duration-specific effects of imidacloprid are remarkable points in its toxicity.

In vitro evaluation of the protective effects of 4-thujanol against mitomycin-C and cyclophosphamide-induced genotoxic damage in human peripheral lymphocytes.

4-Thujanol (sabinene hydrate), a bicyclic monoterpene alcohol, is found in the essential oils of many aromatic and medicinal plants and is widely used as a fragrance and flavouring agent in many different products. The aim of this study was to evaluate the protective effects of 4-thujanol against the genotoxic effects induced by mitomycin C (MMC) and cyclophosphamide (CP) in human lymphocytes, using the chromosome aberrations, sister chromatid exchanges, and micronucleus tests, in the absence and in the presence of S9 mix, respectively. The cells were treated with 0.25 µg/mL MMC and 28 µg/mL CP as alone and cotreated with 13 + 0.25, 26 + 0.25, and 52 + 0.25 µg/mL 4-thujanol + MMC and with 13 + 28, 26 + 28, and 52 + 28 µg/mL 4-thujanol + CP as a mixture. The present study showed that 4-thujanol was unable to reduce the genetic damage induced by MMC, in the absence of S9 mix. On the other hand, probably the metabolites of 4-thujanol act as an antagonist and markedly antagonize CP-induced genotoxicity, in the presence of S9 mix. In general, 4-thujanol + MMC and 4-thujanol + CP decreased the mitotic index, proliferation index and nuclear division index to the same extent or more than those of individual exposure of MMC or CP. In conclusion, 4-thujanol significantly reduced (p < 0.001) the genotoxic damage induced by CP but not MMC when compared with the respective positive control alone. We can suggest that 4-thujanol may improve the chemopreventive effects and may also reduce the harmful side effects of CP, which is widely used in chemotherapy against cancer, without reducing its antiproliferative activities.