Micronuclei In Polychromatic Erythrocytes Research Articles

Cytotoxic, acute oral toxicity, genotoxic and mutagenic assessment of the essential oil from fresh leaves of Croton argyrophyllus (Kunth.)

Ethnopharmacological relevanceCroton argyrophyllus Kunth., commonly known as “marmeleiro” or “cassetinga,” is widely distributed in the Brazilian Northeast region. Its leaves and flowers are used in traditional medicine as tranquilizers to treat flu and headaches. Aim of the studyThis study was conducted to determine the chemical composition and toxicological safety of essential oil from C. argyrophyllus leaves using in vitro and in vivo models. Materials and methodsThe chemical composition of the essential oil was determined using a gas chromatograph coupled to a mass spectrometer. Cytotoxicity was tested in the HeLa, HT-29, and MCF-7 cell lines derived from human cells (Homo sapiens) and Vero cell lines derived from monkeys (Cercopithecus aethiops) using the MTT method. Acute toxicity, genotoxicity. Mutagenicity tests were performed in Swiss mice (Mus musculus), which were administered essential oil orally in a single dose of 2000 mg/kg by gavage. ResultsThe main components of the essential oil were p-mentha-2-en-1-ol, α-terpineol, β-caryophyllene, and β-elemene. The essential oil exhibited more than 90% cytotoxicity in all cell lines tested. No deaths or behavioral, hematological, or biochemical changes were observed in mice, revealing no acute toxicity. In genotoxic and mutagenic analyses, there was no increase in micronuclei in polychromatic erythrocytes or in the damage and index in the comet assay. ConclusionsThe essential oil was cytotoxic towards the tested cell lines but did not exert toxic effects or promote DNA damage when administered orally at a single dose of 2000 mg/kg in mice.

Evaluation of Genotoxic and Cytotoxic Effects of Gluten in Male Albino Mice

Gluten is a protein commonly found in daily diets in the form of wheat, barley, rye, and other grains. It serves as the structural component in flour, providing the binding qualities that maintain the shape and texture of food items. This study aimed to investigate the genotoxic and cytotoxic effects of gluten on bone marrow chromosomes and DNA of male albino mice. The animals were divided into four groups: a control group, a negative control group that received an oral dose of 0.02M glacial acetic acid, and two groups that were treated with gluten dissolved in 0.02M glacial acetic acid at doses of 1.5 g/kg and 3.0 g/kg body weight. The treated animals received oral doses with non-consecutively three times a week for a period of four weeks. The study evaluated chromosomal aberrations in the bone marrow, micronucleus test, and DNA damage using the comet assay. The results of the study showed that treatment with 1.5 and 3.0g/kg body weight of gluten induced chromosomal aberrations and damage in DNA content, with an increase in the severity of effects at a higher dose of gluten. The chromosomal aberrations seen included deletion, fragment, centromeric attenuation, centric fusion, ring formation, end to end association, chromosomal gap, beaded chromosomes, and polyploidy. The micronucleus test revealed toxicity in the bone marrow, as shown by appearance of micronuclei in polychromatic erythrocytes and a reduction in the ratio of polychromatic erythrocytes. The comet assay showed a significant increase of DNA damage in the tail length of the comet cells. This study concluded that the treatment with gluten has detrimental effects on the bone marrow chromosomes and DNA of mice, as demonstrated by the increased chromosomal aberrations, micronuclei, and DNA damage observed in the treated mice. So, the use of gluten should be within an acceptable and safe range.

Genotoxic and chemopreventive potentials of ethanol leaves extract of Annona muricata on N-Ethyl-N-Nitrosourea-induced pro-leukaemia carcinogen in mice model by bone marrow micronucleus assay

Background. Studies have proven the effect of several agents, including natural products, to induce, prevent and treat genotoxicity through experimental models and clinical trials. In this study, the genotoxic preventive potential of Annona muricata ethanol extract on N-Ethyl-N-Nitrosourea (ENU)-induced pro-leukaemia in mice models using micronuclei formation in bone marrow was assessed. Materials and methods. Forty-eight mice weighing 18-24g were randomly divided into six groups of eight mice. The mice were intravenously administered 20mg/kg of NEU 48 hourly 3 times, 80mg/kg of NEU 48 hourly 3 times. The negative control was fed with feed and water only. We introduced 0.2ml (0.1g/ml) ethanolic extract of Annona muricata for 3 weeks prior to NEU low dosage administration, 0.2ml (0.1g/ml) ethanolic extract of Annona muricata for 3 weeks prior to ENU high dosage and Annona muricata (ethanolic extract) administration, and gave commercial diet to the adverse/ toxicity group. The bone marrow was harvested, smeared and stained using MayGrumwald. The procedure enabled the determination of micronucleus polychromatic erythrocytes (MNPCEs) microscopically. Results. Groups exposed to various dosages of the ENU yielded significantly increased MNPCEs, with group B producing higher MNPCEs. The groups treated with the extract displayed a significant reduction in the MNPCEs despite prior exposure to concentrations of NEU. The adverse group displayed no difference in MNPCEs compared with the negative control. Conclusion. The ENU induced genotoxicity depending on its concentration. The extract displayed a profound capacity to prevent genotoxicity and alleviate leukaemia with good tolerance.

Comparative evaluation of the genotoxicity of carbendazim technical grade active ingredients in the Ames test and micronucleus in vivo test

Introduction. Carbendazim is a systemic benzimidazole fungicide used against a wide range of crop diseases. The ability of carbendazim to induce the incidence of chromosomal aberrations and micronuclei in mammalian cells by influencing the processes of mitotic spindle formation in the cell cycle have been shown in various in vitro and in vivo tests. Contradictory data were obtained in the bacterial test system Salmonella/microsomes, indicating both the absence and the presence of mutagenic activity of carbendazim. The discrepancy in the results may stem from the presence of impurities. The aim of the study was a comparative evaluation of the genotoxicity of various technical products of carbendazim. Materials and methods. The genotoxicity of carbendazim was studied using the plate incorporation version of the Ames test on 5 strains of Salmonella typhimurium in the presence and the absence of metabolic activation system (+S9/-S9) and in a micronucleus test in CD-1 mice. Two technical grade active ingredients (TGAI) and an analytical standard for carbendazim were tested. Results. In the Ames test, the analytical standard of carbendazim possessed no mutagenic activity (±S9) on any of the strains. The most pronounced mutagenic effect was observed for the TGAI I in TA98 strain, the number of revertants at the maximum concentration was 5-7 times higher than that in the negative control. The positive effects of carbendazim TGAIs in the Ames test are likely mediated by the presence of impurities. Under in vivo conditions, all tested TGAIs of carbendazim induced a statistically significant and dose-dependent formation of micronuclei in polychromatic erythrocytes (PCE) of mouse bone marrow. The mean frequency of PCE with micronuclei at the maximum dose exceeded this rate in the negative control by 21-24 times. Research limitations. The study is limited to testing the mutagenic activity of two samples of carbendazim technical products and one sample of its analytical standard in both in vivo and in vitro tests. Conclusion. Taking into account the high content of the active substance in the tested TGAIs, the bacterial reverse mutation test is a highly sensitive method for assessment of the equivalence of carbendazim generic products. The use of a micronucleus test for evaluating of the equivalence of carbendazim TGAIs to the original substance is inappropriate due to the pronounced aneugenic effect.

Evaluation of carcinogenic activities and sperm abnormalities of Gram-negative bacterial metabolites isolated from cancer patients after subcutaneous injection in albino rats.

Microbial pathogens drive tumorigenesis in 20% of cancer cases, so the present study is aimed to evaluate the carcinogenic activities, sperm abnormalities and other dangerous effects of the subcutaneous injection of extracts obtained from various clinical Gram-negative bacteria derived from cancer patients using albino rats. We isolated, identified and extracted of their secondary metabolites of carbapenem resistant Gram-negative bacteria derived from cancer patients. Various methods have been used to determine hepatotoxicity, nephrotoxicity, tumorigenesis, inflammatory and sperm abnormalities in the albino rats injected with extracts. In comparison with the normal animals group, all extracts induced hepatotoxicity which was evidenced by the significant elevation in the activity of the serum alanine aminotransferase, aspartate aminotransferase, gamma-glutamyltransferase and alkaline phosphatase; also, nephrotoxicity that was indicated through the marked increase in the serum urea and creatinine levels; tumorigenesis was achieved from the sharp elevation in serum levels of alpha fetoprotein, carcinoembryonic antigen and lactate dehydrogenase values as tumor markers; as well as severe inflammatory characteristics were monitored from the marked raise of tumor necrosis factor alpha and interleukin-1beta. Furthermore, the proportion of micronuclei in polychromatic erythrocytes and sperm abnormalities were statistically significant in all groups compared to control group. Various kinds of head abnormalities and coiled tail were noted. Histopathological examination of hepatic tissue came in line with the biochemical and cytological findings. It could conclude that the extracts of Serratia sp. Esraa 1, Stenotrophomonas sp. Esraa 2, Acinetobacter sp. Esraa 3, Escherichia sp. Esraa 4 and Pseudomonas sp. Esraa 5 were able to initiate cytotoxicity and tumorigenesis in rats.

Antimutagenic activity of nanoparticles of Rhaphidophora pinnata leaves in mice using micronucleus assay.

Cancer is one of the deadliest diseases in the world. Cancer may occur due to gene mutation. Rhaphidophora pinnata is a plant that has many benefits, especially in the leaves which have been used traditionally to treat cancer. The aim of this research is to test the antimutagenic activity of nanoparticles R. pinnata using the micronucleus method. The mice were induced with cyclophosphamide and then followed with the administration of nanoparticles of R. pinnata at the doses of 50, 100, 200 mg/kg for 7 days. The antimutagenic activity was evaluated at the decrease in the number of micronucleus in 200 polychromatic erythrocytes (PCE) cells of mice bone marrow. The result showed that the reduction of amount of micronucleus in PCE of a negative control group, treatment groups, and normal group is 22.65%, 60.3%, 79.6%, 93.8%, and 100%. These results indicate that the antimutagenic activity of nanoparticle of R. pinnata increases proportionally as the doses were increased. It can be concluded that nanoparticles R. pinnata at the doses of 50, 100, and 200 mg/kg have antimutagenic activity.

Depletion of NK Cells Resistant to Ionizing Radiation Increases Mutations in Mice After Whole-body Irradiation.

Ionizing radiation is a very powerful genetic mutagenic agent. Although immune cells are very sensitive to radiation, their sensitivity varies between different types of immune cell. We hypothesized that radiation-resistant immune cells survive after irradiation and then play a role in removing mutant cells. Splenic lymphocytes and mice were irradiated with γ-rays. Cell populations were analyzed using flow cytometry after dyeing with antibodies and expression of B-cell lymphoma 2 (BCL2) was measured by western blot analysis. To deplete natural killer (NK) cells, anti-asialo GM1 antiserum was used. Micronuclei in polychromatic erythrocytes were measured by May-Grunwald/Giemsa staining. H-2Kb loss variant in T-cells induced by irradiation of B6C3F1 mice were detected by flow cytometry. When splenic lymphocytes were irradiated in vitro, B cells notably died, while NK cells did not. In vivo, on the third day after whole-body irradiation, the total number of lymphocytes in the spleen decreased rapidly, but the proportion of NK cells was approximately three times higher than that of the normal control group. In addition, it was confirmed that high expression of BCL2 in NK cells was maintained after irradiation, whereas that of B-cells was not. Removal of NK cells by injection with anti-asialo GM1 antiserum immediately after irradiation increased the micronuclei of polychromatic erythrocytes in the bone marrow and the variant fraction with H-2kb loss in the spleen. These results provide important evidence that radioresistant NK cells apparently survive by escaping apoptosis in the early stages after irradiation, and work to eliminate mutant cells resulting from γ-ray irradiation. Future studies are needed to reveal why NK cells are resistant to radiation and the in-depth mechanisms involved in the elimination of radiation-induced mutant cells.

Radiation mitigating activities of Psidium guajava L. against whole-body X-ray-induced damages in albino Wistar rat model

In the present study, we investigated radiation mitigating activities of Psidium guajava L. (P. guajava) against whole-body X- ray induced damages in albino Wistar rat model. The animals were orally administered with 200 mg/kg bodyweight of hydroalcoholic leaf extract of P. guajava for five consecutive days and on the fifth day, after the last dose of extract administration, animals were exposed to 4 Gy of X-rays. Rats were sacrificed 24 h post X–ray irradiation. The radiomitigating activity of the herb extract was assessed by micronucleus assay, histopathology of the small intestine and hematological parameters. Hepatic cyclooxygenase–2 (COX-2), interleukin–6 (IL-6) and interleukin –10 (IL-10) levels were assayed to validate the anti-inflammatory property. Biochemical estimations were also performed in RBC lysates to corroborate antioxidant properties in the leaf extract. HPLC analysis of crude extract confirmed the presence of standard flavonoid quercetin. Our results indicated that radiation elevated COX-2, IL-6 and decreased IL-10 levels and also induced micronucleus formation in polychromatic erythrocytes, simultaneously impairing hematological parameters along with erythrocyte antioxidants. The animals pre-treated with P. guajava exhibited a significant decrease in the COX-2 (P ≤ 0.01), IL-6 levels (P ≤ 0.05) and also displayed significant increase in the hepatic IL-10 levels (P ≤ 0.01). Pre-treatment with plant extract improved antioxidant enzyme activities, hematological parameters and reduced the intestinal damage by recovering the architecture of the small intestine. Moreover, extract also rendered protection against radiation induced DNA damage, as evidenced by the significant (P ≤ 0.01) decrease in the percentage of radiation-induced micronucleus in polychromatic erythrocytes. Furthermore, the herb extract treatment increased radiation LD50/30 from 6.6 Gy to 9.0 Gy, offering a dose reduction factor (DRF) of 1.36. Our findings for the first time propose the beneficial use of P. guajava as a radioprotector against X-ray induced damage.

Next tier in vitro and in vivo nonclinical studies further elucidating the safety and toxicity profile of MB-102, a novel fluorescent tracer agent for measurement of glomerular filtration rate

MB-102 was designed for measurement of real-time glomerular filtration rate (GFR). Previously reported in vitro and in vivo nonclinical studies clearly demonstrated negligible toxicity, resulting in FDA clearance for First-in Human, proof of concept clinical studies. The next tier of safety and toxicity studies are reported herein.MB-102 did not demonstrate any phototoxic potential in a BALB/c 3T3 mouse fibroblast study. Co-administration of MB-102 and iohexol resulted in pharmacokinetic parameters virtually identical to the values observed upon individual administration in beagle dogs. A single dose of MB-102 administered either intravenously (18.6 mg/mL) or perivenously (0.25 mL) was well-tolerated in NZ white rabbits, with no adverse inflammation or irritation. MB-102 did not induce micronuclei in polychromatic erythrocytes for rat bone marrow cells treated up to 450 mg/kg/day, the maximum feasible dose. Two separate optical imaging studies demonstrated that MB-102 distributes rapidly and thoroughly throughout the test subjects, followed by rapid clearance from the body without any preferential localization in any particular tissue or organ, with the exception of the bladder, which is totally consistent with a known GFR agent. In addition, two-week repeat intravenous (once-daily) toxicity and toxicokinetic studies were conducted in rats and beagles, with no MB-102- related effects.Thus, for the studies reported herein, there were no toxicological effects of concern for MB-102.

Genotoxic evaluation of sibipiruna extract (Caesalpinia peltophoroides Benth) in vivo

Caesalpinia peltophoroides Benth, popularly known as sibipiruna or false brazilwood, is an ornamental species with wood potential and with great distribution in Brazil. The genus Caesalpinia has more than five hundred species, most of which have not yet been studied for their pharmacological potential. Several species of the genus are known for their antioxidant and anti-inflammatory activities. The aim of the present study was to evaluate the effect of sibipiruna leaf and flower extract on Cyclophosphamide (CP) induced DNA damage in male Swiss mice using the micronucleus test. The animals (6 animals/group) were treated for 15 consecutive days with ethanolic extract (via gavage) and on day 15 received intraperitoneally NaCl (0.9%) or CP (25 mg/Kg), being sacrificed 24 hours after treatment to evaluate the frequency of micronucleated polychromatic erythrocytes (MNPCEs). The results showed that pretreatment with the ethanolic flower extract and sibipiruna leaf, under the conditions tested, did not reduce the frequency of MNPCEs induced by CP when compared to the positive control group. However, the groups treated only with the ethanolic extract of sibipiruna flowers and leaves significantly increased the frequency of micronuclei in polychromatic erythrocytes of bone marrow when compared to the negative control group, thus demonstrating a possible mutagenic effect. Therefore, it was possible to verify that sibipiruna did not present antimutagenic activity, but a plant with possible mutagenic action in the concentrations used.

Genotoxic and immunotoxic effects of the organophosphate metabolite diethyldithiophosphate (DEDTP) in Vivo

Diethyldithiophosphate (DEDTP) is a metabolite produced by the degradation of organophosphorus pesticides and a dialkylphosphate that is chemically synthesized with widespread commercial use. DEDTP is a stable compound, and most studies considered it harmless. However, some studies found adverse effects in vitro, including toxicity in different human cell types. However, there are no in vivo studies characterizing the toxicological effects of DEDTP. Therefore, we investigated the genotoxicity and immunotoxicity of DEDTP in a murine model. We used C57BL/6J and Balb/c mice (6–8-weeks-old) exposed to DEDTP i.p. We established that the medium lethal dose (LD50) of DEDTP was 0.537 g/kg. DEDTP was genotoxic in vivo because it increased the frequency of micronuclei in polychromatic erythrocytes in peripheral blood at 0.05 g/kg. DEDTP showed immunotoxic effects on T and Natural Killer cells and immunomodulatory effects on macrophages, especially M2 type that increased 1000% after 20 days of exposure to 0.01 g/kg. These effects modified the response to a tumoural challenge. DEDTP exposure increased tumour size and reduced the response of lymphocytes to tumoural antigen stimulation. We conclude that exposure to DEDTP produced genotoxic and immunomodulatory effects at environmentally relevant concentrations, which affected the growth of tumours in vivo. These results suggest that DEDTP might reduce the quality of life in exposed individuals, and it exhibits genotoxicity and immunotoxicity despite its stability.

Protective effect of exogenous melatonin in rats and their offspring on the genotoxic response induced by the chronic consumption of alcohol during pregnancy

Maternal alcoholism can induce serious injuries in embryonic and fetal development. The metabolism of alcohol increases the production of free radicals and acetaldehyde, molecules capable of reacting with DNA, impairing organogenesis. Melatonin is a powerful antioxidant that can act as a protective agent against DNA damage caused by genotoxic agents, such as ethanol. This study evaluated the protective effect of exogenous melatonin in rats and their offspring on the genotoxic response induced by chronic alcohol consumption during pregnancy. Twenty-five pregnant rats were divided into the following groups: NC - Negative control; ET - Rats receiving ethanol (3 g/kg/day); ET+10 M - Rats receiving ethanol (3 g/kg/day) and melatonin (10 mg/kg/day); ET+15 M - Rats receiving ethanol (3 g/kg/day) and melatonin (15 mg/kg/day); PC - Positive control (40 mg/kg cyclophosphamide). The dams and 10 pups (five males and five females) from each group were anesthetized to collect blood and liver from the dams and blood, liver and brain of neonates to evaluate the frequency of DNA damage by the comet assay. Blood was also used for the micronucleus test. The results demonstrated a significant increase in DNA damage in the blood and liver cells of dams receiving ethanol and their offspring as well as in the brain of these neonates. Treatments with melatonin (10 and 15 mg/kg/day) significantly reduced the genotoxicity caused by ethanol in the blood of dams and neonates (males and females), liver of dams and male offsprings, and in the brain of female offsprings. It was shown that only the female offspring exposed to maternal alcohol consumption showed a higher frequency of micronuclei in polychromatic erythrocytes. Consequently, exogenous melatonin may be a promising therapeutic agent against genotoxic damage induced by alcohol; however, further studies are needed to confirm these benefits.

Potassium bromate – inhalable fraction. Documentation of proposed values of occupational exposure limits (OELs)

Potassium bromate (V), (KBrO3) exists as white crystals, crystalline powder or granules. It is highly soluble in water, tasteless and odourless. Potassium bromate is a strong oxidizing agent. In the past it has been used as food additive in flour milling, as an ingredient in fish-paste in Japan, in cheese making, in beer malting, as a component of cold hair wave liquid and an oxidizing compound. Moreover, bromate is formed as a by-product of water disinfection by ozonation and is frequently detected in tap and bottled water. In fact bromate is one of the most prevalent disinfection by-product of surface water. Occupational exposure to potassium bromate occurs mainly in production plants during packaging processes. In Poland, about 1 160 persons were exposed to this compound in 2016. Bromate caused many acute poisonings by accidental ingestion, mainly among children, and more often ingested for tentative suicide by young women, especially hairdressers. In the acute phase of poisoning, gastrointestinal disturbances, irreversible hearing loss, and acute renal failure were observed. Acute renal failure was associated with hemolytic uremic syndrome. There are no data on chronic intoxication of humans by potassium bromate and epidemiological studies on this subject. On the basis of the value of median lethal dose (LD50) per os in rat, potassium bromate has been classified as a compound belonging to the category „Toxic”. Major toxic signs and symptoms in animals after a single intragastric administration of potassium bromate were tachypnea, hypothermia, diarrhea, lacrimation, suppression of locomotor movement, ataxic gait, and animals lying in a prone position. At autopsy the major findings were strong hyperemia of glandular stomach mucosa and congestion of lungs. Microscopically, necrosis and degenerative changes of the proximal tubular epithelium and hearing cells of internal ear were found. It was stated that the compound is not irritating, corrosive or sensitizing. In subchronic and chronic exposure of rodents, potassium bromate led to liver and kidney dysfunction and tubular epithelial damage. Potassium bromate had mutagenic and clastogenic effects. It induced point mutations, structural chromosome aberrations, micronuclei in polychromatic erythrocytes in male mice, DNA oxidative damage by modification of deoxyguanosine to 8-hydroxydeoxyguanosine, and DNA double-strand breakage. Potassium bromate induced neoplasms in rodents and exerted promotion effect in comparison with well-known carcinogens. Besides from preneoplastic changes, expressed by high incidences of renal cell tumors and dysplastic foci, bromate induced solid neoplasms, such as adenomas and adenocarcinomas in a rat kidney and thyroid, and mesotheliomas of peritoneum and tunica vaginalis testis. The European Union classified potassium bromate as a substance that can cause cancer (Group 1.B), whereas IARC classified it as a presumably carcinogenic agent for human (Group 2.B). In principle, effects of bromate on reproduction and ontogenetic development of offspring were not observed. Animal studies suggest that a kidney is a critical organ in the exposure to potassium bromate. The results of subchronic exposure of male rats to potassium bromate administered with drinking water were used to calculate the value of MAC-NDS. The critical effects in kidney were: an increase of organ weight and dose-dependent histopathological alterations defined as epithelium urinary tract hypertrophy. The NOAEL value is 1.5 mg/kg b.w./day. For the calculation of the maximum allowable concentration (MAC) value, 5 uncertainty factors with total value of 24 were used. Based on this estimation it is proposed to accept the MAC-TWA value for potassium bromate at 0.44 mg/m3. The risks of kidney and thyroid cancer in condition of occupational exposure are 2.2 · 10-3 and 0.6 · 10-3, respectively. There is no reason to determine the value of short-term exposure limit (STEL) and the biological exposure index (BEI). „Carc.1.B” notation (carcinogenic substance) was proposed

Genotoxicity assessment of the novel antitussive agent Benzonatate and its major metabolite

Benzonatate (TESSALON®) is a peripherally acting oral antitussive. It undergoes rapid ester hydrolysis producing 4-(butylamino) benzoic acid (BBA) and methylated polyethylene glycol (MPG) metabolites, which are eliminated in urine and feces. The nonclinical and clinical efficacy of Benzonatate has been demonstrated over the last 60 years, but its safety was not fully assessed. In this study, we tested the genotoxicity of Benzonatate and its major metabolite BBA in an in vitro bacterial reverse mutation and in vivo micronucleus assays. A chromosomal aberration assay was also performed on Benzonatate and BBA. In the reverse mutation assay, Benzonatate and BBA doses 1.5–5000 μg/plate ± S9 metabolic activation were used and the numbers of revertants/plate were compared to various controls. Chromosomal aberration assays with human peripheral blood lymphocytes used Benzonatate and BBA concentrations 25–2000 and 62.5–1930 μg/mL, respectively. A CByB6F1 mouse bone marrow micronucleus assay was performed as part of a 28-day oral toxicology study at up to 250 mg/kg/day. The frequencies of micronuclei in polychromatic erythrocytes in treated groups were compared with the control group. Neither Benzonatate nor BBA induced significant mutagenicity in any of the bacterial strains, with or without metabolic activation. They also did not produce any biologically relevant structural or numerical aberrations in human chromosomes. Benzonatate and its BBA and MPG metabolites rapidly produced from esterase activity did not produce any significant increase in the incidence of micronucleated polychromatic erythrocytes. In conclusion, Benzonatate and its major metabolite BBA were not mutagenic and did not cause numerical or structural chromosome alterations. While the MPG metabolite was not tested, studies on structural analogues indicated it was also unlikely to be genotoxic. This was supported by oral rodent carcinogenicity assays showing no increase in malignancies.

Protective Efficacy of Asparagus racemosus root extract and Isoprinosine against Ionizing Radiation - induced Clastogenicity and Toxicity in Swiss Albino Mice

: Objective: We aimed to evaluate anticlastogenic and radioprotective potential of Asparagus racemosus root extract (ARE) and Isoprinosine (IPR) against electron beam radiation (EBR) induced clastogenicity and toxicity in Swiss albino mice. Methodology: In the pre-radiation study, the experimental animals were orally administered ARE – 200mg and IPR – 400mg/ kg b.wt once daily for 15 consecutive days. The animals exposed to sublethal dose (6Gy) of whole body EBR. Chromosomal aberration analysis and micronucleus assay were carried out in the bone marrow cells of the experimental animals. The various types of aberrations were scored and the micronuclei in Polychromatic Erythrocytes (PCE) and Nomochromatic Erythrocytes (NCE) were recorded. Assessment of Granulocyte Macrophage Colony Stimulating Factor (GM-CSF), was performed using mouse GM-CSF Picokine ELISA kit. Non-specific Alpha – esterase activity was determined by simultaneous azo dye coupling method. Dose Reduction Factor (DRF) was calculated to determine the protective role of ARE and IPR against EBR. Result: Treatment of mice with ARE-200 mg/kg b.wt and IPR-400mg/kg b.wt decreased the percentage of the total aberration compared to the irradiated group; significantly reduced (P<0.05) the frequency of Mn PCE and Mn NCE when compared with irradiation alone groups. Irradiation reduced the level of GM-CSF in the splenocytes which was enhanced by the pre-treatment with ARE and IPR. There was a significant increase in the number of alpha-esterase positive cells in the pre-treatment group compared to radiation control. Increase in survival percentage was observed in the pre-treated mice when compared to radiation alone group. The DRF value of 1.11 and 1.04 was observed respectively. Conclusion: The present study suggests that the antioxidant potential of ARE and IPR could be of extreme significance in offering radioprotection and may be useful in combating various free-radical and reactive oxygen species – mediated human pathological conditions.Key words: Asparagus racemosus root extract, Isoprinosine, Electron beam radiation, Clastogenicity, Toxicity.

MANGIFERIN PROTECTS RENAL IMPAIRMENT AGAINST BENZO(A)PYRENE INDUCED TOXICITY BY REGULATING MITOCHONDRIAL AND DNA INTEGRITY

Contaminated food and water ingestion and inhalation of polycyclic aromatic hydrocarbon are the main sources of human exposure to benzo(a)pyrene leading to cause renal injury and provoking a nephropathic response. Mangiferin is a highly potent antioxidant present in mango and known for several medicinal properties. The present study was undertaken to evaluate the renoprotective effect of mangiferin against benzo(a)pyrene induced toxicity. Benzo(a)pyrene was administered at a dose of 120.0 mg/kg once alone or in combination with mangiferin at 10.0 and 20.0 mg/kg for seven days in Swiss albino mice. Exposure to benzo(a)pyrene decreased the activities of glutathione peroxidase and increased glutathione-S-transferase level in the kidneys of mice. Moreover, DNA alkaline unwinding assay exhibit a significant decrease in F-value for the toxic control group in comparison to the normal mice, which is a marker for alteration in DNA integrity. Benzo(a)pyrene treatment also revealed an increased number of micronuclei in polychromatic erythrocytes in comparison with the control group indicating chromosomal damage in erythrocytes of bone marrow. Mangiferin pretreatment significantly improved the renal mitochondrial antioxidant status and restored the renal DNA integrity, thus demonstrating the protective effect in benzo(a)pyrene-treated mice. Dietary inclusion of mangiferin could exert protective effects against renal toxicity resulting from benzo(a)pyrene exposure.Keywords: Benzo(a)pyrene, GPx, GST, Mangiferin, Micronucleus Â

Evaluation of antigenotoxic activity of ethanolic extract of Calotropis procera root in 7,12-dimethylbenz[a]anthracene induced genotoxicity in Wistar rats

Background: Chemopreventive compounds may play an important role in cancer prevention. However, many chemopreventive agents available currently are associated with toxicity. Hence, there is a need to screen for newer compounds with chemopreventive potential. Many medicinal plants can be developed as prospective chemopreventive candidates. Aims and Objectives: The aim of the study was to assess the protective effect of ethanolic extract of calotropis procera root in 7,12-dimethylbenz[a]anthracene (DMBA) induced genotoxicity in Wistar rats by micronucleus assay. Materials and Methods: Wistar rats were divided into 4 groups randomly. Group 1 received distilled water (control group). Group 2 was administered DMBA (30 mg/kg body weight [BW], single dose) intraperitoneally on the 5th day of the experiment. Group 3 rats were pretreated with C. procera root extract (500 mg/kg BW) orally for 5 days followed by DMBA injection intraperitoneally 2 h after C. procera root extract on the 5th day. Group 4 rats were given C. procera root alone orally for 5 days. The animals were sacrificed on the 6th day, and bone marrow was harvested for the micronucleus test. The percentage of micronuclei in polychromatic erythrocytes (%MnPCE) and PCE: NCE were determined. Results: Group 2 rats exhibited significant (P < 0.0001) increase in the %MnPCEs compared to control group. Group 3 and 4 rats did not show a significant increase in %MnPCEs compared to control group. The PCE: NCE ratio is decreased in Group 2 rats compared to the control group, but it is not statistically significant. The PCE: NCE ratio does not differ significantly from the control group in Groups 3 and 4. Conclusion: The ethanolic extract of C. procera root exhibits antigenotoxic activity in DMBA induced genotoxicity in Wistar rats.

Fitting Binomial, Quasi – Binomial, Poisson and Quasi - Poisson Models in Analyzing In Vivo Micronucleus Assay Data

Micronucleus assay is an important analysis for testing the genotoxicity of a compound thus, a careful analysis should be done. The main focus of this study was to perform the recommendations of Hothorn and Gerhard (2009) on analyzing the number and proportion of micronucleus polychromatic erythrocytes for a given number of polychromatic erythrocytes. The compound TO1 was evaluated using the Binomial, Poisson, quasi-Binomial and quasi-Poisson models. Results showed that most doses of TO1 had no significant effect on the proportion of micronucleus. The result of quasi- Binomial and quasi-Poisson model revealed that most of the inferences agree with the results of the traditional models. However, some inferences can lead to a false positive decision if over-dispersion was not taken into account. The analysis also showed that TO1 was found to be a negative compound.

Radioprotective effects of cimetidine on rats irradiated by long-term, low-dose-rate neutrons and 60Co \u03b3-rays

BackgroundCimetidine, an antagonist of histamine type II receptors, has shown protective effects against γ-rays or neutrons. However, there have been no reports on the effects of cimetidine against neutrons combined with γ-rays. This study was carried out to evaluate the protective effects of cimetidine on rats exposed to long-term, low-dose-rate neutron and γ-ray combined irradiation (n-γ LDR).MethodsFifty male Sprague-Dawley (SD) rats were randomly divided into 5 groups: the normal control group, radiation model group, 20 mg/(kg · d) cimetidine group, 80 mg/(kg · d) cimetidine group and 160 mg/(kg · d) cimetidine group (10 rats per group). Except for the normal control group, 40 rats were simultaneously exposed to fission neutrons (252Cf, 0.085 mGy/h) for 22 h every day and γ-rays (60Co, 0.097 Gy/h) for 1.03 h once every three days, and the cimetidine groups were administered intragastrically with cimetidine at doses of 20, 80 and 160 mg/kg each day. Peripheral blood WBC of the rats was counted the day following exposure to γ-rays. The rats were anesthetized and sacrificed on the day following exposure to 252Cf for 28 days. The spleen, thymus, testicle, liver and intestinal tract indexes were evaluated. The DNA content of bone marrow cells and concanavalin A (ConA)-induced lymphocyte proliferation were measured. The frequency of micronuclei in polychromatic erythrocytes (fMNPCEs), superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione peroxidase (GSH-Px) in the serum and liver tissues were detected.ResultsThe peripheral blood WBC in the cimetidine groups was increased significantly on the 8th day and the 26th day compared with those in the radiation model group. The spleen, thymus and testicle indexes of the cimetidine groups were higher than those of the radiation model group. The DNA content of bone marrow cells and lymphocyte proliferation in the cimetidine groups were increased significantly, and fMNPCE was reduced 1.41-1.77 fold in cimetidine treated groups. The activities of SOD and GSH-Px in the cimetidine groups were increased significantly, and the content of MDA in the cimetidine groups was decreased significantly.ConclusionsThe results suggested that cimetidine alleviated damage induced by long-term, low-dose-rate neutron and γ combined irradiation via antioxidation and immunomodulation. Cimetidine might be useful as a potent radioprotector for radiotherapy patients as well as for occupational exposure workers.

Radioprotective effect of Zamzam (alkaline) water: A cytogenetic study

BackgroundRadioprotectors are useful compounds to reduce radiation toxicity of normal cells. Many natural radioprotectors have antioxidant power and display fewer toxicity and side effects than the chemical ones. Alkaline waters such as Zamzam have antioxidant power potentially. This study aimed to investigate the radioprotective effect of Zamzam water in mice bone marrow exposed to gamma radiation by micronuclei test. MethodFive study groups including control group which was fed by ordinary water, the second group was fed by Zamzam water, and radiation groups were received 2Gy gamma with ordinary and Zamzam water for 10 days and another for 20 days. The frequency of micronuclei and polychromatic erythrocytes to normochromatic erythrocytes ratio were calculated by micronuclei test. ResultIn the absence of radiation, no significant difference was found between Zamzam group and control in the number of micronuclei in normochromatic erythrocytes, micronuclei in polychromatic erythrocytes, and the polychromatic erythrocyte to polychromatic erythrocyte plus normochromatic erythrocyte ratio. But all of these indices were significantly different between irradiated and non-irradiated groups. The frequency of micronuclei in polychromatic erythrocytes was not significantly different between 10 and 20 days Zamzam irradiated groups, but the reduction in micronuclei in normochromatic erythrocytes and an increase in the polychromatic erythrocyte to polychromatic erythrocyte plus normochromatic erythrocyte ratio compared to ordinary water were seen in 20 days Zamzam group. Dose reduction factor was 1.36 and 2 for Zamzam water groups of 10 days and 20 days, respectively. ConclusionThe results demonstrated that Zamzam alkaline water could reduce clastogenic and cytotoxic effects of gamma irradiation.