Micronucleated Normochromatic Erythrocytes Research Articles

The protective role of Ageratum conyzoides (Billy goat weed) in cyclophosphamide induced haematological damage and cytogenotoxicity

Medical plants are now explored as alternative for treatment and prevention of various disease conditions. Ageratum conyzoides (A. conyzoides) is a common plant with long traditional medicinal use history. This study investigated the hypothesis that A. conyzoides protects against haematological damage and cytogenotoxicity induced by acute exposure to cyclophosphamide. A total of twenty (24) adult male Wistar rats weighing 208.50±28.3 g was randomly divided into four groups of six animals each. Group 1 served as control group and received 0.5 ml of Tween-20 orally and sterile injection water intraperitoneally on days 1 and 4. Group 2 received 0.5ml of Tween-20 orally and 40 mg/kg body weight of cyclophosphamide intraperitoneally on days 1 and 4. Group 3 received 500 mg/kg body weight of A. conyzoides extract orally and sterile injection water intraperitoneally on days 1 and 4. Group 4 received 500 mg/kg body weight of A. conyzoides extract orally and 40 mg/kg body weight of cyclophosphamide intraperitoneally on days 1 and 4. Oral treatment was daily and lasted for 7 days. Whole blood was collected for complete blood count and assessment of Neutrophil-to-Lymphocyte ratio, Monocytes-to-Lymphocytes ratio (MLR) and Platelet-to-Lymphocyte Ratio (PLR) as biomarkers of systemic inflammation and immunosuppression; and bone marrow smear were analyzed for micronucleated normochromated and polychromated erythrocytes (MNNCE and MNPCE), and PCE/NCE ratio was scored as index of cytotoxicity following exposure to cycophosphamide and the protective role of A. conyzoides. Our results showed cyclophosphamide caused significant reduction in WBC, platelet, RBC, Hb and PCV values. Also, cyclophosphamide induced significant increased abnormal RBC morphophenotypes, including irregular, teardrop, macrocytes, helmet, fragmented, sickle, burr and target cells, with consequent increase in frequencies of micronucleated polychromatic and micronucleated normochromatic erythrocytes. Interestingly, treatment with A. conyzoides produced a significant amelioration of these cyclophosphamide-mediated effects. The mechanisms by which A. conyzoides ameliorated these toxic effects of cyclophosphamide remain to be fully investigated.

The protective effect of herniarin on genotoxicity and apoptosis induced by cisplatin in bone marrow cells of rats

Herniarin is a member of simple coumarins, which are a group of common secondary metabolites in plants. The aim of the present study was to investigate the effects of herniarin on genotoxicity and apoptosis induced by cisplatin in rat bone marrow cells. The experimental rats were treated with four different doses of herniarin (50, 100, 200, and 400 mg/kg.) for seven consecutive days. The cisplatin (5 mg/kg, i.p.) was injected into mice 1 h after the last oral herniarin administration on the seventh day. The protective effects of herniarin were investigated by hematological test, flow cytometry, micronucleus assay, and reactive oxygen species (ROS) level analysis. Herniarin caused a marked reduction in the frequencies of micronucleated polychromatic erythrocytes (MnPCEs) and micronucleated normochromatic erythrocytes (MnNCEs) 24 h after exposure to cisplatin at doses of 200 and 400 mg/kg. Furthermore, herniarin significantly increased the levels of both red and white blood cells in peripheral blood. Treatment of rats with herniarin before cisplatin, significantly decreased the percentage of apoptotic and necrotic cells and the ROS level in bone marrow cells. This study indicated that herniarin can be introduced as a new chemoprotective agent against cisplatin-induced genotoxicity in the future.

Protection from ionizing radiation-induced genotoxicity and apoptosis in rat bone marrow cells by HESA-A: a new herbal-marine compound.

HESA-A is an herbal-marine compound which improves the quality of life of end-stage cancer patients. The aim of the present study was to evaluate the possible protective effect of HESA-A against IR-induced genotoxicity and apoptosis in rat bone marrow. Rats were given HESA-A orally at doses of 150 and 300mg/kg body weight for seven consecutive days. On the seventh day, therats were irradiated with 4Gy X-rays at 1h after the last oral administration. The micronucleus assay, reactive oxygen species (ROS) level analysis, hematological analysis and flow cytometry were used to assess radiation antagonistic potential of HESA-A. Administration of 150 and 300mg/kg of HESA-A to irradiated rats significantly reduced the frequencies of micronucleated polychromatic erythrocytes (MnPCEs) and micronucleated normochromatic erythrocytes (MnNCEs), and also increased PCE/(PCE + NCE) ratio in bone marrow cells. Moreover, pretreatment of irradiated rats with HESA-A (150 and 300mg/kg) significantly decreased ROS level and apoptosis in bone marrow cells, and also increased white blood cells count in peripheral blood. For the first time in this study, it was observedthat HESA-A can have protective effects against radiation-induced genotoxicity and apoptosis in bone marrow cells. Therefore, HESA-A can be considered as a candidate for future studies to reduce the side effects induced by radiotherapy in cancer patients.

Metformin attenuates cisplatin-induced genotoxicity and apoptosis in rat bone marrow cells

Metformin is widely used as an oral hypoglycemic drug in the management of type 2 diabetes mellitus. This study evaluated the possible protective effects of metformin against cisplatin-induced genotoxicity and apoptosis in rat bone marrow cells. Two different doses of metformin (50 and 100 mg/kg b.w.) were administered orally to experimental animals for seven consecutive days. On the seventh day, the rats were exposed to cisplatin (5 mg/kg, i.p.) 1 h after the last oral metformin administration. Rats in the control group were treated orally with 10 ml/kg PBS for 7 consecutive days and a single intraperitoneal injection of saline (0.9%) on the 7th day. The antagonistic effects of metformin against cisplatin were evaluated using micronucleus assay, reactive oxygen species (ROS) level analysis, hematological analysis, and flow cytometry. Treatment with 50 and 100 mg/kg metformin before cisplatin injection produced a significant reduction in the frequencies of micronucleated polychromatic erythrocytes (MnPCEs) and micronucleated normochromatic erythrocytes (MnNCEs) 24 h after cisplatin treatment with a corresponding increase in the PCE/(PCE + NCE) ratio. Moreover, metformin markedly elevated the levels of both red and white blood cells in peripheral blood and decreased the percentage of apoptotic cells and the ROS level in bone marrow cells of rats treated with cisplatin. The data suggest that metformin has potential chemoprotective properties in rat bone marrow after cisplatin treatment, which support its candidature as a potential chemoprotective agent for cancer patients undergoing chemotherapy.

Protection Against Radiation-Induced Micronuclei in Rat Bone Marrow Erythrocytes by Curcumin and Selenium L-Methionine.

The search for potent radioprotective agents for the amelioration of radiation side effect is an important aim in radiobiology. The present study aimed to evaluate the effects of curcumin and seleno-L-methionine against radiation-induced micronucleus formation in rat bone marrow. In total, 40 male rats were divided into 8 groups (n=5 each), including control, curcumin or seleno-L-methionine treated alone or in combination, 2 Gy irradiation, irradiation of treated groups with curcumin or seleno-L-methionine or their combination. Curcumin was administrated orally and seleno-L-methionine was injected intraperitoneally 24 hours before irradiation. The frequency of micronucleated normochromatic erythrocytes (MnNCEs) and micronucleated polychromatic erythrocytes (MnPCEs) was scored in 5,000 polychromatic erythrocytes (PCEs) and the cell proliferation ratio [(PCE/(PCE+NCE); NCE=normochromatic erythrocytes] was calculated for each treatment group. Data were analyzed by the SPSS software version 16.0 and P<0.05 was considered as statistically significant differences. Pretreatment with curcumin and seleno-L-methionine before irradiation reduced the frequency of MnPCEs and MnNCEs (P=0.01) and increased the cell proliferation ratio. Moreover, the results showed that this pretreatment reduced the frequency of MnPCEs with a protection factor (PF) of 1.2 and 1.6, respectively. The combination of curcumin and seleno-L-methionine in reducing MnPCEs and MnNCEs was not more effective than each agent alone, while improved cell proliferation ratio. Both curcumin and seleno-L-methionine showed potent protection against radiation induced MN in bone marrow cells. The combination of the two agents further ameliorates this activity, thus leading to improve bone marrow protection.

Evaluation of Duloxetine as Micronuclei Inducer in an Acute and a Subchronic Assay in Mouse.

Duloxetine is a widely used antidepressant worldwide. In the present report, we evaluated its capacity to induce micronucleated polychromatic erythrocytes (MNPEs) and micronucleated normochromatic erythrocytes (MNNEs) in mice. Two assays were performed, one with a single chemical administration and the other with daily chemical administration. In the first, we administered the antidepressant once to groups of 5 mice by the intragastric (i.g.) route (2, 20, and 200 mg/kg) and performed the analysis at 24, 48, and 72 h postadministration. A control group administered i.g. distilled water was included in the assay, as well as another treated with the micronuclei-inducing chemical daunorubicin (2.5 mg/kg, injected intraperitoneally (i.p.)). In this assay, we found significant damage induced by duloxetine starting from the first time evaluated, showing the highest MNPE increase at the end of the assay. We observed a saturation effect as well, suggested by a decreasing relative efficiency with respect to each tested dose. In a second assay, we administered the antidepressant i.g. every day for 5 weeks (2, 6, and 12 mg/kg), and micronuclei analysis was performed at the end of each week. In this study, we also found a significant increase in both MNPEs and MNNEs which was clear by the second week of administration. Our results suggest that short-term as well as cumulative damage is produced by duloxetine. Thus, confirmation of the observed genotoxic potential in other models seems advisable, as well as caution when prescribing this antidepressant.

Radioprotective effects of Dragon's blood and its extract against gamma irradiation in mouse bone marrow cells

PurposeThe radioprotective effects of Dragon's blood (DB) and its extracts (DBE) were investigated using the chromosomal aberrant test, micronucleus and oxidative stress assay for anti-clastogenic and anti-oxidative activity. Materials and methodsAdult BALB/C mice were exposed to the whole body irradiation with 4 Gy 60Co γ-rays. DB and DBE were administered orally once a day from 5 days prior to irradiation treatment to 1 day after irradiation. The mice were sacrificed on 24 h after irradiation. The cells of bone marrow were measured by counting different types of chromosomal aberrations and the frequency of micronuclei. Oxidative stress response was carried out by analysis of serum from blood. ResultsDB and DBE significantly decreased the number of bone marrow cells with chromosome aberrations after irradiation with respect to irradiated alone group. The administration of DB and DBE also significantly reduced the frequencies of micronucleated polychromatic erythrocytes (MPCE) and micronucleated normochromatic erythrocytes (MNCE). In addition, DB and DBE markedly increased the activity of antioxidant enzymes and the level of antioxidant molecular. Malondialdehyde (MDA) and nitric oxide (NO) levels in serum were significantly reduced by DB and DBE treatment. ConclusionsOur data suggested that DB and DBE have potential radioprotective properties in mouse bone marrow after 60Co γ-ray exposure, which support their candidature as a potential radioprotective agent.

Amelioration of Cadmium-Produced Teratogenicity and Genotoxicity in Mice GivenArthrospira maxima(Spirulina) Treatment

Evaluation of the effects of Arthrospira maxima (AM) was made, otherwise known as Spirulina, on the teratogenicity, genotoxicity, and DNA oxidation processes induced by cadmium (Cd). Pregnant ICR mice were divided into groups and administered water, Cd only, AM only, or AM plus Cd. AM was administered orally at doses of 200, 400, and 800 mg/kg from gestational day 0 (GD0) to GD17, and at GD7 there was an intraperitoneal challenge of Cd (1.5 mg/kg). Cd only caused fetal malformations, including exencephaly, micrognathia, ablephary, microphthalmia, and clubfoot, as well as a significant increase in the quantity of micronucleated polychromatic erythrocytes (MNPE) and of micronucleated normochromatic erythrocytes (MNNE) in blood cells of both the mothers and their fetuses. An increased level of oxidation was also found, measured by a rise in the levels of the adduct 8-hydroxy-2-deoxyguanosine. In a dose-dependent manner, AM significantly reduced the number of external, visceral, and skeletal malformations, the quantity of MNPE and MNNE, and the level of DNA oxidation. The results suggest that AM may reduce the genotoxic effects and rates of congenital malformations caused by exposure to Cd in utero and that the antioxidant activity of this cyanobacterium could be responsible, at least in part, for producing this effect.

Protective Effect of Grapefruit Juice on the Teratogenic and Genotoxic Damage Induced by Cadmium in Mice

In the present study, we injected pregnant mice at Day 7 of gestation with cadmium chloride (CC) (1.5 mg/kg) intraperitoneally and determined its effect on the frequency of fetal malformations at Day 17 of pregnancy. On the same day, we also determined the level of micronucleated polychromatic erythrocytes (MNPEs) and of micronucleated normochromatic erythrocytes (MNNEs) in blood cells of both the mothers and their fetuses. A significant increase in the number of malformations was found, mainly exencephaly, micrognathia, ablephary, microphthalmia, and clubfoot, as well as a significant increase in the amount of MNPEs and MNNEs. In addition, pregnant mice were administered grapefruit juice (GJ) orally from Days 0 to 17 of the experiment (from 200 to 800 μL/g) to evaluate the potential of the juice in preventing the damage induced by CC. We found a dose-dependent decrease in the number of visceral and skeletal malformations, as well as in the number of MNPEs and MNNEs, in both the mothers and their fetuses. Furthermore, we determined the level of DNA oxidation by measuring levels of the adduct 8-hydroxy-2'-deoxyguanosine, and we found a significant increase in such level induced by CC; in contrast, there was a significant decrease when we added GJ. Therefore, the observed teratogenic and genotoxic protection can probably be related with the antioxidant potential of GJ.

Investigation on the protective effects of cranberry against the DNA damage induced by benzo[a]pyrene.

There are few reports that demonstrate the antigenotoxic potential of cranberries. Although the types of berry fruits consumed worldwide are many, this paper focuses on cranberries that are commonly consumed in Mexico (Vaccinium macrocarpon species). The purpose of the present study is to determine whether cranberry ethanolic extract (CEE) can prevent the DNA damage produced by benzo[a]pyrene (B[a]P) using an in vivo mouse peripheral blood micronucleus assay. The experimental groups were organized as follows: a negative control group (without treatment), a positive group treated with B[a]P (200 mg/kg), a group administered with 800 mg/kg of CEE, and three groups treated with B[a]P and CEE (200, 400, and 800 mg/kg) respectively. The CEE and benzo[a]pyrene were administered orally for a week, on a daily basis. During this period the body weight, the feed intake, and the determination of antigenotoxic potential were quantified. At the end of this period, we continued with the same determinations for one week more (recovery period) but anymore administration of the substances. The animals treated with B[a]P showed a weight increase after the first week of administration. The same phenomenon was observed in the lots combined with B[a]P and CEE (low and medium doses). The dose of 800 mg/kg of CEE showed similar values to the control group at the end of the treatment period. In the second part of the assay, when the substances were not administered, these experimental groups regained their normal weight. The dose of CEE (800 mg/kg) was not genotoxic nor cytotoxic. On the contrary, the B[a]P increases the frequency of micronucleated normochromatic erythrocytes (MNNE) and reduces the rate of polychromatic erythrocytes (PE) at the end of the treatment period. With respect to the combined lots, a significant decrease in the MN rate was observed from the sixth to the eighth day of treatment with the two high doses applied; the highest protection (60%) was obtained with 800 mg/kg of CEE. The same dose showed an anticytotoxic effect which corresponded to an improvement of 62.5% in relation to the animals administered with the B[a]P. In the second period, all groups reached values that have been seen in the control group animals. Our results suggest that the inhibition of clastogenicity of the cranberry ethanolic extract against B[a]P is related to the antioxidant capacity of the combination of phytochemicals present in its chemical composition.

Dietary supplementation with whey protein and ginseng extract counteracts oxidative stress and DNA damage in rats fed an aflatoxin-contaminated diet

Aflatoxins (AF) are among the most potent naturally occurring carcinogens and aflatoxin-B1 (AFB 1) is classified as a group-1 carcinogen. Since the ingestion of aflatoxins-contaminated food is associated with several liver diseases, the aim of the present study was to evaluate whether AF-induced damage in rats can be counteracted by feeding with whey-protein concentrates (WPC) and Korean ginseng extract (KGE). Eighty male Sprague-Dawley rats were divided into eight equal groups and treated daily for 30 days as follows: a control group (fed an AF-free diet), a group fed ad libitum an AF-contaminated diet (2.5 mg/kg diet), a group treated orally with WPC (0.5 ml/rat/day), a group treated orally with KGE (20 mg/kg body weight), a group treated orally with WPC + KGE, and three groups that were fed the AF-contaminated diet and were treated orally with WPC, KGE or WPC + KGE, respectively. Throughout the experimental period, animals received WPC or KGE during the consumption of their respective diet. Bone-marrow micronucleus formation, DNA fragmentation, fatty-acid synthesis (FAS) and phospholipid-hydroperoxide-glutathione-peroxidase ( PHGPx) mRNA expression, and oxidative stress were assayed in liver and testis. The results indicated that ingestion of aflatoxin resulted in a significant increase in micronucleated normochromatic erythrocytes (Mn-NCE) in bone marrow, DNA fragmentation, FAS mRNA expression and lipid peroxidation in both organs, and a significant decrease in micronucleated polychromatic erythrocytes/micronucleated normochromatic erythrocytes (PCE/NCE) ratio in bone marrow, PHGPx gene expression and GSH in liver and testis. Treatments with WPC and/or KGE had a significant effect on Mn-NCE or the PCE/NCE ratio in bone marrow. However, KGE or KGE + WPC increased PHGPx gene expression and GSH in testis accompanied with a significant decrease in lipid peroxidation in liver and testis and FAS-mRNA expression in liver. WPC, KGE or WPC + KGE treatments combined with exposure to an AF-contaminated diet restored all the test parameters towards control values, although they did not fully reverse the effects of the aflatoxins. It is suggested that the genotoxicity of aflatoxins can be in part prevented by dietary supplementation with WPC, KGE or their combination.

Micronuclei Induced by Imipramine and Desipramine in Mice: A Subchronic Study

Depression is a common disease that may cause severe damage to human health. Imipramine (IMI) and desipramine (DES) are medicaments used for treatment, yet studies on their genotoxic potential have given controversial results. Therefore, we designed the present assay to determine their effect as inducers of micronucleated polychromatic erythrocytes (MNPE) and micronucleated normochromatic erythrocytes (MNNE) in mice. The study was carried out in animals administered daily with the compounds for 4 weeks, and the determination of micronuclei was done each week. We also evaluated the bone marrow cytotoxicity induced by the chemicals. Besides, the same determinations were carried out in the following 4 consecutive weeks, but in this period the animals were not treated with the tested compounds. Our results showed a significant increase in both MNPE and MNNE induced by both compounds from the first week of administration. At the fourth week, IMI increased three times the control level, while the effect of DES was about seven times such level. In the second, 4-week phase, we observed a reduction in the rate of micronuclei approaching the control level. We also detected a bone marrow-mitotic division decrease by the evaluated chemicals. Our results point to the need for cautiousness in the clinical use of the compounds as well as for testing the effect in patients under treatment.

Frequency of Hprt mutant lymphocytes and micronucleated erythrocytes in p53‐haplodeficient mice treated perinatally with AZT and AZT in combination with 3TC

Azidothymidine (AZT) is a nucleoside reverse transcriptase inhibitor (NRTI) that is used for reducing mother-to-child transmission of human immunodeficiency virus I. Combinations of AZT and 3'-thiacytidine (3TC) are even more effective than AZT alone. AZT, however, is a mutagen and carcinogen in rodent models and 3TC can increase the genotoxicity of AZT. Since p53 plays a key role in human and mouse tumorigenesis, p53-haplodeficient mice are currently being evaluated as a model for assessing the carcinogenicity of perinatal exposure to NRTIs. In the present study, male C57BL/6 p53(+/+) and p53(-/-) mice were mated with C3H p53(+/+) females; the pregnant females were treated on gestation day 12 through parturition with 40, 80, and 160 mg/kg of AZT or a combination of 160 mg/kg AZT and 100 mg/kg 3TC (AZT-3TC); the p53(+/+) and p53(+/-) offspring were treated daily after birth through postnatal day (PND) 28. The frequencies of micronucleated reticulocytes (MN-RETs) and micronucleated normochromatic erythrocytes (MN-NCEs) were determined on PND1, PND10, and PND28; the frequency of Hprt mutant lymphocytes was measured on PND28. The frequencies of MN-RETs and MN-NCEs were increased in treated animals at all time points; there were no differences in the responses of p53(+/+) and p53(+/-) animals treated with identical doses of NRTIs. After correction for clonal expansion, both AZT and AZT-3TC treatments induced small but significant increases in the frequency of Hprt mutant lymphocytes in p53(+/-) mice, but not in p53(+/+) mice. The data indicate that p53 haplodeficiency affects the genotoxicity of NRTIs; thus, p53(+/-) mice may be a sensitive model for evaluating the carcinogenicity of perinatal exposure to NRTIs.

Antigenotoxic effect of Saccharomyces cerevisiae on the damage produced in mice fed with aflatoxin B 1 contaminated corn

The potential of Saccharomyces cerevisiae (Sc) was evaluated for reducing the micronucleated normochromatic erythrocytes (MNNE) rate in mice fed AFB 1 contaminated corn. The study included two groups fed AFB 1 contaminated corn (0.4 and 0.8 mg/kg), a control fed uncontaminated corn, another group fed uncontaminated corn and 0.3% of Sc (1 × 10 8 live cells/g), and two groups fed AFB 1 contaminated corn (0.4 and 0.8 mg/kg) plus 0.3% Sc. Weight and MNNE were determined weekly for six weeks. Subsequently, the same determinations were made for another three-week period, but in mice receiving only a normal diet, without AFB 1 and Sc. Results in the first period revealed the following: control and Sc fed mice had similar constant weight increase, and low MNNE rate; mice fed only AFB 1 showed weight decrease and significant MNNE increase; finally, Sc improved weight gain and reduced MNNE produced by AFB 1. In the second period, results exhibited a tendency similar to that of the previous phase in the control and Sc fed mice; the weight and MNNE values improved in the other groups. We also determined the capacity of Sc for adsorbing and modifying the mycotoxin structure. The mixture was filtered to obtain two phases, and AFB 1 content was measured. Sc revealed a potent adsorbent capacity; however, chromatographic determination suggested no structural modification.

Evaluation of the radioprotective effect of Liv 52 in mice

Liv 52 is a mixture of botanicals that is used clinically to treat various hepatic disorders. In this study, the radioprotective activity of Liv 52 was evaluated in mice given whole-body exposure to different doses of gamma-radiation. In addition, a series of studies was conducted to explore the mechanism of radioprotection. Radioprotection was evaluated by the ability of Liv 52 to reduce both the frequency of bone marrow micronucleated erythrocytes and the lethality produced by (60)Co gamma-radiation. Mice were treated by oral gavage once daily for seven consecutive days with 500 mg/kg body weight Liv 52 or carboxymethylcellulose vehicle prior to radiation. Micronucleated polychromatic erythrocytes (MPCEs), micronucleated normochromatic erythrocytes (MNCEs), and the PCE/NCE ratio were measured at 0.25-14 days after exposure to whole-body radiation doses of 0, 0.5, 1.5, 3.0, or 4.5 Gy; animal survival was monitored after doses of 7, 8, 9, 10, 11, or 12 Gy. Pretreatment of mice with Liv 52 significantly reduced the frequency of radiation-induced MPCEs and MNCEs. Irradiation reduced the PCE/NCE ratio in a dose-related manner for up to 7 days following irradiation; Liv 52 pretreatment significantly mitigated against these reductions. Liv 52 treatment also reduced the symptoms of radiation sickness and increased mouse survival 10 and 30 days after irradiation. Liv 52 pretreatment elevated the levels of reduced glutathione (GSH), increased the activities of glutathione transferase, GSH peroxidase, GSH reductase, superoxide dismutase, and catalase, and lowered lipid peroxidation (LPx) and the activities of alanine amino transferase and aspartate aminotransferase 30 min after exposure to 7 Gy of gamma-radiation. Liv 52 pretreatment also reduced radiation-induced LPx and increased GSH concentration 31 days following the exposure. The results of this study indicate that pretreatment with Liv 52 reduces the genotoxic and lethal effects of gamma-irradiation in mice and suggest that this radioprotection may be afforded by reducing the toxic effects of the oxidative products of irradiation.

Genotoxicity induced by drug-drug interaction between the antidepressant sertraline and the antibiotic erythromycin in mice bone marrow cells.

Drug-drug interaction represents a widely distributed health problem. The pharmacological action and side effects of two or more drugs can act additively or antagonistically. The present study was designed to evaluate the possible genotoxicity of concurrent treatment with the antidepressant sertraline, one of the serotonin reuptake inhibitors (SSRI) and the broad spectrum macrolide antibiotic erythromycin. Sertraline and erythromycin are metabolized through CYP3A4 which is one of the cytochrome P-450 enzymes in liver and are responsible for the metabolism of large number of endogenous substrates and therapeutic agents. The frequency of micronucleated polychromatic erythrocytes (MNPCEs), micronucleated normochromatic erythrocytes (MNNCEs) and the ratio PCE/NCE were evaluated to measure the genotoxicity of separate and combined treatment with the tested two drugs. Clinical doses of both sertraline (0.71 mg /kg b.w.) and erythromcyin strearate (14.30 mg / kg b.w.) were used. Groups of animals received single separate or combined doses of either sertraline and/or erythromycin, and sacrificed after 24 hours. Other groups of mice were treated in the same way but for five consecutive days and sacrificed 24 hours after the last injection. In all treated groups, the percentage of PCEs increased significantly when compared with that of the negative control group which may indicate a stimulation of proliferative activity to an early phase of cell depletion. The genotoxicity of multiple treatment for 5 consecutive days with sertraline alone or in combination with erythromcyin was expressed in increased number of MNPCEs. The observed increased genotoxicity after multiple combined treatment with sertraline and erythromycin may indicate increased risk of toxicity-based drug-drug interaction. This toxicity may be due to the ability of sertraline and erythromycin to inhibit the activity of CYP3A4 which lead to a prolonged storage period of drugs in the body and hence increased toxicity.

Genotoxicity induced by drug-drug interaction between the antidepressant sertraline and the antibiotic erythromycin in mice bone marrow cells.

Drug-drug interaction represents a widely distributed health problem. The pharmacological action and side effects of two or more drugs can act additively or antagonistically. The present study was designed to evaluate the possible genotoxicity of concurrent treatment with the antidepressant sertraline, one of the serotonin reuptake inhibitors (SSRI) and the broad spectrum macrolide antibiotic erythromycin. Sertraline and erythromycin are metabolized through CYP3A4 which is one of the cytochrome P-450 enzymes in liver and are responsible for the metabolism of large number of endogenous substrates and therapeutic agents. The frequency of micronucleated polychromatic erythrocytes (MNPCEs), micronucleated normochromatic erythrocytes (MNNCEs) and the ratio PCE/NCE were evaluated to measure the genotoxicity of separate and combined treatment with the tested two drugs. Clinical doses of both sertraline (0.71 mg /kg b.w.) and erythromcyin strearate (14.30 mg / kg b.w.) were used. Groups of animals received single separate or combined doses of either sertraline and/or erythromycin, and sacrificed after 24 hours. Other groups of mice were treated in the same way but for five consecutive days and sacrificed 24 hours after the last injection. In all treated groups, the percentage of PCEs increased significantly when compared with that of the negative control group which may indicate a stimulation of proliferative activity to an early phase of cell depletion. The genotoxicity of multiple treatment for 5 consecutive days with sertraline alone or in combination with erythromcyin was expressed in increased number of MNPCEs. The observed increased genotoxicity after multiple combined treatment with sertraline and erythromycin may indicate increased risk of toxicity-based drug-drug interaction. This toxicity may be due to the ability of sertraline and erythromycin to inhibit the activity of CYP3A4 which lead to a prolonged storage period of drugs in the body and hence increased toxicity.

Micronucleated erythrocyte frequency in control and azidothymidine-treated Tk+/+, Tk+/− and Tk−/− mice

The first step in the activation of the anti-retroviral nucleoside analogue azidothymidine (AZT) involves its conversion to a 5′-monophosphate. In this study, we have evaluated the role of cytosolic thymidine kinase (Tk), the major enzyme involved in phosphorylating thymidine and its analogues, in the nuclear DNA damage produced by AZT in neonatal mice. Tk +/+, Tk +/− and Tk −/− mice were treated intraperitoneally with 200 mg/kg/day of AZT on postnatal days 1 through 8, and micronuclei were measured in peripheral blood 24 h after the last dose. AZT treatment increased the micronucleus (MN) frequencies to similar extents in both the reticulocytes (RETs) and normochromatic erythrocytes (NCEs) of Tk +/+ and Tk +/− mice; AZT did not increase the frequency of micronucleated RETs (MN-RETs) or micronucleated NCEs (MN-NCEs) in Tk −/− mice. Unexpectedly, neonatal Tk −/− mice treated with the vehicle had significantly elevated MN frequencies for both RETs and NCEs relative to Tk +/+ and Tk +/− mice (e.g., ∼3.4% MN-RETs and ∼4.8% MN-NCEs in Tk −/− mice versus ∼0.7 and ∼ 0.6% MN-RETs and MN-NCEs in neonatal Tk +/+ mice). Additional assays performed on untreated Tk −/− mice showed that elevated spontaneous MN frequencies persisted until at least 20 weeks of age, which approaches the average lifespan of Tk −/− mice. These results indicate that metabolism by Tk is necessary for the genotoxicity of AZT in neonatal mice; however, the genotoxicity of AZT is not altered by reducing the Tk gene dose by half. The elevated spontaneous MN frequencies in Tk −/− mice suggest the presence of an endogenous genotoxic activity in these mice.

The in vivo dose rate effect of chronic gamma radiation in mice: translocation and micronucleus analyses

The in vivo effects of chronic, ultra low dose rates of gamma radiation in mice were evaluated using fluorescence in situ hybridization and the in vivo micronucleus test. SWR×C57BL/6 mice were divided into nine exposure groups and continuously exposed to 0.5, 2.0 or 4.0 cGy 137 Cs per day for 30, 60 or 90 days; unexposed control mice were also included. Following exposure, blood samples were taken from each animal and the frequencies of micronucleated polychromatic erythrocytes (MPCE) and micronucleated normochromatic erythrocytes (MNCE) were determined using flow cytometry. Peripheral blood lymphocytes were cultured and analyzed by chromosome painting to determine translocation frequencies. A significant dose rate response was seen in translocations and both MPCE and MNCE. Comparisons were made between the three chronic dose rates and it was determined that there was no significant difference among translocation frequencies for each rate. However, a significant difference was found between the chronic exposures reported here and the fractionated daily exposures reported previously. Dose rate reduction effects, ranging from 3 at low doses to 14 at high doses, were found for chronic versus acute exposures. The possibility of gender effects was investigated in both micronucleus and translocation data. No gender effect was found in translocation induction, but a slight effect was suggested in micronucleus induction.

Teniposide (VM-26) treatment enhances the radiation-induced micronuclei in the bone marrow of mouse

The effect of Teniposide (VM-26) pretreatment was studied on the micronuclei induction in the bone marrow of mice exposed to 0, 0.5, 1, 2 and 3 Gy of gamma radiation at 12, 24 and 36 h post-irradiation. Administration of 0.05 mg/kg body weight of VM-26 to mice before irradiation resulted in the significant enhancement of micronucleated polychromatic erythrocytes (MPCE) at 12, 24 and 36 h post-irradiation. Highest elevation in the frequency of MPCE was observed in VM-26+irradiation group after exposure to 0.5 Gy when compared to concurrent DDW+irradiation group. This increase was two fold higher in VM-26+irradiation group at 12 and 24 h, while it was 3 fold higher at 36 h post-irradiation compared to DDW+irradiation group. The peak frequency of MPCE was observed at 24 h post-irradiation in both groups, which declined thereafter. The frequency of micronucleated normochromatic erythrocytes (MNCE) increased in a dose dependent manner in both DDW+irradiation and VM-26+irradiation groups. However, the frequency of MNCE was significantly higher in the latter when compared to the former group. The frequency of MNCE exhibited a continuous elevation up to 36 h post-irradiation in both DDW+irradiation and VM-26+irradiation groups. Treatment of mice with teniposide before irradiation resulted in a significant decline in the PCE/NCE ratio compared to DDW+irradiation group. The PCE/NCE ratio continued to decline up to 36 h post-irradiation in both the groups. The dose response for MPCE and PCE/NCE ratio was linear quadratic, while it was linear for MNCE.