Age- and sex-related differences in sensitivity to hepatotoxic action of estragole in mice

As determined by blood activity of alanine- and aspartate aminotransferases, intraperitoneal injection of estragole in subcarcinogenic dose 300 mg/kg does not damage the liver of suckling off-spring of both sexes and of adult SWR/J males but drastically damages it in mature females of this strain. Castration only slightly decreases the resistance of males to hepatotoxic action of estragole but significantly increases it in females; exogenous administration of estradiole benzoate to castrated males decreases their resistance to the hepatotoxin, whereas administration of testosterone propionate to ovariectomyzed females does not elevate it. Morphologically, estragole damages the same number of liver cells in females and males, but in males it induces mostly hydropic degenerative, and in females--necrotic changes of hepatocytes.     

The dominant lethal effect of dietary triethylenemelamine.

Triethylenemelamine (TEM) was administered in the diet to adult male mice at doses of 0.1, 0.3, 1, 10 or 50 mg/kg body weight for 45 days or at doses of 0.1 or 0.3 mg/kg b.w. for 10 days. As a comparison, male mice were treated intraperitoneally with 5 daily doses of 0.25 or 0.5 mg TEM/kg b.w. At the end of the treatment period, males were mated sequentially with 2 untreated virgin females each for 2 or 3 weeks. Near mid-pregnancy the number of implantation sites and fetal deaths were determined. TEM, administered in the diet at 10 or 50 mg/kg b.w. for 45 dyas, was lethal to male mice. Surviving males from the 1 mg/kg level failed to impregnate any females during the two matings. TEM, given in the diet at 0.1 or 0.3 mg/kg for 10 or 45 dyas, decreased fertility and increased dominant lethal mutations in a dose and time dependent manner. These results were comparable to those obtained from males treated i.p. with TEM at 0.25 or 0.5 mg/kg b.w.     

A subchronic toxicity study of elemental Nano-Se in Sprague-Dawley rats

The subchronic toxicity of Nano-Se was compared with selenite and high-selenium protein in rats. Groups of Sprague-Dawley rats (12 males and 12 females per group) were fed diets containing Nano-Se, selenite and high-selenium protein at concentrations of 0, 2, 3, 4 and 5 ppm Se, respectively, for 13 weeks. Clinical observations were made and body weight and food consumption were recorded weekly. At the end of the study, the rats were subjected to a full necropsy, blood samples were collected for hematology and clinical chemistry determination. Histopathological examination was performed on selected tissues. At the two higher doses (4 and 5 ppm Se), significant abnormal changes were found in body weight, hematology, clinical chemistry, relative organ weights and histopathology parameters. However, the toxicity was more pronounced in the selenite and high-selenium protein groups than the Nano-Se group. At the dose of 3 ppm Se, significant growth inhibition and degeneration of liver cells were found in the selenite and high-selenium protein groups. No changes attributable to administration of Nano-Se at the dose of 3 ppm Se were found. Taken together, the no-observed-adverse-effect level (NOAEL) of Nano-Se in male and female rats was considered to be 3 ppm Se, equivalent to 0.22 mg/kg bw/day for males and 0.33 mg/kg bw/day for females. On the other hand, the NOAELs of selenite and high-selenium protein in males and females were considered to be 2 ppm Se, equivalent to 0.14 mg/kg bw/day for males and 0.20 mg/kg bw/day for females. In addition, studies have shown that Nano-Se has a similar bioavailability in rat, and much less acute toxicity in mice compared with selenite. In conclusion, Nano-Se is less toxic than selenite and high-selenium protein in the 13-week rat study.     

Studies on germinal effects of quercetin, a naturally occurring flavonoid

Quercetin (3,3',4',5,7-pentahydroxyflavone) is one of the most widely occurring flavonoids ingested by man in food. It has been shown to be mutagenic in prokaryotes as well as in in vitro mammalian cell lines. In view of the unavoidability of ingesting it via a normal diet, there is a need to assess the potential genetic risk to man, due to flavonoid ingestion, using whole animal assays. Dominant lethal studies have been carried out in adult Swiss male mice and Wistar male rats to investigate the germinal effects of quercetin. Adult Swiss males were treated with 200, 300 or 400 mg/kg of quercetin dissolved in 60% dimethyl sulfoxide, intraperitoneally. In the rat study, 200 and 300 mg/kg of quercetin were used. Individually caged males were paired with untreated females for a week and six sequential matings were carried out. Two independent experiments in mice and a single experiment in rats constituted the study. Females were evaluated for inducted dominant lethality during the midterm of pregnancy. At 200 mg/kg dose of quercetin, there were no significant differences between control and the test group in pregnancy, total or live implantations in mice or rats during the whole test period that could be attributed to the flavonoid exposure. In mice at 300 and 400 mg/kg of quercetin, there was a profound reduction in fertility of the males during all six matings. The number of total and live implantations also decreased, particularly at the 400 mg/kg dose, although the sample size was too small to be statistically significant. Contrary to this, the rat study did not show any impairment of fertility, nor was there any substantial suppression of total and live implantations at the highest (300 mg/kg) dose tested. There were no significant differences between control and treated groups with regard to the number of dead implantations at any dosage level at any stage of the study in mice and rats. Thus, no post-implantation losses--a reliable measure of dominant lethal mutations--were induced by quercetin in mice or rats. The loss of fertility could be due to germinal cytotoxicity, oligospermia or impairment of fertilizing ability of the treated animals.(ABSTRACT TRUNCATED AT 400 WORDS)     

Development and inducibility of the hepatic and renal hippurate-synthesizing system in sparse-fur (spf) mutant mice with ornithine transcarbamylase deficiency

The development of the hepatic and renal hippurate-synthesizing system, as represented by the overall reaction of the benzoyl CoA: glycine N-acyltransferase (EC 2.3.1.13) was studied in 0, 4, 8, 13, 17, 21-day and 8-week old sparse-fur (spf) mutant mice with X-linked ornithine transcarbamylase (OTC) deficiency. The enzyme system in mutant males (spf/Y) showed a retarded development in both liver and kidney cortex, which was statistically significant between 13 and 21 days of age, as compared to normal males (+/Y). Hippurate synthesis in preparations from adult (8-week old) spf/Y mice was not significantly different than the normal. Daily intraperitoneal injections of sodium benzoate in increasing concentrations (125-375 mg/kg), given between 17 and 21 days, did not cause any induction in spf/Y or +/Y mice. However, intraperitoneal sodium phenobarbital (80 mg/kg) increased the specific and total activities of the hepatic enzyme system in normal +/Y mice significantly. spf/Y tolerated a dose of 40 mg/kg only, which resulted in no significant increase of hepatic enzyme activity. The results indicate that barbiturates may induce the hippurate-synthesizing system, whereas benzoate treatment has no effect on changing its developmental profile.     

Antifertility effect of busulfan and DL-6-(N-2-pipecolinomethyl)-5-hydroxy-indane maleate (PMHI) in coyotes (Canis Latrans )

Antifertility effects of busulfan were evaluated using adult coyotes. In addition, antifertility effects of PMHI were evaluated in adult males. Adult males and females were alloted randomly to the following treatments: (1) untreated control, (2) a single oral dose of 3 mg busulfan/kg of body weight (BW) or (3) two oral doses of 3 mg busulfan/kg BW given nine days apart. The untreated males were used as controls in both experiments. Additional male coyotes were allotted randomly to PMHI treatments as follows: (1) a single oral dose of 2 mg PMHI/kg BW, or (2) two oral doses of 1 mg PMHI/kg BW given seven days apart. Blood samples were taken from females and serum analyzed for progesterone by radioimmunoassay. Males were hemicastrated (left testicle) 30 days after onset of treatment. The right testicle was removed 30 days later. Testes and epididymides were fixed in 10% buffered formalin and prepared for histologic examination. For females developing corpus luteum (CL), the maximum peak progesterone concentration for those given two doses of busulfan was less (P<0.05) than that for untreated controls and single-dose females (16.9, 22.4 and 26.3 ng/ml, respectively). The double treatment of busulfan prevented more females (4 of 10) from developing CL (P<0.08) than controls (0 of 7) or single-dose females (1 of 9). None of the busulfan-treated male coyotes had histologic evidence of spermatogenesis 60 days after the onset of treatment. The oral dose or doses of PMHI did not result in complete degeneration of seminiferous tubules. Busulfan given orally did not cause any adverse reactions, but orally administered PMHI often induced vomiting within 18 min after treatment. We conclude that busulfan is capable of affecting male and female reproductive parameters, but PMHI appears to have little effect on spermatogenesis in coyotes when given orally in a single- or a double-dose.     

Trypanocidal activity of organotin chlorides on Trypanosoma brucei-infected mice

The organotin compounds dibutyltin (DBTC) and diphenyltin dichlorides (DPTC) were tested for trypanocidal activity on a Trypanosoma brucei-infected mice model. At a dose of 10 mg DBTC and 15 mg DPTC/kg/day for five consecutive days, they cleared the parasites from the peripheral blood of the infected mice. Subinoculation of some healthy mice with the homogenates of liver, spleen, kidney, cerebrospinal fluid and blood from the mice considered cured, showed a few cases of relapse. The LD50 of DBTC and DPTC are 90 mg/kg and 75 mg/kg respectively.     

Role of maternal plasma corticosterone elevation in the teratogenicity of secalonic acid D in mice

Secalonic acid D (SAD) is a teratogenic mycotoxin that causes cleft palate in the offspring of treated pregnant mice. To investigate the role of maternal corticosterone in the teratogenicity of SAD, pregnant CD-1 mice were treated with 30 mg/kg of SAD i.p. on day 11 of pregnancy in either 5% (w/v) NaHCO3 or 20% (v/v) dimethyl sulfoxide (DMSO) in NaHCO3. Radioimmunoassay (RIA) was performed to determine plasma corticosterone at 24, 48, 72, and 96 hr after dosing. No interference by EDTA, SAD, DMSO, or pentobarbital was noticed on the RIA. Significant (P less than .01) elevations in plasma corticosterone concentrations were seen 24 and 48 hr following dosing of SAD in NaHCO3 with concentrations reaching a peak just prior to the onset of shelf elevation and fusion. Simultaneous treatment with DMSO, an agent known to antagonize the teratogenic effect of SAD, completely abolished the SAD-induced corticosterone elevation at the 24 hr time point and significantly (P less than .01) reduced it at the 48 hr time point. To evaluate the specificity of the role of corticosterone in the teratogenicity of SAD, plasma samples from mature males similarly treated with either single or multiple doses of SAD ranging from 15 to 45 mg/kg were assayed for corticosterone. A dose of SAD comparable to that used in the pregnant females failed to significantly change plasma corticosterone concentrations in the males. An elevation corresponding only to 75% of that in the females was seen in males receiving multiple doses of SAD totaling three times the dose used in the females. As with females, DMSO completely abolished plasma corticosterone elevation by SAD in the males. These results demonstrate, for the first time, the effect of SAD on a mammalian endocrine system and provide evidence for a specific involvement of elevated maternal plasma corticosterone concentrations in SAD teratogenicity.     

On the differential responsiveness of males and females in the micronucleus assay

The primary question asked was whether the increased sensitivity of female mice to the induction of micronuclei by ethyl methanesulphonate, compared to males, would vanish if the doses were adjusted for any difference in the LD50 between the sexes. The second question was whether the frequency of micronuclei after 4 daily treatments would differ from 2 daily treatments. We measured the LD50 in the two sexes separately and found the female value to be lower. We also repeated the micronucleus measurements in each sex separately. At any given dose expressed in mg/kg the response in females was greater than in males. This was still true when the dose was expressed as a fraction of the LD50, but the difference was reduced. The uncertainty in the LD50 measurements was such that there may be no meaningful difference between males and females when the dose is expressed in this way. The 2-day and 4-day results differed very little for ethyl methanesulphonate, but were quite different for the positive control, dimethylbenz[a]anthracene, being higher at 4 days than at 2 days. We argue that the results of our experiments, which confirm the results of others, demonstrate the advisability of using both sexes in the assay.     

Efficacy of ivermectin against Syphacia obvelata (Nematoda) in mice

Ivermectin was evaluated against natural and artificial pinworm (Syphacia) infections in mice. Ivermectin given in the diet for 6 days at 0.0005% was 99% effective against both immature and adult worms. A diet level of 0.0004% reduced immature and mature pinworm by 99 and 75%, respectively but 0.0001% was inactive. One oral dose of 2.0 mg/kg was 100 and 97% effective against gravid females and immature worms, respectively. A dose of 1.0 mg/kg was 96 and 66% effective against the same parasitic stages. A similar effect was observed against adult male worms where 94 and 86% were removed by one oral dose of ivermectin at 2.0 and 1.0 mg/kg, respectively.     

Effects of thalidomide on reproductive function and early embryonic development in male and female New Zealand white rabbits

BACKGROUND : The present work was performed to determine the effect of thalidomide exposure on reproductive function and early embryonic development. METHODS : Twenty‐five female New Zealand White rabbits were orally gavaged with 0, 10, 50, or 100 mg/kg/day thalidomide 14 days prior to mating through to gestation day 7 for a total of 22 days. Treated females were Caesarean‐sectioned approximately 29 days after the date of attempted mating. Following mating with treated females, male rabbits (25/dose) were gavaged with 0, 30, 150, or 500 mg/kg/day beginning 14 days prior to mating with a group of untreated females (25/dose). Doses were administered through mating until the day before sacrifice for a minimum of 56 days. Untreated females were Caesarean‐sectioned 29 days after the last attempted mating. Comprehensive necropsy and histopathology of the reproductive system were performed. RESULTS : Treated females had reduction in body weight gain during gestation. Mating and pregnancy parameters were unaffected by thalidomide. At 100 m/kg, litter averages for corpora lutea, implantations, litter sizes, does with viable fetuses and live fetuses decreased and the number of early resorptions, does with any resorptions, does with all conceptuses resorbed, and the percent resorbed conceptuses per litter increased. The number of early resorptions, the average number of early resorptions per litter, and the percent resorbed conceptuses per litter increased at 10 and 50 mg/kg. There were no thalidomide‐related external fetal malformations. Mating and fertility in male rabbits were unaffected by thalidomide. There was an increased incidence of flaccid testes at 150 and 500 mg/kg and of bilateral small testes in all treated groups. At 500 mg/kg, there was degeneration of the germinal epithelium of the testicles with an increase in multinucleated giant cells in seminiferous tubule and a loss of round and elongating spermatids. CONCLUSIONS : Thalidomide had no adverse effects on mating and fertility in male and female rabbits dosed up to 500 and 100 mg/kg/day, respectively, for 14 days prior to mating. After 56 day of dosing, histopathologic changes with no associated sperm abnormalities were observed in the testicles. Embryonic development NOAEL for treated females mated to untreated males was <10 mg/kg. Corresponding fertility NOAEL for treated males mated to untreated females was 500 mg/kg. Birth Defects Res B 71:1–16, 2004. © 2004 Wiley‐Liss, Inc.     

Mutagenicity evaluation of HC Blue No. 1 and HC Blue No. 2, I. Effect on the induction of micronuclei in mouse bone marrow cells

Two hair-dye chemicals, HC Blue No. 1 and HC Blue No. 2, were assessed for the ability to produce chromosome breakage and/or spindle malformation in vivo by evaluating the capacity of these compounds to induce micronuclei in polychromatic erythrocytes of mouse bone marrow. Initial studies were conducted in ICR male and female mice given a single intraperitoneal dose of 1000, 500 or 250 mg/kg body weight and examined for micronucleus induction 24 or 48 h later. Activity was observed in female mice given 1000 mg/kg of HC Blue No. 1 at the 24-h harvest time. A questionable response was noted with HC Blue No. 2 in males at the 1000 mg/kg, 24-h time point. No activity was observed in either sex at the 48-h harvest time. In a second set of studies, mice from two strains, ICR and CD-1, were administered a single intraperitoneal dose of 1000 mg/kg of each chemical and the bone marrow was extracted 24 h later. In these experiments, HC Blue No. 1 again produced a statistically significant elevation of micronuclei in female ICR mice. No significant effect was observed in CD-1 mice of either sex. HC Blue No. 2 did not produce any significant elevation of micronuclei in either sex of ICR or CD-1 mice.     

Studies of potential filaricides: Part 14--Activity of 1-iso-butoxycarbonyl-4-methylpiperazine against experimental filariasis

The synthesis and filaricidal activity of 1-iso-butoxycarbonyl-4-methylpiperazine against Litomosoides carinii in Sigmodon hispidus and Dipetalonema viteae in Mastomys natalensis is reported. At an intraperitoneal or oral dose of 3 mg/kg given for 6 days, the compound removed 91% of the circulating microfilariae but had no effect on adult L. carinii. However, it killed all microfilariae and adults of D. viteae at a subcutaneous dose of 50 mg/kg given for 6 days. The compound also possessed chemoprophylactic activity against the larvae of L. carinii and D. viteae at a dose of 30 and 50 mg/kg respectively.     

Maternal glucocorticoid hormones as a factor mediating the effect of prenatal stress on offspring anxiety

The plus-maze behavior was studied in offsprings of female rats subjected to immobilization stress on the 15-18 days of pregnancy. Prenatal stress decreased the level of anxiety in males and increased in females. The blockade of the mother's stress-induced glucocorticoid secretion by prior adrenalectomy and subsequent corticosterone injection during immobilization in a low dose (0.3 mg/kg) prevented the behavioral disorders in offsprings. In case of a higher dose of corticosterone (3 mg/kg) injection, the behavior of offsprings was the same as that of offsprings of the intact mothers subjected to immobilization. The results suggest that the stress-induced increase in maternal glucocorticoid level may be the mechanism by which prenatal stress impairs the development of sex differences in rat anxiety behavior.     

Differential regulation of cytochrome P450 3A1 and P450 3A2 in rat liver following dexamethasone treatment

Induction of P450 3A1 and P450 3A2 was studied in adult rat liver following treatment with a single high dose of dexamethasone (DEX). The increase of both P450 3A1 and 3A2 occurred at the level of mRNA as well as protein. P450 3A isozymes thus induced were catalytically active. No constitutive expression of P450 3A1 mRNA or protein was observed in males or females. Constitutive expression of P450 3A2 mRNA and protein was observed in males but not in females. Additionally, in females, P450 3A2 was almost nondetectable compared to that in males, at any dose of DEX. A time course study following DEX treatment showed that P450 3A1 mRNA and protein were detectable in both sexes at 12 hours, increased until 48 hours, and then declined. The decline was more rapid in males. P450 3A2 mRNA and protein increased as early as 3 hours, increased further up to 48 hours, and slowly declined thereafter. A dose-response study indicated that P450 3A1 mRNA and protein progressively increased in both sexes from a dose of 30 mg/kg. In contrast, P450 3A2 mRNA and protein in males did not increase up to a dose of 30 mg/kg but increased at higher doses. Total P450 content and P450 3A catalytic activity were also found to increase with time and dose. © 1996 John Wiley & Sons, Inc.     

Mutagenicity of Ascaris chymotrypsin inhibitor in germ cells of mice

Chymotrypsin inhibitor isolated from Ascaris suum (ACHI) was tested for the induction of dominant lethal mutations in male mice. Dominant lethal effects of ACHI for the main stages of germ cell development were analyzed by mating at specific time points after dosing. Two groups of adult BALB/c males received 24 or 40 mg per kilogram body weight (BW) per day intraperitoneal (IP) injection of ACHI in sterile phosphate-buffered saline (PBS) for five consecutive days (subacute exposure). Males from a third group were administered single IP injections of ACHI—60 mg/kg BW (acute exposure). The control group received concurrent injections of PBS for five successive days. After the last dose, each male was mated with two untreated females. For fractionated examination with regard to successive germ cell stages (spermatozoa, spermatids, spermatocytes, spermatogonia), every second week, two other untreated virgin females were placed with each male for mating. The uteri of the females were inspected on the 15th day of gestation, and preimplantation loss and postimplantation loss determined from dominant lethal parameters. Exposure of mice germ cells to ACHI did not impair mating activity of males. Fertility index was reduced (P < 0.05) only for females mated at the third week with males exposed to the highest dose of ACHI. In the females bred to ACHI-treated males, significant (P < 0.05) increase in preimplantation loss was observed at postinjection weeks 1 (reflecting exposure to spermatozoa after single treatment and to spermatozoa or late spermatids after subacute dosing) and 3 (reflecting exposure to mid and early spermatids for acute dosing and to mid and early spermatids or late spermatocytes following acute treatment), regardless of dose and length of exposure to the inhibitor. At the 60-mg/kg-BW group, a significant increase of this parameter was also noted at week 5 (reflecting exposure to early spermatocytes). During mating days 15–21, a significant (P < 0.05) increase in postimplantation loss and dominant lethal effects were observed for all doses of ACHI. Acute ACHI exposure 5 weeks prior to mating resulted in dominant lethal effects in early spermatocytes. These preliminary data suggest that ACHI induces dominant lethal mutations at postmeiotic and meiotic stages of spermatogenesis, but spermatids are the most sensitive cell stage to the effect of ACHI. These results show that ACHI may be one of the factors causing disturbances in spermatogenesis leading to a reduction of host reproductive success.     

The genotoxic and cytotoxic effects of nicotine in the mouse bone marrow

The objective of the present study was to investigate the potential of nicotine to induce micronucleated polychromatic erythrocytes (MNPCE) in bone marrow of male and female mice. Cyclophosphamide at 40mg/kg was used as positive control clastogen. Single doses of 4, 8 or 16mg/kg nicotine were given via oral intubation and bone marrow was sampled at 18, 24, 30, 36 and 48h after treatment. Cyclophosphamide yielded the expected positive results. Despite the evident signs of acute toxicity shown by the animals, mainly at the 8 and 16mg/kg doses of nicotine, and the reduction in the % PCE, the results show that the MNPCE frequency in male and female mice was not affected by treatment with any of the selected doses of nicotine, in either of the sampling times 18 or 24h. However, at 30 and 36h after treatment, the MNPCE showed significant increases in both genders after doses of 8 and 16mg/kg. A sex-dependent response was recorded, with males having more MNPCE than females after treatment with 8 or 16mg/kg nicotine and sampling at 30h. However, at 36h more MNPCE were induced in females than in males, suggesting different degrees of dose interaction in the sexes under the conditions of the assay. The response was directly correlated with bone-marrow toxicity, as greater bone-marrow suppression was noted in females than in males when 36h samples were examined. By 48h recovery was observed even though the cytotoxicity was high. These findings suggest that nicotine at high doses and after prolonged time intervals is genotoxic and cytotoxic for mouse bone marrow.     

Verapamil contributes to the clastogenic effects of acrylamide, cyclophosphamide, and dioxidine on somatic cells of BALB/C and C57BL/6 mice

The chromosome aberration assay of metaphase bone marrow cells was used to study the clastogenic effects of acrylamide, cyclophosphamide, dioxidine, and their combinations with Verapamil (a calcium antagonist) in male BALB/C and C57BL/6 mice. Verapamil gavage at single (5 mg/kg) and repeated doses (2.5 and 5 mg/kg five times at 24-h intervals) significantly enhanced the clastogenic activity of acrylamide (50 and 100 mg/kg intraperitoneally) in BALB/C mice; in C57BL/6 mice, this effect was only observed when they received Verapamil at doses of 2.5 mg/kg for 5 days. Verapamil administered repeatedly (2.5–10 mg, gavage) significantly increased the clastogenic activity of cyclophosphamide (10 mg/kg intraperitoneally) in C57BL/6 mice. In BALB/C mice, this effect of Verapamil was only observed at a dose of 10 mg/kg (gavage). When injected intraperitoneally at a single dose of 0.1–0.4 mg/kg, Verapamil significantly enhanced the clastogenic activity of cyclophosphamide in mice of both strains. This calcium antagonist produced identical effects when administered to BALB/C mice intraperitoneally (2.5 and 5 mg/kg) and by gavage (5 mg/kg) and to C57BL/6 mice intraperitoneally (5 and 10 mg/kg) and by gavage (2.5 mg/kg). Repeated administration of Verapamil (at all doses tested) promoted the clastogenic effect of dioxidine (100 mg/kg intraperitoneally) on C57BL/6 mice, having no such influence on BALB/C mice. These results demonstrate the co-clastogenic activity of Verapamil in mice and suggest that its specific manifestations depend on the dose, method, and route of drug administration and the genotype of test animals.     

Genotoxicity and repair capability of Mus musculus DNA following the oral exposure to Tramadol

Tramadol is an analgesic and psychoactive drug that acts primarily upon the central nervous system where it alters brain function, resulting in temporary changes in perception, mood, consciousness and behavior. The aim of present study was to analyze the genotoxicity and repair capability of DNA after Tramadol exposure in albino mice (Mus musculus). For this purpose, forty mice were divided equally into four groups as; a control group (without drug) and three treatment groups that were treated with three doses of Tramadol as minimum dose group, Intermediate dose group and maximum dose group, corresponding to 25 mg/kg, 50 mg/kg and 75 mg/kg of body weight respectively. The dose was given orally for 15 days. After 15 days peripheral blood was drawn from half mice of each group and subjected to comet assay. While the remaining half mice were given a recovery period of 15 days and same procedure was used for blood collection and comet assay. Significant difference in various comet parameters was observed among control and exposed groups. Maximum damage was observed at highest concentration 75 mg/kg of Tramadol and minimum damage was observed at dose 25 mg/kg of Tramadol, while results of repaired mice group showed that repair capability of Tramadol was minor and recovery of Tramadol required a lot of time. It can be concluded that Tramadol cause genotoxicity that is dose dependent and has low repair capability.     

Verapamil contributes to the clastogenic effects of acrylamide, cyclophosphamide, and dioxidine on somatic cells of BALB/C and C57BL/6 mice

The chromosome aberration assay of metaphase bone marrow cells was used to study the clastogenic effects of acrylamide, cyclophosphamide, dioxidine, and their combinations with Verapamil (a calcium antagonist) in male BALB/C and C57BL/6 mice. Verapamil gavage at single (5 mg/kg) and repeated doses (2.5 and 5 mg/kg five times at 24-h intervals) significantly enhanced the clastogenic activity of acrylamide (50 and 100 mg/kg intraperitoneally) in BALB/C mice; in C57BL/6 mice, this effect was only observed when they received Verapamil at doses of 2.5 mg/kg for 5 days. Verapamil administered repeatedly (2.5-10 mg, gavage) significantly increased the clastogenic activity of cyclophosphamide (10 mg/kg intraperitoneally) in C57BL/6 mice. In BALB/C mice, this effect of Verapamil was only observed at a dose of 10 mg/kg (gavage). When injected intraperitoneally at a single dose of 0.1-0.4 mg/kg, Verapamil significantly enhanced the clastogenic activity of cyclophosphamide in mice of both strains. This calcium antagonist produced identical effects when administered to BALB/C mice intraperitoneally (2.5 and 5 mg/kg) and by gavage (5 mg/kg) and to C57BL/6 mice intraperitoneally (5 and 10 mg/kg) and by gavage (2.5 mg/kg). Repeated administration of Verapamil (at all doses tested) promoted the clastogenic effect of dioxidine (100 mg/kg intraperitoneally) on C57BL/6 mice, having no such influence on BALB/C mice. These results demonstrate the co-clastogenic activity of Verapamil in mice and suggest that its specific manifestations depend on the dose, method, and route of drug administration and the genotype of test animals.