Toxicity Assessment of Transfluthrin, Benzyl Butyl Phthalate, and 17ß-Estradiol on the Primary Fibroblast of the Striped Field Mouse, Apodemus agrarius.

Environmental pollution (EP) is a well-known threat to wild animals, but its toxicological impact is poorly understood. In vitro toxicity evaluation using cells of lower predators could be a promising way to assess and monitor the effects of EPs on whole wildlife populations that are related in the food web. Here, we describe EPs' toxic effect and mechanism in the primary fibroblast derived from the embryo of the striped field mouse, Apodemus agrarius. Characterization of the primary fibroblast was via morphology, genetics, immunocytochemistry, and stable culture conditions for optimal toxicity screening. Cell viability assays-MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and lactate dehydrogenase (LDH)-were performed to observe cytotoxicity, and quantitative PCR was conducted to confirm gene alteration by EP exposure. MTT and LDH assays confirmed the cytotoxicity of transfluthrin (TF), benzyl butyl phthalate (BBP), and 17ß-estradiol (E2) with IC50 values of 10.56 µM, 10.82 µM, and 24.08 µM, respectively, following 48-h exposures. mRNA expression of androgen-binding protein, growth hormone receptor, cytochrome C oxidase, and cytochrome P450-1A1 was induced after exposure to TF, BBP, and E2. We unveiled new EP mechanisms at the mammalian cellular level and discovered potential biomarker genes for monitoring of EPs. Based on our findings, we propose the primary fibroblast of A. agrarius as a valuable model to assess the toxicological effects of EP on wildlife.

Gone in 60 seconds: Sub-lethal Effects of Metofluthrin Vapors on Behavior and Fitness of Resistant and Field Strains of Aedes aegypti (Diptera: Culicidae).

Spatial repellents can reduce fecundity and interrupt oviposition behavior in Aedes aegypti. Yet, it is unclear if short exposure times, resistant phenotypes, and other aspects of spatial repellents can impact these effects on mosquito reproduction. To address these issues, pyrethroid susceptible, pyrethroid resistant, and field strains of Ae. aegypti were used to evaluate the extent to which fecundity and oviposition behavior are affected following metofluthrin exposure. Mosquitoes were exposed for 60 s to a sub-lethal dose (LC30) of metofluthrin before blood feeding and allowed 72 h to become gravid before evaluation in an oviposition bioassay for an additional 72 h. Metofluthrin-exposed susceptible, field, and to a lesser extent resistant strain Ae. aegypti showed oviposition across fewer containers, less egg yield, less egg viability, and reduced larval survivorship in hatched eggs compared to unexposed cohorts. Susceptible mosquitoes retained some eggs at dissection following bioassays, and in one case, melanized eggs retained in the female. Treated resistant and field strain F1 larvae hatched significantly earlier than unexposed cohorts and resulted in increased larval mortality in the first 3 d after oviposition. Upon laying, the treated field strain had incompletely melanized eggs mixed in with viable eggs. The treated field strain also had the lowest survivorship of larvae reared from bioassay eggs. These results indicate that metofluthrin could succeed in reducing mosquito populations via multiple mechanisms besides acute lethality. With the available safety data, pre-existing spatial repellent registration, and possibilities for other outdoor delivery methods, metofluthrin is a strong candidate for transition into broader mosquito abatement operations.

Photocatalytic degradation of rosuvastatin: analytical studies and toxicity evaluations.

Photocatalytic degradation of rosuvastatin, which is a drug that has been used to reduce blood cholesterol levels, was studied in this work employing ZnO as catalyst. The experiments were carried out in a temperature-controlled batch reactor that was irradiated with UV light. Preliminary the effects of the photocatalyst loading, the initial pH and the initial rosuvastatin concentration were evaluated. The experimental results showed that rosuvastatin degradation is primarily a photocatalytic process, with pseudo-first order kinetics. The byproducts that were generated during the oxidative process were identified using nano-ultra performance liquid chromatography tandem mass spectrometry (nano-UPLC-MS/MS) and acute toxicity tests using Daphnia magna were done to evaluate the toxicity of the untreated rosuvastatin solution and the reactor effluent.

Transfluthrin: comparative efficacy and toxicity of reference and generic versions.

Stringent requirements are in place for the evaluation and registration of new compounds with biocidal or pesticidal activities. However, the registration requirements for established compounds from new suppliers or for established compounds produced by a different manufacturing process have been less clear and ambiguity exists as to how 'equivalence of health hazards' can unequivocally be demonstrated analytically and by toxicological assays. The case presented in this analysis focuses on the chiral pyrethroid transfluthrin (TFL) synthesized by esterification of an acid chloride and alcoholic moiety. According to any modifications of the process of synthesis and purification, new potentially highly toxic and yet chemically reactive impurities in low concentrations (<0.1%) may be formed. Amongst these, that with the structural alert 'organic acid anhydride' was given heightened concern as the most potent putative toxicologically significant impurity. The course taken in this analysis focused on the comparison of reference TFL with commercialized generic TFL from two alternative manufacturing sources in India and China. Despite their apparent high racemic purity, TFLs from generic sources were biologically less effective, genotoxic in the Ames' assay, demonstrated sensory lung irritation and lung/skin sensitization in specialized bioassays. While the off-patent reference TFL was unequivocally negative in all assays (anhydride content not detectable, LOQ <0.01%), positive results with high batch-to-batch variability were a frequent outcome in generic TFLs. Tier I analytical assays failed to detect this relevant impurity in the absence of impurity-specific optimized analytical procedures. This finding suggests that a well-balanced combined approach of analytical and toxicological assays provides the best means to assure that all critical impurities are identified and accounted for. Similarly, putative 'structural alert'-based toxicity tests proved to be more predictive than any indiscriminant battery of standard bioassays commonly applied to demonstrate equivalence, such as acute oral/dermal toxicity and/or eye/skin irritation assays.

Toxicity and bioconcentration of the pharmaceuticals moxifloxacin, rosuvastatin, and drospirenone to the unionid mussel Lampsilis siliquoidea.

Pharmaceuticals and personal care products (PPCPs) and their metabolites are continually released from wastewater treatment plants into the aquatic environment; however, their impact on aquatic biota is poorly understood. This study examined the toxicity and bioconcentration of three pharmaceuticals: moxifloxacin, rosuvastatin, and drospirenone to the unionid mussel Lampsilis siliquoidea. Effects of moxifloxacin and rosuvastatin were assessed through aqueous 21-d static-renewal tests using 2-year-old mussels, at 0.01, 0.1, 1, 10 and 100mg/L (nominal concentrations). Following exposure, survival, behavior, algal clearance rate, hemocyte viability and density, and glutathione S-transferase (GST) activity were assessed. In addition, the acute (48 h) toxicity of moxifloxacin (0-100mg/L) and drospirenone (0-3mg/L) to glochidia (larval mussels) were examined. In 21 day exposures (2-yr old mussels), there were no differences in survival, oxygen consumption, hemocyte density, or GST activity over the range of concentrations examined; however, the proportion of time mussels spent filtering, and consequently the algal clearance rate, decreased at the higher moxifloxacin and rosuvastatin concentrations. Bioconcentration factors (BCFs) ranged between 0.03 and 70 for moxifloxacin, and between 0 and 0.05 for rosuvastatin for exposures up to 100mg/L. The BCF for moxifloxacin at the highest exposure concentration was lower than that at the mid-level concentrations, likely due to decreased filtering activity at the higher exposure levels. The feeding rates declined and the amount of time the subadult mussels spent with their valves closed increased at the higher moxifloxacin and rosuvastatin exposures. Glochidia viability did not vary with exposure to drospirenone, but declined at the highest moxifloxacin concentration, resulting in an EC50 of 120 mg/L. Overall, observed sublethal and lethal effects occurred at concentrations which exceed expected environmental concentrations through aqueous exposure, suggesting a low risk to freshwater mussels from these particular PPCPs.

Delayed reproductive development in pubertal male rats exposed to the hypolipemiant agent rosuvastatin since prepuberty.

Dyslipidemias are frequently found in children due to obesity, bad eating habits and the lack of physical exercises. Rosuvastatin acts as an HMG-CoA reductase inhibitor, decreasing total cholesterol and triglycerides. This study aimed to investigate initial sexual development and morphological aspect of the testis and epididymis in juvenile rats exposed to rosuvastatin since pre-puberty. Three groups were formed with newly weaned rats: control, whose rats received saline solution 0.9%, rosuvastatin at doses of 3 or 10 mg/kg daily by gavage, since post-natal day 21 until puberty onset. In the rosuvastatin-treated groups, the results demonstrated a trend toward a decrease in testosterone concentration, but below the significance level, as well as delays in both the age of puberty onset and in epididymal development. There were also testicular alterations that might be related to delayed puberty and decrease of serum testosterone. In conclusion, rosuvastatin administration to juvenile rats not only delayed puberty onset and epididymal development, but also impaired testicular and epididymal morphology.

Genotoxicity evaluation of HMG CoA reductase inhibitor rosuvastatin.

The genotoxic potential of rosuvastatin as one of the statin drugs was assessed by chromosomal aberrations (CAs), micronucleus (MN) and DNA damage by comet assay in the human peripheral blood lymphocytes. Rosuvastatin was used at concentrations of 0.0625, 0.125, 0.25, 0.5 and 1 µg/mL for these in vitro assays. In all assays, a negative and positive control were also included. CA frequencies were significantly increased in all concentrations at 24 hours and significantly increased in all concentrations except 0.0625 µg/mL at 48 hours, compared to the negative control. Rosuvastatin has a decreased mitotic index (MI) at 0.5- and 1-µg/mL concentrations at 24 hours and at 0.25, 0.5 and 1 µg/mL at 48 hours. A significant increase was observed for induction of MN in all treatments, compared to the negative control. Cytokinesis-block proliferation indices were not affected by treatments with rosuvastatin. In the comet assay, significant increases in comet tail length and tail moment were observed at 0.0625-, 0.5- and 1-µg/mL concentrations. Comet intensity was significantly increased in all concentrations except 0.0625 µg/mL. According to these results, rosuvastatin is cytotoxic and clastogenic/aneugenic in human peripheral lymphocytes. Further studies should be conducted in other test systems to evaluate the full genotoxic potential of rosuvastatin.

Toxicological effects of prolonged and intense use of mosquito coil emission in rats and its implications on malaria control.

Mosquito coil is a vector control option used to prevent malaria in low income counties, while some studies have addressed this issue, additional reseach is required to increase knowledge on the adverse health effects caused by the prolonged use of coils. In this study we investigated the toxicological effects of fumes from two locally manufactured mosquito coil insecticides (with pyrethroids: transfluthrin and d-allethrin as active ingredients) on male albino rats. For this, we recorded the haematological and biochemical indices, and made histopathology and mutagenicity evaluations in rats exposed to mosquito fumes during 2, 4, 8, 12 and 16 week periods. Haematological determination was performed using automated hematology analyzer to determine White Blood Cell (WBC), Packed Cell Volume (PCV), Red Blood Cell (RBC) and Platelet (PLT) counts, while biochemical evaluations were determined using available commercial kits. Gross histopathological changes were studied for the kidney, liver and lungs in sacrificed rats. The rat sperm head abnormalities assessment was used to evaluate mutagenicity. Mosquito coil fumes produced significant increase (P < 0.05) in the levels of total protein, total albumin and bilirubin, when animals were exposed from two weeks to 16 weeks with transfluthrin. Similarly, elevation in the activities of aspartate amino transferase, alanine amino transferase and alanine phosphatase, increased significantly in both insecticides. Increase in WBC, RBC and PCV were recorded for all the exposure periods, however PLT count showed no significant increase (P > 0.05). Mutagenicity assessment revealed sperm abnormality was statistically significant (P < 0.05) compared with the control at 8, 12 and 16 weeks post exposure to transfluthrin. Histological studies revealed severe lung damage evidenced by interstitial accumulations, pulmonary oedema and emphysema in exposed rats. Intracellular accumulations and severe sinusoidal congestion of liver cells were observed from 12 weeks exposure, indicating liver damage. Our studies indicate that mosquito coil fumes do initiate gradual damage to the host. These pathological effects must be taken into consideration by the malaria control program, particularly when regulating their long term and indoor usage.

Toxicological effects of prolonged and intense use of mosquito coil emission in rats and its implications on malaria control / Efectos toxicológicos del uso prolongado e intenso de emisiones de espirales contra mosquitos en ratas y sus implicaciones sobre el control de la malaria

Efectos toxicológicos del uso prolongado e intenso de emisiones de espirales contra mosquitos en ratas y sus implicaciones sobre el control de la malaria. Mosquito coil is a vector control option used to prevent malaria in low income counties, while some studies have addressed this issue, additional reseach is required to increase knowledge on the adverse health effects caused by the prolonged use of coils. In this study we investigated the toxicological effects of fumes from two locally manufactured mosquito coil insecticides (with pyrethroids: transfluthrin and d-allethrin as active ingredients) on male albino rats. For this, we recorded the haematological and biochemical indices, and made histopathology and mutagenicity evaluations in rats exposed to mosquito fumes during 2, 4, 8, 12 and 16 week periods. Haematological determination was performed using automated hematology analyzer to determine White Blood Cell (WBC), Packed Cell Volume (PCV), Red Blood Cell (RBC) and Platelet (PLT) counts, while biochemical evaluations were determined using available commercial kits. Gross histopathological changes were studied for the kidney, liver and lungs in sacrificed rats. The rat sperm head abnormalities assessment was used to evaluate mutagenicity. Mosquito coil fumes produced significant increase (P<0.05) in the levels of total protein, total albumin and bilirubin, when animals were exposed from two weeks to 16 weeks with transfluthrin. Similarly, elevation in the activities of aspartate amino transferase, alanine amino transferase and alanine phosphatase, increased significantly in both insecticides. Increase in WBC, RBC and PCV were recorded for all the exposure periods, however PLT count showed no significant increase (P>0.05). Mutagenicity assessment revealed sperm abnormality was statistically significant (P<0.05) compared with the control at 8, 12 and 16 weeks post exposure to transfluthrin. Histological studies revealed severe lung damage evidenced by interstitial accumulations, pulmonary oedema and emphysema in exposed rats. Intracellular accumulations and severe sinusoidal congestion of liver cells were observed from 12 weeks exposure, indicating liver damage. Our studies indicate that mosquito coil fumes do initiate gradual damage to the host. These pathological effects must be taken into consideration by the malaria control program, particularly when regulating their long term and indoor usage.

Las espirales contra los mosquitos se utilizan en los países de bajos ingresos como una opción para prevenir la malaria controlando el vector de esta enfermedad. A pesar de que algunos estudios han abordado este tema, se requiere más investigación para incrementar el conocimiento sobre los efectos adversos en la salud, causados por el uso prolongado de las espirales. En este estudio se investigaron los efectos toxicológicos de los gases de las espirales a partir de dos insecticidas fabricados en el país (con piretroides: transflutrina y d-aletrina como ingredientes activos) en machos de ratas albinas. Para esto, se registraron los índices hematológicos y bioquímicos, y se hicieron evaluaciones histopatológicas y de mutagenicidad en ratas expuestas a los gases de las espirales durante períodos de 2, 4, 8, 12 y 16 semanas. La determinación hematológica se realizó mediante un analizador de hematología automatizado para determinar el conteo de los Glóbulos Blancos (WBC), el Hematocrito (PCV), Glóbulos Rojos (RBC) y las Plaquetas (PLT), mientras que las evaluaciones bioquímicas se determinaron utilizando kits comerciales disponibles. Los cambios histopatológicos fuertes se estudiaron en el riñón, el hígado y los pulmones de ratas sacrificadas. Las anormalidades en la cabeza de los espermatozoides de las ratas se utilizaron para evaluar la mutagenicidad. El humo de las espirales contra los mosquitos producen un aumento significativo (p<0.05) en los niveles de proteína total, albúmina total y bilirrubina, cuando los animales fueron expuestos de dos semanas a 16 semanas con transflutrina. Del mismo modo, la elevación en las actividades de aspartato amino transferasa, alanina amino transferasa y alanina fosfatasa, aumentó significativamente con ambos insecticidas. Se registro un aumento en los leucocitos, eritrocitos y el hematocrito para todos los períodos de exposición, sin embargo el recuento de las plaquetas no mostró un aumento significativo (p>0.05). Las pruebas de mutagenicidad revelaron que las anormalidades en el esperma de las ratas fue estadísticamente significativa (p>0.05) al comparar el control a las 8, 12 y 16 semanas post exposición a la transflutrina. Los estudios histológicos revelaron una serie de daños pulmonares graves en las ratas expuestas al humo de la espiral, evidenciados por la acumulación intersticial, edema pulmonar y enfisema. Las acumulaciones intracelulares y la congestión sinusoidal severa de las células del hígado se observaron a partir de las 12 semanas de exposición, lo que indica daño hepático. Nuestros estudios indican que los vapores de las espirales contra mosquitos inician el daño gradual al huésped. Estos efectos patológicos deben ser tomados en cuenta por el programa de control de la malaria, particularmente a la hora de regular su uso a largo plazo y bajo techo.

Detection of transfluthrin and metofluthrin genotoxicity in the ST cross of the Drosophila Wing Spot Test.

In this study, different concentrations of transfluthrin and metofluthrin have been assayed for genotoxicity by using the Wing Spot Test on Drosophila melanogaster. Standard cross was used in the experiment. Third-instar larvae that were trans-heterozygous for the two genetic markers mwh and flr(3) were treated at different concentrations (0.0103mgmL(-1), 0.103mgmL(-1) for transfluthrin and 6µgmL(-1), 60µgmL(-1) for metofluthrin) of the test compounds. Feeding ended with pupation of the surviving larvae and the genetic changes induced in somatic cells of the wing's imaginal discs lead to the formation of mutant clones on the wing blade. Results indicated that two experimental concentrations of transfluthrin and 60µgmL(-1) metofluthrin showed mutagenic and recombinogenic effects in both the marker-heterozygous (MH) flies and the balancer-heterozygous (BH) flies.

LC-MS/TOF, LC-MSn, on-line H/D exchange and LC-NMR studies on rosuvastatin degradation and in silico determination of toxicity of its degradation products: a comprehensive approach during drug development.

The present study dealt with the forced degradation behaviour of rosuvastatin under ICH prescribed stress conditions. The drug was found to be labile under acid hydrolytic and photolytic conditions, while it was stable to base/neutral hydrolytic, oxidative and thermal stress. In total, 11 degradation products were formed, which were separated on a C-18 column using a stability-indicating method. LC-MS analyses indicated that five degradation products had the same molecular mass as that of the drug, while the remaining six had 18 Da less than the drug. Structure elucidation of all the degradation products was executed using sophisticated and modern structural characterization tools, viz. LC-MS/TOF, LC-MS(n), on-line H/D exchange and LC-NMR. The degradation pathway and mechanisms of degradation of the drug were delineated. Additionally, in silico toxicity was predicted for all the degradation products using TOPKAT and DEREK software and compared with the drug. This study demonstrates a comprehensive approach of degradation studies during the drug development phase.

Assessment of the effects of NS11394 and L-838417, α2/3 subunit-selective GABA(A) [corrected] receptor-positive allosteric modulators, in tests for pain, anxiety, memory and motor function.

The aim of the present paper was to study the effects of GABAA receptor-positive modulators (L-838417 and NS11394) showing a preference for α2/3 subunits of the GABAA receptor, in models of pain, anxiety, learning, memory and motor function. These compounds have been suggested to have a favourable therapeutic profile over nonselective compounds such as diazepam. In this study, we tested both compounds for their effects in rat models of formalin-induced pain, spinal nerve-ligation-induced mechanical allodynia, plus maze, open field, rotarod, balance beam walking, contextual fear conditioning and Morris water maze. Both compounds exerted analgesic, but no anxiolytic effects. However, they induced motor side-effects, and learning and memory impairment at similar doses. Therefore, the anxiolytic effect and the lack of side-effects of these compounds, as described in the literature, could not be confirmed in the present study.

Effect of mosquito mats (pyrethroid-based) vapor inhalation on rat brain cytochrome P450s.

The effect of transfluthrin (TF) or D-allethrin (DA) pyrethroid (PYR) vapors, often contained as main ingredients in two commercially available mosquito repellent mats, on cytochrome P450 (CYP) enzymes of rat brain and liver was assessed. Immunodetection of CYP2E1 and CYP3A2 proteins revealed their induction in cerebrum and cerebellum, but not in liver microsomes of rats exposed by inhalation to TF or DA. This overexpression of proteins correlated with an increase of their catalytic activities. The specifically increased expression of CYP isoenzymes, due to PYR exposure in the rat brain, could perturb the normal metabolism of endogenous and xenobiotic compounds and leads to increased risks of neurotoxicity by bioactivation, lipid peroxidation and DNA damage.

Renal toxicity of lisinopril and rosuvastatin, alone and in combination, in Wistar rats.

The aim of study was to evaluate the effect of commonly used lisinopril, rosuvastatin and their combined action on site-specific nephrotoxicity in rats using clusterin and microalbumin nephrotoxic biomarkers and other related parameters using oral gavage. Rosuvastatin at 2 different doses showed increase in urinary microalbumin levels whereas lisinopril and its combination with rosuvastatin at 2 different doses did not show urinary microalbumin excretion indicating beneficial effects of lisinopril in terms of reducing microalbumin. Urinary clusterin levels significantly increased in high-dose treated animals of lisinopril and rosuvastatin. The use of lisinopril plus rosuvastatin at low dose also led to worsened renal function by raising urinary clusterin levels (217 ± 4.6 ng/ml) when compared with the control (143 ± 3.3 ng/ml). Renal histopathology showed multifocal regeneration of tubules indicating proximal tubule damaged. These results indicate that lisinopril (50 mg/kg), rosuvastatin (100 mg/kg), lisinopril+rosuvastatin (20+40 mg/kg) and lisinopril+rosuvastatin (50+100 mg/kg) showed toxicity only on proximal tubules.

The effects of oral treatment with transfluthrin on the urothelium of rats and its metabolite, tetrafluorobenzoic acid on urothelial cells in vitro.

Transfluthrin, a pyrethroid insecticide, induced urinary bladder tumors in rats but not in mice in 2-year bioassays. We investigated the urothelial effects of transfluthrin in vivo in rats and the effects of its major metabolite tetrafluorobenzoic acid (TFBA) in vitro on rat (MYP3) and human (1T1) urothelial cell lines. Rats were fed diet containing 0, 2000 or 5000 (with and without 1.25% NH(4)Cl) ppm transfluthrin for 4 weeks or 0 or 2000 ppm transfluthrin for 13 weeks. After 4 weeks, there was no evidence of hyperplasia or increased proliferation in any treatment group. After 13 weeks treatment with 2000 ppm, cytotoxicity and necrosis of the rat urothelial superficial layer were detected by scanning electron microscopy. The urinary concentration of TFBA in rats fed 2000 ppm transfluthrin was 2.94±0.67 mM. The LC(50) of TFBA was 2.25 mM for MYP3 cells and 2.43 mM for 1T1 cells. These studies support cytotoxicity and regenerative proliferation as the mechanism for induction of bladder tumors with high oral doses of transfluthrin due to metabolism of transfluthrin to the weakly cytotoxic TFBA which is excreted at high concentrations in the urine of rats administered high doses of transfluthrin (≥2000 ppm) for an extended period.

Rosuvastatin promotes osteoblast differentiation and regulates SLCO1A1 transporter gene expression in MC3T3-E1 cells.

Rosuvastatin (RSV) is a synthetic statin with favourable pharmacologic properties including minimal metabolism, hepatic selectivity and enhanced inhibition of HMG-CoA reductase. An induction of osteoblast differentiation has been reported in vitro with lipophilic statins but not with RSV, which, like pravastatin, is relatively hydrophilic compared with other statins. To mediate its action, an active transport mechanism via solute carrier (SLC) transporters from the SLC16, SLC21/SLCO and SLC22 gene family - specifically Slc16a1, Slco1a1, Slco2b1 and Slc22a8 - may be present to allow effective entry in osteoblastic cells. In this study, we demonstrate that RSV induced osteoblast differentiation, as measured by increased BMP-2 gene expression and secretion, and ALP activity in MC3T3-E1 osteoblast cells, without significantly affecting cell proliferation within the concentration range of 0.001-10 µM. Low concentrations of RSV (0.001-0.01 µM) were protective against cell death whereas higher concentrations (10-100 µM) showed cytotoxicity. Moreover, MC3T3-E1 osteoblasts expressed high levels of Slco1a1 and Slc16a1 mRNA and low levels of Slco2b1 and Slc22a8 mRNA, when compared with kidney and liver tissues from mice. Slco1a1 gene expression increased 12-fold during osteoblast differentiation and was further regulated after RSV treatment. In conclusion, as for other statins, RSV promotes osteoblast differentiation, and also, demonstrated for the first time, regulates the expression of Slco1a1, which may constitute the transport system for RSV across the cell membrane in mature osteoblasts.

Antioxidant, antinociceptive and anti-inflammatory activities of atorvastatin and rosuvastatin in various experimental models.

The present study was planned to investigate the antioxidant, antinociceptive, and anti-inflammatory activities of atorvastatin and rosuvastatin (1, 3 and 10 mg/kg, p.o.) in various animal models. The antinociceptive effect was assessed by chemically- (formalin, acetic acid) and thermally- (hot plate) induced nociception, while anti-inflammatory effect was evaluated using carrageenan-, formaldehyde-induced paw oedema and cotton pellet-induced granuloma. The effect of atorvastatin and rosuvastatin on liver antioxidant enzymes like superoxide dismutase, glutathione, LPO, CAT along with the effect on lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) was evaluated in the cotton pellet-induced granuloma model. Atorvastatin and rosuvastatin showed significant decrease (p < 0.05) in carrageenan- and formaldehyde-induced rat paw oedema and reduced granuloma formation in the cotton pellet-induced granuloma method (p < 0.01) while the levels of LDH and ALP were also significantly decreased (p < 0.05). The liver antioxidant enzyme levels were found to be restored (p < 0.05). Atorvastatin and rosuvastatin also showed antinociceptive activities (p < 0.05 and p < 0.01) in the acetic acid- and formalin-induced nociception in mice, while there was no significant activity in the hot plate method. The present findings suggest that atorvastatin and rosuvastatin possess dose-dependent antioxidant, analgesic, and anti-inflammatory activities.

Comparison of the effects of the synthetic pyrethroid Metofluthrin and phenobarbital on CYP2B form induction and replicative DNA synthesis in cultured rat and human hepatocytes.

High doses of Metofluthrin (MTF) have been shown to produce liver tumours in rats by a mode of action (MOA) involving activation of the constitutive androstane receptor leading to liver hypertrophy, induction of cytochrome P450 (CYP) forms and increased cell proliferation. The aim of this study was to compare the effects of MTF with those of the known rodent liver tumour promoter phenobarbital (PB) on the induction CYP2B forms and replicative DNA synthesis in cultured rat and human hepatocytes. Treatment with 50 microM MTF and 50 microM PB for 72 h increased CYP2B1 mRNA levels in male Wistar rat hepatocytes and CYP2B6 mRNA levels in human hepatocytes. Replicative DNA synthesis was determined by incorporation of 5-bromo-2'-deoxyuridine over the last 24 h of a 48 h treatment period. Treatment with 10-1000 microM MTF and 100-500 microM PB resulted in significant increases in replicative DNA synthesis in rat hepatocytes. While replicative DNA synthesis was increased in human hepatocytes treated with 5-50 ng/ml epidermal growth factor or 5-100 ng/ml hepatocyte growth factor, treatment with MTF and PB had no effect. These results demonstrate that while both MTF and PB induce CYP2B forms in both species, MTF and PB only induced replicative DNA synthesis in rat and not in human hepatocytes. These results provide further evidence that the MOA for MTF-induced rat liver tumour formation is similar to that of PB and some other non-genotoxic CYP2B form inducers and that the key event of increased cell proliferation would not occur in human liver.

Statin-induced myopathy in the rat: relationship between systemic exposure, muscle exposure and myopathy.

Rare instances of myopathy are associated with all statins, but cerivastatin was withdrawn from clinical use due to a greater incidence of myopathy. The mechanism of statin-induced myopathy with respect to tissue disposition was investigated by measuring the systemic, hepatic, and skeletal muscle exposure of cerivastatin, rosuvastatin, and simvastatin in rats before and after muscle damage. The development of myopathy was not associated with the accumulation of statins in skeletal muscle. For each statin exposure was equivalent in muscles irrespective of their fibre-type sensitivity to myopathy. The low amount of each statin in skeletal muscle relative to the liver does not support a significant role for transporters in the disposition of statins in skeletal muscle. Finally, the concentration of cerivastatin necessary to cause necrosis in skeletal muscle was considerably lower than rosuvastatin or simvastatin, supporting the concept cerivastatin is intrinsically more myotoxic than other statins.

Mode of action analysis for the synthetic pyrethroid metofluthrin-induced rat liver tumors: evidence for hepatic CYP2B induction and hepatocyte proliferation.

Two-year treatment with high doses of Metofluthrin produced hepatocellular tumors in both sexes of Wistar rats. To understand the mode of action (MOA) by which the tumors are produced, a series of studies examined the effects of Metofluthrin on hepatic microsomal cytochrome P450 (CYP) content, hepatocellular proliferation, hepatic gap junctional intercellular communication (GJIC), oxidative stress and apoptosis was conducted after one or two weeks of treatment. The global gene expression profile indicated that most genes with upregulated expression with Metofluthrin were metabolic enzymes that were also upregulated with phenobarbital. Metofluthrin induced CYP2B and increased liver weights associated with centrilobular hepatocyte hypertrophy (increased smooth endoplasmic reticulum [SER]), and induction of increased hepatocellular DNA replication. CYP2B1 mRNA induction by Metofluthrin was not observed in CAR knockdown rat hepatocytes using the RNA interference technique, demonstrating that Metofluthrin induces CYP2B1 through CAR activation. Metofluthrin also suppressed hepatic GJIC and induced oxidative stress and increased antioxidant enzymes, but showed no alteration in apoptosis. The above parameters related to the key events in Metofluthrin-induced liver tumors were observed at or below tumorigenic dose levels. All of these effects were reversible upon cessation of treatment. Metofluthrin did not cause cytotoxicity or peroxisome proliferation. Thus, it is highly likely that the MOA for Metofluthrin-induced liver tumors in rats is through CYP induction and increased hepatocyte proliferation, similar to that seen for phenobarbital. Based on analysis with the International Life Sciences Institute/Risk Science Institute MOA framework, it is reasonable to conclude that Metofluthrin will not have any hepatocarcinogenic activity in humans, at least at expected levels of exposure.