Cyto-genotoxicity and oxidative stress induced by zinc oxide nanoparticle in human lymphocyte cells in vitro and Swiss albino male mice in vivo

ZnO-np has immense potential and application in cosmetic and health care sectors. Hence it was imperative to assess the toxicity/safety of these nanoparticles. In this study, we have evaluated the effects of ZnO-np in human peripheral blood mononuclear cells (PBMCs) in vitro and in Swiss albino male mice in vivo for cyto-genotoxicity and oxidative damage. In vitro results showed that ZnO-nps were weakly genotoxic, induced significant decrease in mitochondrial membrane potential and was capable of ROS generation, leading to apoptosis. In bone marrow cells in vivo, reduction of mitochondrial membrane potential (MMP), increased oxidative stress and G0/G1 cell cycle arrest was observed along with chromosome aberrations and micronuclei formation. In liver cells DNA damage and induction of oxidative stress with concurrent decrease in inhibition of antioxidant enzymes were noted. These in vitro and in vivo results demonstrated that ZnO-np induced genotoxic response and ROS production leading to apoptotic cell death and established a good co-relation between the two biological systems. More importantly, the results stress on the need of multiple endpoint assay-approaches, with an in vitro-in vivo study design to assess nanoparticle toxicology.     

叶黄素预处理对顺铂损伤大鼠肝超微结构的影响

目的：观察叶黄素（LU）对顺铂（CP）损伤大鼠肝组织超微结构的影响。方法：将24只雌性SD大鼠随机分为生理盐水组（NS组）,化疗模型组（CP组）,和LU干预组（LU+CP组）。NS组及CP组大鼠灌胃玉米油,LU+CP组大鼠按40mg/kg 灌胃LU玉米油溶液。灌胃7d后,CP组和LU+CP组腹腔注射CP 5mg/kg,NS组腹腔注射等量生理盐水。注射4d后,剖取肝脏,在光镜、透射电镜下观察大鼠肝组织形态结构改变。结果：应用LU可减轻CP所致的肝细胞质空泡化,肝门管区纤维化等改变,同时可减轻CP引起的线粒体嵴结构断裂或消失、内质网呈片层状,及染色质边集于核膜下等超微结构改变。结论：预防性喂饲LU可对CP损伤大鼠肝脏病理及超微结构可产生一定的保护作用。     

Breast cancer resistance protein (BCRP/ABCG2) localises to the nucleus in glioblastoma multiforme cells

1. The breast cancer resistance protein (BCRP), an ATP binding cassette (ABC) efflux transporter, plays a role in multiple drug resistance (MDR). Previous studies of the subcellular location of the ABC transporter P-glycoprotein indicated that this protein is expressed in nuclear membranes. This study examines the nuclear distribution of BCRP in seven human-derived glioblastoma (GBM) and astrocytoma cell lines.

2. BCRP expression was observed in the nuclear extracts of 6/7 cell lines. Using the GBM LN229 cell line as a model, nuclear BCRP protein was detected by immunoblotting and confocal laser microscopy. Importantly, nuclear BCRP staining was found in a subpopulation of tumour cells in a human brain GBM biopsy.

3. Mitoxantrone cytotoxicity in the LN229 cell line was determined with and without the BCRP inhibitor fumitremorgin C (FTC) and after downregulation of BCRP with small interfering RNA (siRNA). FTC inhibition of BCRP increased mitoxantrone cytotoxicity with a ~7-fold reduction in the IC₅₀ and this effect was further potentiated in the siRNA -treated cells.

4. In conclusion, BCRP is expressed in the nuclear extracts of select GBM and astrocytoma cell lines and in a human GBM tumour biopsy. Its presence in the nucleus of cancer cells suggests new role for BCRP in MDR.

     

Levosimendan and its metabolite OR-1896 elicit KATP channel-dependent dilation in resistance arteries in vivo

BackgroundLevosimendan and its long-lived metabolite OR-1896 produce vasodilation in different types of vessels by activating ATP-sensitive (K_ATP) and other potassium channels.MethodsIn the present study we applied intravital videomicroscopy to investigate the in situ effects of levosimendan and OR-1896 on the diameters of real resistance arterioles (rat cremaster muscle arterioles with diameters of ~ 20 μm).ResultsLevosimendan and OR-1896 induced concentration-dependent (1 nM – 100 μM) dilations to similar extents in these arterioles (maximal dilation from 23 ± 2 to 33 ± 2 μm and from 22 ± 1 to 32 ± 1 μm, respectively). The arteriolar dilations induced by the selective K_ATP channel opener pinacidil (1 nM – 10 μM) (maximal dilation from 22 ± 4 μm to 35 ± 3 μm) were diminished in the presence of the selective K_ATP channel blocker – glibenclamide (5 μM) (maximal diameter attained: 22 ± 1 μm). Glibenclamide also counteracted the maximal dilations in response to levosimendan or OR-1896 (to 23 ± 3 μm or 22 ± 5 μm, respectively).ConclusionsIn conclusion, this is the first demonstration that levosimendan and OR-1896 elicit arteriolar dilation in vivo, via activation of K_ATP channels in real resistance vessels in the rat.     

Diuron metabolites and urothelial cytotoxicity: In vivo,in vitro and molecular approaches

Diuron is carcinogenic to the rat urinary bladder at high dietary levels. The proposed mode of action (MOA) for diuron is urothelial cytotoxicity and necrosis followed by regenerative urothelial hyperplasia. Diuron-induced urothelial cytotoxicity is not due to urinary solids. Diuron is extensively metabolized, and in rats, N-(3,4-dichlorophenyl)urea (DCPU) and 4,5-dichloro-2-hydroxyphenyl urea (2-OH-DCPU) were the predominant urinary metabolites; lesser metabolites included N-(3,4-dichlorophenyl)-3-methylurea (DCPMU) and trace levels of 3,4-dichloroaniline (DCA). In humans, DCPMU and DCPU have been found in the urine after a case of product abuse. To aid in elucidating the MOA of diuron and to evaluate the metabolites that are responsible for the diuron toxicity in the bladder epithelium, we investigated the urinary concentrations of metabolites in male Wistar rats treated with 2500 ppm of diuron, the urothelial cytotoxicity in vitro of the metabolites and their gene expression profiles. DCPU was found in rat urine at concentrations substantially greater than the in vitro IC50 and induced more gene expression alterations than the other metabolites tested. 2-OH-DCPU was present in urine at a concentration approximately half of the in vitro IC50, whereas DCPMU and DCA were present in urine at concentrations well below the IC50. For the diuron-induced MOA for the rat bladder, we suggest that DCPU is the primary metabolite responsible for the urothelial cytotoxicity with some contribution also by 2-OH-DCPU. This study supports a MOA for diuron-induced bladder effects in rats consisting of metabolism to DCPU (and 2-OH-DCPU to a lesser extent), concentration and excretion in urine, urothelial cytotoxicity, and regenerative proliferation.     

Commercial Carlinae radix herbal drug: Botanical identity,chemical composition and antimicrobial properties

Context: Carlinae radix is an herbal drug, commonly used by the locals in southeastern Serbia for the treatment of respiratory and urogenital diseases and, externally, for various skin conditions. There still seems to be no detailed studies correlating the chemical composition of this drug and its ethnopharmacological uses.

Objective: Chemical composition, antimicrobial activity and mode of action of C. radix essential oil, isolated from commercial samples (confirmation of whose true biological identity was also the aim of this work) were analyzed. Antimicrobial potential of decoctions (extracts prepared by boiling plant material in a given solvent), used in ethnomedicine preferentially to the pure essential oil, was also investigated.

Materials and methods: The essential oil obtained by hydrodistillation was screened for antimicrobial activity by disc diffusion and broth microdilution methods. Effects of the oil on the growth of Staphylococcus aureus cells were investigated using turbidimetric measurements and visualized using scanning electron microscopy. Analyses of the chemical composition of the oils were done using gas chromatography and gas chromatography/mass spectrometry.

Results and discussion: Both the essential oil and the decocts exhibited a very high antimicrobial activity against all tested strains, with S. aureus as the most sensitive one [e.g., for the oil sample the values for minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were 0.02, 0.04 µL/mL, respectively]. Growth curves of S. aureus demonstrated a significant decrease in turbidity (for the MIC concentration this amounted to ca. 70%) showing a concentration-dependent lysis of the cells, confirmed by scanning electron microscopy. Chemical composition, anatomical and morphological features of the sample pointed to Carlina acanthifolia L. (Asteraceae) instead of Carlina acaulis L. (Asteraceae).

Conclusion: The results showed significant antimicrobial effect of the essential oil and the decoctions and support the use of this plant in ethnomedicine for the treatment of various human infections, especially those caused by S. aureus. Adulteration of the drug would not cause significant differences in its biological activity, since chemical composition of the sample showed high similarity with those containing C. acaulis roots.     

Tuberculosis diagnostics in Fiji: how reliable is culture?

Settings: Acid-fast bacilli (AFB) smear microscopy and Mycobacterium tuberculosis culture are the first-line diagnostic tests for tuberculosis (TB). The contamination of TB cultures significantly reduces the reliability of TB diagnosis.Objective: To investigate factors associated with TB culture contamination in Fiji, and the relative diagnostic performance of culture compared to microscopy.Design: All tests performed at the Daulakao Mycobacterium Reference Laboratory (DMRL) in Fiji from 2010 to 2012 were reviewed. Study variables included AFB smear and TB culture results, age and type of specimen, referring TB testing centre and patient age.Results: Of 5708 specimens reviewed, 70% had both AFB smear and culture results recorded; 421 specimens were contaminated; 2.7% of specimens were either degraded or had no result recorded. There was moderate agreement (κ = 0.577) between the two tests. Culture was more likely to be positive at higher AFB smear scores. Culture contamination was associated with distance from the DMRL, sample age and operator-associated factors.Conclusion: Increases in the speed of referral from TB testing centres or the addition of preservatives to sputum specimens may results in less culture contamination. The planned introduction of liquid culture techniques in combination with culture on Ogawa media is likely to increase the sensitivity of TB diagnosis in Fiji.     

Biochemical,histopathological, and transmission electron microscopic ultrastructural changes in mice after exposure to silver nanoparticles

Four‐week‐old mice, weighing about 25–35 g were divided into five groups (8 mice in each group): vehicle control, low‐ (0.5 g/kg), middle‐ (1 g/kg), high‐ (3 g/kg), and exceptionally high‐dose (5 g/kg). After first and second weeks of intraperitoneal exposure to AgNPs, biochemical, histopathological, and electron microscopic ultrastructural changes were investigated. No significant changes were observed in SGOT and ALP levels after first week of exposure, while the level of SGPT significantly increased (p < 0.05) in 2nd week treated mice, indicating that inflammatory of liver might be induced by high‐dose (3 and 5 g/kg) of AgNPs. No obvious changes were observed for UA and BUN in all groups of treated mice. However, significant (p < 0.05) decrease in CR level was noticed in all groups of treated mice only at high‐dose (3 and 5 g/kg). No remarkable changes in lipid profile were observed. Light microscopic histopathological investigation shows that first week treatment had not perceptible effect on the cytoarchitecture on liver, kidney, and spleen; while, second week treatment had only sporadic mild effects on these organs. However, no ultrastructural electron microscopic changes were observed in liver, kidney, and spleen of mice treated with 0.5, 1, and 3 g/kg of AgNPs when sacrificed on first and second week; while, exceptionally high‐dose (5 g/kg) of AgNPs resulted in slight nuclear chromatin condensation and irregularities in nuclear membrane. The results suggested that AgNPs could be well tolerated in mice when given intraperitoneally and no death has been found during the experiment in any groups of treated mice. Interestingly, significant (<0.05) decrease in glucose levels in all experiment group is suggestive of curious hypoglycemic role of AgNPs warranting further study to explore its possible therapeutic potential in hyperglycemic conditions as well as its mechanism of action at molecular level. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 945–956, 2016.     

β‐lactoglobulin–pectin Nanoparticle‐based Oral Drug Delivery System for Potential Treatment of Colon Cancer

Colon cancer is one of the most common internal malignancies, and conventional chemotherapy is not effective in its treatment. Nanoparticles hold tremendous potential as an effective drug delivery system. The physicochemical properties of β‐lactoglobulin, the main whey protein of cow's milk, such as its stability at low pH, its resistance to gastric protease, and its ability to bind hydrophobic ligands, give it potential for transporting drugs specifically for colon cancer. In the present research, β‐lactoglobulin–pectin nanoparticles were designed to transfer a newly synthesized, anticancer platinum complex (bipyridine ethyl dithiocarbamate Pt(II) nitrate), to the colon. The effects of multiple factors on the size and the colloidal stability of the nanoparticles were studied using dynamic light scattering and scanning electron microscopy techniques. Results showed that the best particle size and highest colloidal stability were obtained in phosphate buffer, pH 4.5, with 0.5 mg/mL β‐lactoglobulin and 0.025–0.05wt% pectin. The drug release profile in simulated gastrointestinal conditions demonstrated that β‐lactoglobulin with a secondary coating is stable in acidic conditions but is able to release its cargo at pH 7. Hence, these nanoparticles have potential to serve as novel and effective vehicles for oral drug delivery preparations.