Low-dose exposure to malathion and radiation results in the dysregulation of multiple neuronal processes, inducing neurotoxicity and neurodegeneration in mouse.

Neurodegenerative disorders are a debilitating and persistent threat to the global elderly population, carrying grim outcomes. Their genesis is often multifactorial, with a history of prior exposure to xenobiotics such as pesticides, heavy metals, enviornmental pollutants, ionizing radiation etc,. A holistic molecular insight into their mechanistic induction upon single or combinatorial exposure to different toxicants is still unclear. In the present study, one-month-old C57BL/6 male mice were administered orally with malathion (50 mg/kg body wt. for 14 days) and single whole-body radiation (0.5 Gy) on the 8th day. Post-treatment, behavioural assays for exploratory behaviour, memory, and learning were performed. After sacrifice, brains were collected for histology, biochemical assays, and transcriptomic analysis. Transcriptomic analysis revealed several altered processes like synaptic transmission and plasticity, neuronal survival, proliferation, and death. Signalling pathways like MAPK, PI3K-Akt, Apelin, NF-κB, cAMP, Notch etc., and pathways related to neurodegenerative diseases were altered. Increased astrogliosis was observed in the radiation and coexposure groups, with significant neuronal cell death and a reduction in the expression of NeuN. Sholl analysis, dendritic arborization and spine density studies revealed decreased total apical neuronal path length and dendritic spine density. Reduced levels of the antioxidants GST and GSH and acetylcholinesterase enzyme activity were also detected. However, no changes were seen in exploratory behaviour or learning and memory post-treatment. Thus, explicating the molecular mechanisms behind malathion and radiation can provide novel insights into external factor-driven neurotoxicity and neurodegenerative pathogenesis.

Biological and chemical properties of 2-in-1 calcium-chelating and antibacterial root canal irrigants.

OBJECTIVES: To evaluate the capacity of canal wall smear layer removal, precipitation caused by irrigant interaction, antibacterial activity and cytotoxicity of three 2-in-1 root canal irrigating solutions. METHODS: Forty single-rooted teeth were mechanically instrumented and irrigated with QMix, SmearOFF, Irritrol or 0.9% saline. Each tooth was evaluated for smear layer removal using scanning electron microscopy. Precipitation after interaction of the irrigating solutions with sodium hypochlorite (NaOCl) was evaluated with 1H nuclear magnetic resonance and mass spectroscopy. Confocal laser scanning microscopy was used to evaluate the antimicrobial activity of the irrigants against Enterococcus faecalis biofilms. Neutral red and clonogenic assays were performed on Chinese hamster V79 cells to evaluate the short-term and long-term cytotoxicity of the irrigants. RESULTS: There was no significant difference between QMix and SmearOFF in eliminating smear layers from the coronal-third and middle-third of the canal spaces. In the apical-third, SmearOFF removed smear layers effectively. Irritrol incompletely removed smear layers from all the canal-thirds. When mixed with NaOCl, precipitation was evident only with Irritrol. QMix demonstrated a higher E. faecalis cell death percentage and a smaller biovolume. SmearOFF exhibited a larger decrease in biovolume compared with Irritrol, although Irritrol had a higher death percentage. Irritrol was more cytotoxic than the other irrigants on a short-term interval. In terms of long-term cytotoxicity, both Irritrol and QMix were cytotoxic. CONCLUSION: QMix and SmearOFF performed better in smear layer removal and antimicrobial activity. QMix and Irritrol were cytotoxic when compared to SmearOFF. Irritrol was associated with precipitation after interacting with NaOCl. CLINICAL SIGNIFICANCE: Evaluation of the smear layer removal capability, antibacterial activity and cytotoxicity of 2-in-1 root canal irrigants is necessary to ensure that they are safe to use during root canal treatment.

Development of Lipidic Nanoplatform for Intra-Oral Delivery of Chlorhexidine: Characterization, Biocompatibility, and Assessment of Depth of Penetration in Extracted Human Teeth.

Microorganisms are the major cause for the failure of root canal treatment, due to the penetration ability within the root anatomy. However, irrigation regimens have at times failed due to the biofilm mode of bacterial growth. Liposomes are vesicular structures of the phospholipids which might help in better penetration efficiency into dentinal tubules and in increasing the antibacterial efficacy. Methods: In the present work, chlorhexidine liposomes were formulated. Liposomal chlorhexidine was characterized by size, zeta potential, and cryo-electron microscope (Cryo-EM). Twenty-one single-rooted premolars were extracted and irrigated with liposomal chlorhexidine and 2% chlorhexidine solution to evaluate the depth of penetration. In vitro cytotoxicity study was performed for liposomal chlorhexidine on the L929 mouse fibroblast cell line. Results: The average particle size of liposomes ranged from 48 ± 4.52 nm to 223 ± 3.63 nm with a polydispersity index value of <0.4. Cryo-EM microscopic images showed spherical vesicular structures. Depth of penetration of liposomal chlorhexidine was higher in the coronal, middle, and apical thirds of roots compared with plain chlorhexidine in human extracted teeth when observed under the confocal laser scanning microscope. The pure drug exhibited a cytotoxic concentration at which 50% of the cells are dead after a drug exposure (IC50) value of 12.32 ± 3.65 µg/mL and 29.04 ± 2.14 µg/mL (on L929 and 3T3 cells, respectively) and liposomal chlorhexidine exhibited an IC50 value of 37.9 ± 1.05 µg/mL and 85.24 ± 3.22 µg/mL (on L929 and 3T3 cells, respectively). Discussion: Antimicrobial analysis showed a decrease in colony counts of bacteria when treated with liposomal chlorhexidine compared with 2% chlorhexidine solution. Nano-liposomal novel chlorhexidine was less cytotoxic when treated on mouse fibroblast L929 cells and more effective as an antimicrobial agent along with higher penetration ability.

Photobiomodulation invigorating collagen deposition, proliferating cell nuclear antigen and Ki67 expression during dermal wound repair in mice.

The present investigation focuses on understanding the role of photobiomodulation in enhancing tissue proliferation. Circular excision wounds of diameter 1.5 cm were created on Swiss albino mice and treated immediately with 2 J/cm2 and 10 J/cm2 single exposures of the Helium-Neon laser along with sham-irradiated controls. During different days of healing progression (day 5, day 10, and day 15), the tissue samples upon euthanization of the animals were taken for assessing collagen deposition by Picrosirius red staining and cell proliferation (day 10) by proliferating cell nuclear antigen (PCNA) and Ki67. The positive influence of red light on collagen synthesis was found to be statistically significant on day 10 (P < 0.01) and day 15 (P < 0.05) post-wounding when compared to sham irradiation, as evident from the image analysis of collagen birefringence. Furthermore, a significant rise in PCNA (P < 0.01) and Ki67 (P < 0.05) expression was also recorded in animals exposed to 2 J/cm2 when compared to sham irradiation and (P < 0.01) compared to the 10 J/cm2 treated group as evidenced by the microscopy study. The findings of the current investigation have distinctly exhibited the assenting influence of red laser light on excisional wound healing in Swiss albino mice by augmenting cell proliferation and collagen deposition.

Full Factorial Design for Development and Validation of a Stability-Indicating RP-HPLC Method for the Estimation of Timolol Maleate in Surfactant-Based Elastic Nano-Vesicular Systems.

A novel isocratic stability-indicating chromatographic method was developed, optimized and validated using Design-Expert® following ICH guidelines for the quantification of Timolol maleate (TM). The intrinsic stability of TM was assessed by force degradation studies, which concluded no extensive degradation except under alkaline and oxidative conditions. TM was quantified accurately in the surfactant-based elastic vesicular system by separating it on Hypersil BDS C8 column using triethylamine in H2O (0.15%v/v; pH 3.0) and acetonitrile (ACN; 65:35%v/v). The influence of variable factors like mobile phase pH, injection volume (µL), flow rate (mL/min) and ACN content (%) on method responses were assessed using a full factorial design. The method was linear between 0.05 and 10 µg/mL with an R2 value of 0.9993. Limit of detection and limit of quantification were found to be 0.90 and 27.2 ng/mL. The method was specific, with recovery in plain drug solution of 89-92% and elastic nanovesicles of 90-93%. The experimental model was significant (P < 0.0001) as indicated by deliberate changes in the method analyzed through analysis of variance. The total drug content in elastic nanovesicles was estimated to be 9.53 ± 0.01 mg/20-mL dispersion and entrapment efficiency was 44.52 ± 0.73%. The developed method was rapid, economic and precise for the quantification of TM in bulk and vesicular system.

Mangiferin, a naturally occurring polyphenol, mitigates oxidative stress induced premature senescence in human dermal fibroblast cells.

Chronic oxidative stress has been associated with several human ailments including the condition of aging. Extensive studies have shown the causal relationship between oxidative stress, aging, and cellular senescence. In this regard, forestalling or preventing senescence could delay the aging process as well as act as an intervention against premature aging. Hence, in the present study, we investigated the anti-senescence potential of Mangiferin (MGN) against Hydrogen peroxide (H2O2) induced premature senescence using human dermal fibroblast cells. Early passage human dermal fibroblasts cells were exposed to H2O2 (10 µM) for 15 days. In order to assess the anti-senescence property of MGN, cells were preconditioned with MGN (10 µM / 50 µM; 2 h) followed by addition of H2O2 (10 µM). H2O2 mediated induction of premature senescence was accompanied by elevated ROS, lowering of mitochondrial mass and membrane potential, changes in ATP content along with G0/G1 arrest and SA-ß-gal expression. While, conditioning the cells with MGN lowered oxidative burden, stabilized mitochondrial membrane potential / mass and protected the cells against cell cycle arrest, ultimately rendering protection against premature senescence. The present findings showed that MGN might act as a potential cytoprotective nutraceutical that can prolong the onset of chronic oxidative stress mediated premature senescence.

Biomimetic nanoarchitecturing: A disguised attack on cancer cells.

With the changing face of healthcare, there is a demand for drug delivery systems that have increased efficacy and biocompatibility. Nanotechnology derived drug carrier systems were found to be ideal candidates to meet these demands. Among the vast number of nanosized delivery systems, biomimetic nanoparticles have been researched at length. These nanoparticles mimic cellular functions and are highly biocompatible. They are also able to avoid clearance by the reticuloendothelial system which increases the time spent by them in the systemic circulation. Additionally, their low immunogenicity and targeting ability increase their significance as drug carriers. Based on their core material we have summarized them as biomimetic inorganic nanoparticles, biomimetic polymeric nanoparticles, and biomimetic lipid nanoparticles. The core then may be coated using membranes derived from erythrocytes, cancer cells, leukocytes, stem cells, and other membranes to endow them with biomimetic properties. They can be used for personalized therapy and diagnosis of a large number of diseases, primarily cancer. This review summarizes the various therapeutic approaches using biomimetic nanoparticles along with their applications in the field of cancer imaging, nucleic acid therapy and theranostic properties. A brief overview about toxicity concerns related to these nanoconstructs has been added to provide knowledge about biocompatibility of such nanoparticles.

Small interfering RNAs (siRNAs) based gene silencing strategies for the treatment of glaucoma: Recent advancements and future perspectives.

RNA-interference-based mechanisms, especially the use of small interfering RNAs (siRNAs), have been under investigation for the treatment of several ailments and have shown promising results for ocular diseases including glaucoma. The eye, being a confined compartment, serves as a good target for the delivery of siRNAs. This review focuses on siRNA-based strategies for gene silencing to treat glaucoma. We have discussed the ocular structures and barriers to gene therapy (tear film, corneal, conjunctival, vitreous, and blood ocular barriers), methods of administration for ocular gene delivery (topical instillation, periocular, intracameral, intravitreal, subretinal, and suprachoroidal routes) and various viral and non-viral vectors in siRNA-based therapy for glaucoma. The components and mechanism of siRNA-based gene silencing have been mentioned briefly followed by the basic strategies and challenges faced during siRNA therapeutics development. We have emphasized different therapeutic targets for glaucoma which have been under research by scientists and the current siRNA-based drugs used in glaucoma treatment. We also mention briefly strategies for siRNA-based treatment after glaucoma surgery.

Neuroprotection: A versatile approach to combat glaucoma.

In most retinal diseases, neuronal loss is the main cause of vision loss. Neuroprotection is the alteration of neurons and/or their environment to encourage the survival and function of the neurons, especially in environments that are deleterious to the neuronal health. The area of neuroprotection progresses with a therapeutically-based hope of improving vision and clinical outcomes for patients through the developments in neurotrophic therapy, antioxidative therapy, anti-excitotoxic, anti-ischemic, anti-inflammatory, and anti-apoptotic care. In this review, we summarize the various neuroprotection strategies for the treatment of glaucoma, genetics of glaucoma and the role of various nanoplatforms in the treatment of glaucoma.

Systemic Toxicity and Teratogenicity of Copper Oxide Nanoparticles and Copper Sulfate.

Acceleration in development of metallic nanoparticles for their utility in medical and technological applications due to their unique physicochemical properties has concurrently raised a matter of concern due to their potential toxicity. Of the enormous metallic nanostructures, copper oxide nanoparticles (CuONPs) having optical and electrochemical properties are scrutinized for theranostic applications. Therefore, their safety profile is of a major concern in optimizing a safe dose for its clinical utility. Considering the potency of CuONPs in epitomizing toxicity, we report a dose and time dependent acute, systemic and transgenerational toxicity profile of CuONPs in comparison to the bulk copper as copper sulfate (CuSO4). Acute toxic dose (LD50(14)) of CuONPs (400 mg/kg · b · wt) was found to be three fold higher that of CuSO4(100 mg/kg · b · wt). Comparative steady state evaluation showed that CuONPs (≥5 mg/kg · b · wt.) induce greater dose and time dependent oxidative stress by increase in protein carbonylation and decreased glutathione levels in comparison to the bulk CuSO4. Furthermore, CuONPs were found to disrupt blood brain barrier (BBB) and sneak in to the brain which was quantified by atomic absorption spectroscopy (AAS) and also coax toxicity in liver, kidney and spleen, ascertained by histopathological findings (at ≥5 mg/kg · b · wt.). Considering transgenerational toxicity, CuONPs in comparison to CuSO4 severely affected sperm count and morphology in male animals, though not much teratological effects were observed, except certain extent of embryo resorption. The present study highlights a complete toxicity profile of CuONPs, giving forethought for considering them for clinical applications.

Laser-induced autofluorescence-based objective evaluation of burn tissue repair in mice.

Management of burn injuries are a growing concern, especially in determining the progression of healing. Several techniques are being practiced in clinics and have been considered all-time standard approaches to determine pre- and post-treatment outcomes of a healthy healing. However, these kinds of methods involve repeated biopsies and thereby hindering tissue repair. In view of this, our perspective was to develop a non-invasive tool in an attempt to provide a solution to determine the progression of healing, in vivo. Hence, the present study was designed to investigate the ability of laser-induced fluorescence (LIF) to monitor the variations in collagen intensity at various time points (0, 2, 6, 12, 18, 24, and 30 days) during burn tissue repair in mice, post low-power laser therapy (LPLT). The spectral findings demonstrated a significant change in collagen intensity as observed on day 24 (p < 0.05) and 30 (p < 0.01), when treated with LPLT (830 nm 3 J/cm2) as compared to untreated control. From the observation, it was evident that the LIF could objectively monitor the progression of burn tissue repair in vivo.

A polymeric temozolomide nanocomposite against orthotopic glioblastoma xenograft: tumor-specific homing directed by nestin.

The development of effective therapeutic strategies for glioblastoma faces challenges such as modulating the blood brain barrier (BBB) for drug influx and selectively targeting tumor cells. Nanocarrier drug delivery strategies are functionalized to enhance vascular permeability. We engineered superparamagnetic iron oxide nanoparticle (SPION) based polymeric nanocomposites (84.37 ± 12.37 nm / 101.56 ± 7.42 nm) embedding temozolomide (TMZ) targeted against glioblastoma by tagging an antibody against nestin, a stem cell marker, and transferrin / polysorbate-80 to permeate the BBB. The targeting and therapeutic efficacy of the nanocomposite resulted in enhanced permeability across the BBB in an orthotopic glioblastoma xenograft model. Sustained release of TMZ from the nanocomposite contributed to enhanced tumor cell death while sparing normal brain cells as evidenced through micro SPECT/CT analysis. The functionalized nanocomposites showed significant reductions in tumor volume compared to pure TMZ, as substantiated by reduced proliferation markers such as proliferating cell nuclear antigen (PCNA) and Ki-67. We report here a novel targeted TMZ delivery strategy using a potent homing moiety, nestin, tagged to a polymeric nanocomposite to target glioblastoma. In addition to tumor targeting, this study constitutes a broad horizon for enhanced therapeutic efficacy with further scope for capitalizing on the magnetic properties of SPION for targeted killing of cancer cells while sparing normal tissues.

Naringin abates adverse effects of cadmium-mediated hepatotoxicity: An experimental study using HepG2 cells.

This study investigated the protective potential of Naringin (NIN) against cadmium chloride (CdCl2 ) mediated hepatotoxicity using human hepatocellular carcinoma (HepG2) cells. An optimal concentration of NIN (5 µM) was potent enough to confer cytoprotection against CdCl2 (50 µM) as was observed by MTT assay. Preconditioning with NIN maintained redox homeostasis, mitochondrial membrane potential, and reduced apoptosis as marked by decrease in the percentage sub-G0 /G1 and Annexin V-FITC/propidium iodide positive cells (apoptotic). NIN pretreatment maintained the levels of protein thiol along with endogenous activities of Superoxide dismutase, Glutathione S-transferase, and Catalase and lowered lipid peroxidation. Decreased Bax/Bcl2 ratio along with reduced Caspase 3 cleavage and Cytochrome c release indicated that NIN conditioning blocked mitochondrial-mediated apoptosis. Increased Nrf2 and metallothionein (MT) acted as adaptive response in the presence of cadmium. Thus, the protective mechanism of NIN is attributed to its antioxidant potential which aids in redox homeostasis and prevents CdCl2 mediated cytotoxicity.

Identification of protein secondary structures by laser induced autofluorescence: A study of urea and GnHCl induced protein denaturation.

In the present study an attempt has been made to interrogate the bulk secondary structures of some selected proteins (BSA, HSA, lysozyme, trypsin and ribonuclease A) under urea and GnHCl denaturation using laser induced autofluorescence. The proteins were treated with different concentrations of urea (3M, 6M, 9M) and GnHCl (2M, 4M, 6M) and the corresponding steady state autofluorescence spectra were recorded at 281nm pulsed laser excitations. The recorded fluorescence spectra of proteins were then interpreted based on the existing PDB structures of the proteins and the Trp solvent accessibility (calculated using "Scratch protein predictor" at 30% threshold). Further, the influence of rigidity and conformation of the indole ring (caused by protein secondary structures) on the intrinsic fluorescence properties of proteins were also evaluated using fluorescence of ANS-HSA complexes, CD spectroscopy as well as with trypsin digestion experiments. The outcomes obtained clearly demonstrated GnHCl preferably disrupt helix as compared to the beta ß-sheets whereas, urea found was more effective in disrupting ß-sheets as compared to the helices. The other way round the proteins which have shown detectable change in the intrinsic fluorescence at lower concentrations of GnHCl were rich in helices whereas, the proteins which showed detectable change in the intrinsic fluorescence at lower concentrations of urea were rich in ß-sheets. Since high salt concentrations like GnHCl and urea interfere in the secondary structure analysis by circular dichroism Spectrometry, the present method of analyzing secondary structures using laser induced autofluorescence will be highly advantageous over existing tools for the same.

Photo-biomodulatory response of low-power laser irradiation on burn tissue repair in mice.

The present work reports the photo-biomodulatory effect of red (632.8 nm) and near infrared (785 and 830 nm) lasers on burn injury in Swiss albino mice. Animals were induced with a 15-mm full thickness burn injury and irradiated with various fluences (1, 2, 3, 4, and 6 J/cm2) of each laser wavelength under study having a constant fluence rate (8.49 mW/cm2). The size of the injury following treatment was monitored by capturing the wound images at regular time intervals until complete healing. Morphometric assessment indicated that the group treated with 3-J/cm2 fluence of 830 nm had a profound effect on healing as compared to untreated controls and various fluences of other wavelengths under study. Histopathological assessment of wound repair on treatment with an optimum fluence (3 J/cm2) of 830 nm performed on days 2, 6, 12, and 18 post-wounding resulted in enhanced wound repair with migration of fibroblasts, deposition of collagen, and neovascularization as compared to untreated controls. The findings of the present study have clearly demonstrated that a single exposure of 3-J/cm2 fluence at 830-nm enhanced burn wound healing progression in mice, which is equivalent to 5 % povidone iodine treatment (reference standard), applied on a daily basis till complete healing.

Radio-modifying potential of Saraca indica against ionizing radiation: an in vitro study using Chinese hamster lung fibroblast (V79) cells.

This study demonstrated the radioprotective efficacy of extracts prepared from stem bark of Saraca indica (SI) against X-rays induced cellular damage, which was evaluated by a battery of cytotoxicity, genotoxicity, apoptotic, and biochemical assays using Chinese hamster fibroblast (V79) cells. Cell viability and surviving fraction were increased significantly when V79 cells were preconditioned with optimal concentration of hydroalcoholic extract (HE; 50 µg/mL) of SI for 2 h prior exposure to X-rays. Radiation induced cellular damage was correlated with a significant elevation in intracellular ROS and increased mitochondrial depolarization and loss of intracellular antioxidant enzymes. However, cells preconditioned with 50 µg/mL of HE reversed this effect. Pretreatment of HE resulted in inhibition of radiation induced GSH, GST, SOD, catalase levels, and lipid peroxidation to that of radiation-alone treated group. Also, a significant decrease in radiation induced DNA damage, apoptotic and necrotic cell death was observed in case of cells preconditioned with HE. Supporting to this HPLC analysis indicated the presence of ellagic acid as one of the major phytochemical present in HE. Thus, the maintenance of cellular redox status by pretreatment with HE, conferred protection of cellular DNA, oxidative stress by neutralizing free radicals generated by the cellular irradiation and resulted in increased in cell survival may be attributed to the presence of ellagic acid indicating SI's radioprotective potential.

Assessment of genotoxic effect of maleic acid and EDTA: a comparative in vitro experimental study.

OBJECTIVES: This study aims to evaluate and compare the genotoxic and apoptotic effect of aqueous solutions of ethylenediaminetetraacetic acid (EDTA) with that of maleic acid (MA) using Chinese hamster lung fibroblast (V79) cells growing in vitro. MATERIALS AND METHODS: Exponentially growing V79 cells were treated with various concentrations of EDTA or MA alone for 30 min, and genotoxic effect was analyzed by micronucleus as well as comet assays and the type of cell death by apoptotic cell measurements using microscopic and flow cytometric methods. For all the experiments, H2O2 was used as a positive control. RESULTS: Treatment of V79 cells with H2O2 resulted in significantly (P < 0.001) increased micronuclei and levels of DNA damage, whereas, EDTA/MA alone treated cells did not show significant increase of MN frequencies and comet parameters even at their higher concentrations when compared with that of untreated control. V79 cells treated with EDTA/MA for 30 min showed a nonsignificant increase in the percentage of apoptotic and necrotic cells at their lower concentrations (0.025 and 0.05 % for EDTA and MA, respectively). However, at higher concentrations, i.e., >IC50 (0.1 and 0.5 %) for EDTA and MA resulted in increased number of apoptotic and necrotic cells when compared with the untreated group. CONCLUSIONS: This study clearly demonstrates that MA and EDTA are not potentially genotoxic agents and MA induced lesser apoptotic/necrotic death than that of EDTA at their clinically relevant doses. CLINICAL RELEVANCE: MA may have a better clinical acceptability with comparable smear layer removal ability. Hence, the results presented here might be an additional supporting evidence for the use of MA in endodontic practice.

Protective effect of zingerone, a dietary compound against radiation induced genetic damage and apoptosis in human lymphocytes.

Zingerone a dietary compound was investigated for its ability to protect against radiation induced genotoxicity and apoptosis in human lymphocytes growing in vitro. The radiation antagonistic potential of zingerone was assessed by alkaline comet, cytokinesis-block micronucleus, apoptosis and reactive oxygen species inhibition assays. Treatment of lymphocytes with zingerone (10µg/ml) prior exposure to 2Gy gamma radiation resulted in a significant reduction of frequency of micronuclei as compared to the control set of cells evaluated by cytokinesis blocked micronucleus assay. Similarly, treatment of lymphocytes with zingerone prior to radiation exposure showed significant decrease in the DNA damage as assessed by comet parameters, such as percent tail DNA and Olive tail moment. Further, treatment with zingerone (10µg/ml) before irradiation significantly decreased the percentage of apoptotic cells analyzed microscopically method and by DNA ladder assay. Similarly, the radiation induced reactive oxygen species levels were significantly (P<0.01) inhibited by zingerone. Our study demonstrates the protective effect of zingerone against radiation induced DNA damage and antiapoptotic effect in human lymphocytes, which may be partly attributed to scavenging of radiation induced free radicals and also by the inhibition of radiation induced oxidative stress.

Antioxidant and radiation antagonistic effect of Saraca indica.

The present study was undertaken to investigate the radiation mitigating effect of hydro-alcoholic extract of Saraca indica (SIE) against mice exposed to whole body gamma radiation. Free radical scavenging ability by SIE was demonstrated using hydroxyl, superoxide anion, ABTS*+ and DPPH radicals generated in vitro. A significant increase in the animal survival (dose reduction factor = 1.39), inhibition in the decline of hematological parameters as well as increased number of spleen colony-forming units was observed when SIE was administered prior to radiation. SIE pretreatment increased the levels of glutathione, glutathione S- trans-ferase, catalase and lowered lipid peroxidation. Our findings for the first time demonstrate the protective potential of SIE against radiation induced syndromes with an optimal dose of 400 mg/kg b.wt. The radiation mitigating effect may be attributed to the mechanisms such as free radical scavenging, elevation in antioxidant status, and reduction in lipid peroxidation.

Cytotoxic, genotoxic and oxidative stress induced by 1,4-naphthoquinone in B16F1 melanoma tumor cells.

Quinones have diverse pharmacological properties including antibacterial, antifungal, antiviral, anti-inflammatory, antipyretic and anticancer activity. The cytotoxic potential of 1,4-naphthoquinone (NQ14) was studied against B16F1 melanoma cells grown in vitro. NQ14 treatment resulted in a concentration-dependent cytotoxicity as indicated by MTT assay and lactate dehydrogenase leakage assay. Depletion in cellular glutathione levels after 1h incubation with NQ14 correlated with the corresponding increase in reactive oxygen species generation as determined by 2',7'-dicholorofluorescein diacetate assay suggests the role of oxidative stress in cell death. The frequency of micronucleated binucleate cells increased with increasing doses of NQ14 with a corresponding decrease in the cytokinesis block proliferation index indicating the drug induced genotoxicity and cell division delay. Further, a dose-dependent decrease in the clonogenic cell survival indicated the potential of NQ14 to inhibit cell proliferation contributing to cell death. The cell death after NQ14 treatment may be attributed to apoptosis as seen in DNA ladder pattern along with necrosis as indicated in flow cytometric analysis of Annexin V/PI stained cells. Results of the present study demonstrate the cytotoxic and genotoxic potential of NQ14 by the induction of oxidative stress mediated mechanisms leading to tumor cell kill.