Cell Journal (Yakhteh)
Volume:17 Issue: 4, Winter 2016

Today the regulatory role of microRNAs (miRs) is well characterized in many diverse cellular processes. MiR-based regulation is categorized under epigenetic regulatory mechanisms. These small non-coding RNAs participate in producing and maturing erythrocytes, expressing hematopoietic factors and regulating expression of globin genes by post transcriptional gene silencing. The changes in expression of miRs (miR-144/-320/-451/ 503) in thalassemic/sickle cells compared with normal erythrocytes may cause clinical severity. According to the suppressive effects of certain miRs (miR-15a/-16-1/-23a/-26b/-27a/ 451) on a number of transcription factors [myeloblastosis oncogene (MYB), B-cell lymphoma 11A (BCL11A), GATA1, Krüppel-like factor 3 (KLF3) and specificity protein 1 (Sp1)] during β globin gene expression, It has been possible to increasing γ globin gene expression and fetal hemoglobin (HbF) production. Therefore, this strategy can be used as a novel therapy in infusing HbF and improving clinical complications of patients with hemoglobinopathies.

MicroRNAs (miRNAs) are a class of non-coding RNAs (ncRNAs) that transcriptionally or post-transcriptionally regulate gene expression through degradation of their mRNA targets and/or translational suppression. However, there are a few reports on miRNA-mediated expression regulation of long ncRNAs (lncRNAs). We have previously reported a significant upregulation of the lncRNA SOX2OT and its intronic coding gene, SOX2, in esophageal squamous cell carcinoma (ESCC) tissue samples. In this study, we aimed to evaluate the effect of induced overexpression of miR-211 on SOX2OT and SOX2 expression in vitro. In this experimental study, we performed both bioinformatic and experimental analyses to examine whether these transcripts are regulated by miRNAs. From the list of potential candidate miRNAs, miR-211 was found to have complementary sequences to SOX2OT and SOX2 transcripts. To validate our finding experimentally, we transfected the NT-2 pluripotent cell line (an embryonal carcinoma stem cell) with an expression vector overexpressing miR-211. The expression changes of miR-211, SOX2OT, and SOX2 were then quantified by a real-time polymerase chain reaction (RT-PCR) approach. Compared with mock-transfected cells, overexpression of miR-211 caused a significant down-regulation of both genes (P<0.05). Furthermore, flow-cytometry analysis revealed a significant elevation in sub-G1 cell population following ectopic expression ofmiR-211 in NT-2 cells. We report here, for the first time, the down-regulation of SOX2OT and SOX2 genes by an miRNA. Considering the vital role of SOX2OT and SOX2 genes in pluripotency and tumorigenesis, our data suggest an important and inhibitory role for miR-211 in the aforementioned processes.

The aim of this study was to clarify the mechanism by which lactobacilli exert their cytotoxic effects on cervical cancer cells. In addition, we aimed to evaluate the effect of lactobacilli on the expression of human papilloma virus (HPV) oncogenes. In this experimental study, using quantitative real-time polymerase chain reaction (PCR), we analyzed the expression of CASP3 and three autophagy genes [ATG14, BECN1 and alpha 2 catalytic subunit of AMPK (PRKAA2)] along with HPV18 E6 and E7 genes in HeLa cells before and after treatment with Lactobacillus crispatus and Lactobacillus rhamnosus culture supernatants. The expression of CASP3 and autophagy genes in HeLa cells was decreased after treatment with lactobacilli culture supernatants. However, this decrease was not significant for PRKAA2 when compared with controls. In addition, expression of HPV E6 was significantly decreased after treatment with lactobacilli culture supernatants. Lactobacilli culture supernatants can decrease expression of ATG14 and BECN1 as well as the HPV E6 oncogene. It has been demonstrated that the main changes occurring during cervical carcinogenesis in cell machinery can be reversed by suppression of HPV oncogenes. Therefore, downregulation of HPV E6 by lactobacilli may have therapeutic potential for cervical cancer. As the role of autophagy in cancer is complicated, further work is required to clarify the link between downregulation of autophagy genes and antiproliferative effects exerted by lactobacilli.

OCT4B1, a novel variant of OCT4, is expressed in cancer cell lines and tissues. Based on our previous reports, OCT4B1 appears to have a crucial role in regulating apoptosis as well as stress response [heat shock proteins (HSPs)] pathways. The aim of the present study was to determine the effects of OCT4B1 silencing on the expression of high molecular weight HSPs in three different human tumor cell lines. In this experimental study, OCT4B1 expression was suppressed in AGS (gastric adenocarcinoma), 5637 (bladder tumor) and U-87MG (brain tumor) cell lines using RNAi strategy. Real-time polymerase chain reaction (PCR) array was employed for expression level analysis and the fold changes were calculated using RT2 Profiler PCR array data analysis software version 3.5. Our data revealed up-regulation of HSPD1 (from HSP60 family) as well as HSPA14, HSPA1L, HSPA4, HSPA5 and HSPA8 (from HSP70 family) following OCT4B1 knock-down in all three cell lines. In contrast, the expression of HSP90AA1 and HSP- 90AB1 (from HSP90 family) as well as HSPA1B and HSPA6 (from HSP70 family) was down-regulated under similar conditions. Other stress-related genes showed varying expression pattern in the examined tumor cell lines. Our data suggest a direct or indirect correlation between the expression of OCT4B1 and HSP90 gene family. However, OCT4B1 expression was not strongly correlated with the expression of HSP70 and HSP60 gene families.

Gastric cancer (GC) is widely associated with chronic inflammation. The pro inflammatory microenvironment provides conditions that disrupt stem/progenitor cell proliferation and differentiation. The signal transducer and activator of transcription- 3 (STAT3) signaling pathway is involved in inflammation and also contributes to the maintenance of embryonic stem cell (ESCs) pluripotency. Here, we have investigated the activation status of STAT3 in GC stem-like cells (GCSLCs). In this experimental research, CSLCs derived from the human GC cell line MKN-45 and patient specimens, through spheroid body formation, characterized and then assayed for the STAT3 transcription factor expression in mRNA and protein level further to its activation. Spheroid cells showed higher potential for spheroid formation than the parental cells. Furthemore, stemness genes NANOG, c-MYC and SOX-2 were over expressed in spheroids of MKN-45 and in patient samples. In MKN-45 spheroid cells, epithelial mesenchymal transition (EMT) related markers CDH2, SNAIL2, TWIST and VIMENTIN were upregulated (P<0.05), but we observed no change in expression of the E-cadherin epithelial marker. These cells exhibited more resistance to docetaxel (DTX) when compared with parental cells (P<0.05) according to the MTS assay. Although immunostaining and Western blotting showed expression of the STAT3 protein in both spheroids and parents, the mRNA level of STAT3 in spheroids was higher than the parents. Nuclear translocation of STAT3 was accompanied by more intensive phospho-STAT3 (p-STAT3) in spheroid structures relative to the parent cells according to flow cytometry analysis (P<0.05). The present findings point to STAT3 over activation in GCSLCs. Complementary experiments are required to extend the role of STAT3 in stemness features and invasion properties of GCSCs and to consider the STAT3 pathway for CSC targeted therapy.

Three-dimensional (3D) biomimetic nanofiber scaffolds have widespread applications in biomedical tissue engineering. They provide a suitable environment for cellular adhesion, survival, proliferation and differentiation, guide new tissue formation and development, and are one of the outstanding goals of tissue engineering. Electrospinning has recently emerged as a leading technique for producing biomimetic scaffolds with micro to nanoscale topography and a high porosity similar to the natural extracellular matrix (ECM). These scaffolds are comprised of synthetic and natural polymers for tissue engineering applications. Several kinds of cells such as human embryonic stem cells (hESCs) and mouse ESCs (mESCs) have been cultured and differentiated on nanofiber scaffolds. mESCs can be induced to differentiate into a particular cell lineage when cultured as embryoid bodies (EBs) on nano-sized scaffolds. We cultured mESCs (2500 cells/100 μl) in 96-well plates with knockout Dulbecco’s modified eagle medium (DMEM-KO) and Roswell Park Memorial Institute-1640 (RPMI-1640), both supplemented with 20% ESC grade fetal bovine serum (FBS) and essential factors in the presence of leukemia inhibitory factor (LIF). mESCs were seeded at a density of 2500 cells/100 μl onto electrospun polycaprolactone (PCL) nanofibers in 96-well plates. The control group comprised mESCs grown on tissue culture plates (TCP) at a density of 2500 cells/100 μl. Differentiation of mESCs into mouse hematopoietic stem cells (mHSCs) was performed by stem cell factor (SCF), interleukin-3 (IL-3), IL-6 and Fms-related tyrosine kinase ligand (Flt3-L) cytokines for both the PCL and TCP groups. We performed an experimental study of mESCs differentiation. PCL was compared to conventional TCP for survival and differentiation of mESCs to mHSCs. There were significantly more mESCs in the PCL group. Flowcytometric analysis revealed differences in hematopoietic differentiation between the PCL and TCP culture systems. There were more CD34+ (Sca1+) and CD133+ cells subpopulations in the PCL group compared to the conventional TCP culture system. The nanofiber scaffold, as an effective surface, improves survival and differentiation of mESCs into mHSCs compared to gelatin coated TCP. More studies are necessary to understand how the topographical features of electrospun fibers affect cell growth and behavior. This can be achieved by designing biomimetic scaffolds for tissue engineering.

Bone marrow (BM) is one of the major hematopoietic organs in postnatal life that consists of a heterogeneous population of stem cells which have been previously described. Recently, a rare population of stem cells that are called very small embryonic-like (VSEL) stem cells has been found in the BM. These cells express several developmental markers of pluripotent stem cells and can be mobilized into peripheral blood (PB) in response to tissue injury. In this study we have attempted to investigate the ability of these cells to migrate toward an injured spinal cord after transplantation through the tail vein in a rat model. In this experimental study, VSELs were isolated from total BM cells using a fluorescent activated cell sorting (FACS) system and sca1 and stage specific embryonic antigen (SSEA-1) antibodies. After isolation, VSELs were cultured for 7 days on C2C12 as the feeder layer. Then, VSELs were labeled with 1,1´-dioctadecyl-3,3,3´, ´ tetramethylindocarbocyanine perchlorate (DiI) and transplanted into the rat spinal cord injury (SCI) model via the tail vein. Finally, we sought to determine the presence of VSELs in the lesion site. We isolated a high number of VSELs from the BM. After cultivation, the VSELs colonies were positive for SSEA-1, Oct4 and Sca1. At one month after transplantation, real-time polymerase chain reaction analysis confirmed a significantly increased expression level of Oct4 and SSEA-1 positive cells at the injury site. VSELs have the capability to migrate and localize in an injured spinal cord after transplantation.

This research intends to unravel the temporal expression profiles of genes involved in three developmentally important signaling pathways [transforming growth factor-β (TGF-β), fibroblast growth factor (FGF) and wingless/int (WNT)] during pre- and peri implantation goat embryo development. In this experimental study, we examined the transcripts that encoded the ligand, receptor, intracellular signal transducer and modifier, and the downstream effector, for each signaling pathway. In vitro mature MII oocytes and embryos at three distinctive stages [8-16 cell stage, day-7 (D7) blastocysts and day-14 (D14) blastocysts] were separately prepared in triplicate for comparative real-time reverse transcriptase polymerase chain reaction (RT-PCR) using the selected gene sets. Most components of the three signaling pathways were present at more or less stable levels throughout the assessed oocyte and embryo developmental stages. The transcripts for TGF-β, FGF and WNT signaling pathways were all induced in unfertilized MII-oocytes. However, developing embryos showed gradual patterns of decrease in the activities of TGF-β, FGF and WNT components with renewal thereafter. The results suggested that TGF-β, FGF and WNT are maternally active signaling pathways required during earlier, rather than later, stages of pre- and periimplantation goat embryo development.

The present study investigated the effects of gallic acid (GA) administration on trimethyltin chloride (TMT) induced anxiety, depression, and hippocampal neurodegeneration in rats. In this experimental study, the rats received intraperitoneal (i.p.) injections of TMT (8 mg/kg). The animals received either GA (50, 100 and 150 mg/kg) or saline as the vehicle for 14 consecutive days. We measured depression and anxiety levels of the rats by conducting the behavioral tail suspension (TST), elevatedplusmaze (EPM), and novelty suppressed feeding (NSF) tests. Histological analyses were then used to determine the cell densities of different hippocampal subdivisions. The data were analyzed with ANOVA and Tukey’s post hoc test. GA administration ameliorated anxiety and depression in the behavioral tests. The cell densities in the CA1, CA2, CA3 and DG hippocampal subdivisionsfrom GA-treated rats were higher than saline treated rats. GA treatment against TMT-induced hippocampal degeneration altered cellular loss in the hippocampus and ameliorated the depression-anxiety state in rats.

Bone marrow and umbilical cord stromal cells are multipotential stem cells that have the ability to produce growth factors that play an important role in survival and generation of axons. The goal of this study was to evaluate the effects of the two different mesenchymal stem cells on peripheral nerve regeneration. In this experimental study, a 10 mm segment of the left sciatic nerve of male Wistar rats (250-300 g) was removed with a silicone tube interposed into this nerve gap. Bone marrow stromal cells (BMSCs) and human umbilical cord stromal cells (HUCSCs) were respectively obtained from rat and human. The cells were separately cultured and transplanted into the nerve gap. The sciatic nerve regeneration was evaluated by immunohistochemistry, and light and electron microscopy. Moreover, histomorphology of the gastrocnemius muscle was observed. The nerve regeneration in the BMSCs and HUCSCs groups that had received the stem cells was significantly more favorable than the control group. In addition, the BMSCs group was significantly more favorable than the HUCSCs group (P<0.05). The results of this study suggest that both homograft BMSCs and heterograft HUCSCs may have the potential to regenerate peripheral nerve injury and transplantation of BMSCs may be more effective than HUCSCs in rat.

Toll like receptors (TLRs) are one of the main components of the innate immune system. It has been reported that expression of these receptors are altered in the female reproductive tract (FRT) during menstrual cycle. Here we used a fallopian tube epithelial cell line (OE-E6/E7) to evaluate the effect of two sex hormones in modulating TLR expression. In this experimental study, initially TLR gene expression in OEE6/ E7 cells was evaluated and compared with that of fallopian tube tissue using quantitative real time-polymerase chain reaction (qRT-PCR) and immunostaining. Thereafter, OE-E6/E7 cells were cultured with different concentrations of estradiol and progesterone, and combination of both. qRT-PCR was performed to reveal any changes in expression of TLR genes as a result of hormonal treatment. TLR1-10 genes were expressed in human fallopian tube tissue. TLR1-6 genes and their respective proteins were expressed in the OE-E6/E7 cell line. Although estradiol and progesterone separately had no significant effect on TLR expression, their combined treatment altered the expression of TLRs in this cell line. Also, the pattern of TLR expression in preovulation (P), mensturation (M) and window of implantation (W) were the same for all TLRs with no significant differences between P, M and W groups. These data show the significant involvement of the combination of estradiol and progesterone in modulation of TLR gene expression in this human fallopian tube cell line. Further experiments may reveal the regulatory mechanism and signalling pathway behind the effect of sex hormones in modulating TLRs in the human FRT.

Neutrophils have an important role in the rapid innate immune response, and the release or active secretion of elastase from neutrophils is linked to various inflammatory responses. Purpose of this study was to determine how the human neutrophil elastase affects the interleukin-10 (IL-10) response in peripheral blood mononuclear cells (PBMC). In this prospective study, changes in IL-10 messenger RNA (mRNA) and protein expression levels in monocytes derived from human PBMCs were investigated after stimulation with human neutrophil elastase (HNE). A set of inhibitors was used for examining the pathways for IL-10 production induced by HNE. Reverse transcription polymerase chain reaction (RT-PCR) showed that stimulation with HNE upregulated IL-10 mRNA expression by monocytes, while the enzyme-linked immunosorbent assay (ELISA) revealed an increase of IL-10 protein level in the culture medium. A phospholipase C inhibitor (U73122) partially blunted the induction of IL-10 mRNA expression by HNE, while IL-10 mRNA expression was significantly reduced by a protein kinase C (PKC) inhibitor (Rottlerin). A calcium chelator (3,4,5-trimethoxybenzoic acid 8-(diethylamino)octyl ester: TMB-8) inhibited the response of IL-10 mRNA to stimulation by HNE. In addition, pretreatment with a broad-spectrum PKC inhibitor (Ro-318425) partly blocked the response to HNE. Finally, an inhibitor of PKC theta/delta abolished the increased level of IL-10 mRNA expression. These results indicate that HNE mainly upregulates IL-10 mRNA expression and protein production in moncytes via a novel PKC theta/delta, although partially via the conventional PKC pathway.

Bone marrow has recently been recognized as a novel source of stem cells for the treatment of wide range of diseases. A number of studies on murine bone marrow have shown a homogenous population of rare stage-specific embryonic antigen 1 (SSEA-1) positive cells that express markers of pluripotent stem cells. This study focuses on SSEA-1 positive cells isolated from murine bone marrow in an attempt to differentiate them into insulin-secreting cells (ISCs) in order to investigate their differentiation potential for future use in cell therapy. This study is an experimental research. Mouse SSEA-1 positive cells were isolated by Magnetic-activated cell sorting (MACS) followed by characterization with flow cytometry. Induced SSEA-1 positive cells were differentiated into ISCs with specific differentiation media. In order to evaluate differentiation quality and analysis, dithizone (DTZ) staining was use, followed by reverse transcription polymerase chain reaction (RT-PCR), immunocytochemistry and insulin secretion assay. Statistical results were analyzed by one-way ANOVA. The results achieved in this study reveal that mouse bone marrow contains a population of SSEA-1 positive cells that expresses pluripotent stem cells markers such as SSEA-1, octamer-binding transcription factor 4 (OCT-4) detected by immunocytochemistry and C-X-C chemokine receptor type 4 (CXCR4) and stem cell antigen-1 (SCA-1) detected by flow cytometric analysis. SSEA-1 positive cells can differentiate into ISCs cell clusters as evidenced by their DTZ positive staining and expression of genes such as Pdx1 (pancreatic transcription factors), Ngn3 (endocrine progenitor marker), Insulin1 and Insulin2 (pancreaticβ-cell markers). Additionally, our results demonstrate expression of PDX1 and GLUT2 protein and insulin secretion in response to a glucose challenge in the differentiated cells. Our study clearly demonstrates the potential of SSEA-1 positive cells to differentiate into insulin secreting cells in defined culture conditions for clinical applications.

The close relationship between energy metabolism, nutritional state, nd eproductive physiology suggests that nutritional and metabolic disorders can disrupt ormal reproductive function and fertility. Considering the importance of leptin and hrelin effects in regulation of the hypothalamic-pituitary-gonadal axis, the objective f this study was to investigate the influence of obesity and centrally applied ghrelin n immunohistochemical appearance and quantitative morphology of the pituitary ollicle-stimulating hormone (FSH) and luteinizing hormone (LH) producing cells in dult male rats. In this experimental study, animals were given two ifferent iets: normal-fat (NF) and high-fat (HF), for 4 weeks, corresponding to normal nd positive energy balance (n=2×14), respectively. Each group was subsequently ivided into two subgroups (n=7) receiving intracerebroventricular (ICV) injections of ither ghrelin [G, 1 μg/5 μL phosphate buffered saline (PBS)] or vehicle (5 μL PBS, ontrol group) every 24 hours for five consecutive days. Morphometric analyses showed that in HF control group, the ercentage of SH cells per unit volume of total pituitary gland tissue (in μm3), i.e. volume density Vvc), was increased (P<0.05) by 9.1% in comparison with the NF controls. After CV treatment with ghrelin, volume (Vc) and volume density (Vvc) of FSH cells in hrelin+NF (GNF) and ghrelin+HF (GHF) groups remained unchanged in comparison ith NF and HF controls. Volume of LH cells in HF control group was increased by 7% (P<0.05), but their Vvc was decreased by 8.3% (P<0.05) in comparison with F controls. In GNF group, the volume of LH cells increased by 7% (P<0.05), in omparison with the NF controls, but in GHF group, the same parameter remained nchanged when compared with HF controls. The central application of ghrelin ecreased he Vvc of LH cells only in GNF group by 38.9% (P<0.05) in comparison with he NF control animals. The present study has shown that obesity and repetitive ICV dministration f low doses of ghrelin, in NF and HF rats, modulated the immunohistomorphometric eatures of gonadotrophs, indicating the importance of obesity and ghrelin in regulation f he reproductive function.

To evaluate the effect of Exendine-4 (EX-4), a Glucagon-like peptide 1 (GLP-1) receptor agonist, on the differentiation of insulin-secreting cells (IPCs) from rat adipose-derived mesenchymal stem cells(ADMSCs). In this experimental study, ADMSCs were isolated from rat adipose tissue and exposed to induction media with or without EX-4. After induction, the existence of IPCs was confirmed by morphology analysis, expression pattern analysis of islet-specific genes (Pdx-1, Glut-2 and Insulin) and insulin synthesis and secretion. IPCs induced in presence of EX-4 were morphologically similar to pancreatic islet-like cells. Expression of Pdx-1, Glut-2 and Insulin genes in EX-4 treated cells was significantly higher than the cells exposed to differentiation media without EX-4. Compared to EX-4 untreated ADMSCs, insulin release from EX-4 treated ADMSCs showed a nearly 2.5 fold (P<0.05) increase when exposed to a high glucose (25 mM) medium. The percentage of insulin positive cells in the EX-4 treated group was approximately 4-fold higher than in the EX-4 untreated ADMSCs. The present study has demonstrated that EX-4 enhances the differentiation of ADMSCs into IPCs. Improvement of this method may help the formation of an unlimited source of cells for transplantation.

Multi-drug resistance (MDR) is a controversial issue in traditional chemotherapy of aggressive cancers, including hepatocellular carcinoma. The major cause of MDR is suggested to be the aberrant activation of the main signaling pathways such as Wnt and nuclear factor kappa-light-chain-enhancer of activated B cells (NF- κB) which have key roles in the maintenance of cancer stem cells (CSCs). Therefore, the evaluation of their alterations could be essential in chemo-resistant cancers such as Hepatocellular carcinoma. The main purpose of this study was to investigate the alteration of the mentioned pathways in the chemotherapy resistant cancer cells by assessing their major molecular parameters. In this experimental study, methylthiazol tetrazolium (MTT) assay, acridine orange/ethidium bromide (AO/EtBr) and Hoechst 33342 staining, DNA fragmentation and colony formation methods were employed to investigate the cytotoxic effects of methotrexate (MTX) and doxorubicin (DOX) on PLC/PRF/5 cells. Moreover, the expression of 11 important genes involved in MDR was performed by semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). PLC/PRF/5 cells (Alexander) were sensitive to DOX and normally resistant to MTX. In addition, the results obtained from RT-PCR analysis revealed that β-catenin expression was significantly reduced and ABCG2 significantly overexpressed 4.85 and 3.34 times (P value<0.05) in DOX and MTX treated cells, respectively. Furthermore, a considerable expression of HIF-1α and p65 were detected only in MTX-resistant cells. Anti-cancer drugs may have more than one target in tumor cells. They not only participate in deregulation of Wnt but also alter NF-κB activation. Moreover, HIF-1α was the only anti-apoptotic protein that was significantly induced in the chemoresistant cells.

Organophosphorus (OP) compounds are used to control pests, however they can reach the food chain and enter the human body causing serious health problems by means of acetylcholinesterase (AChE) inhibition and oxidative stress (OS). Among the OPs, chlorpyrifos (CHP), malathion (MAL), and diazinon (DIA) are commonly used for commercial extermination purposes, in addition to veterinary practices, domestic, agriculture and public health applications. Two new recently registered medicines that contain selenium and other antioxidants, IMOD and angipars (ANG), have shown beneficial effects for OS related disorders. This study examines the effect of selenium-based medicines on toxicity of three common OP compounds in erythrocytes. In the present experimental study, we determined the efficacy of IMOD and ANG on OS induced by three mentioned OP pesticides in human erythrocytes in vitro. After dose-response studies, AChE, lipid peroxidation (LPO), total antioxidant power (TAP) and total thiol molecules (TTM) were measured in erythrocytes after exposure to OPs alone and in combined treatment with IMOD or ANG. AChE activity, TAP and TTM reduced in erythrocytes exposed to CHP, MAL and DIA while they were restored in the presence of ANG and IMOD. ANG and IMOD reduced the OPs-induced elevation of LPO. The present study shows the positive effects of IMOD and ANG in reduction of OS and restoration of AChE inhibition induced by CHP, MAL and DIA in erythrocytes in vitro.

Many studies have been published on the antioxidative effects of boric acid (BA) and sodium borates in in vitro studies. However, the boron (B) concentrations tested in these in vitro studies have not been selected by taking into account the realistic blood B concentrations in humans due to the lack of comprehensive epidemiological studies. The recently published epidemiological studies on B exposure conducted in China and Turkey provided blood B concentrations for both humans in daily life and workers under extreme exposure conditions in occupational setting. The results of these studies have made it possible to test antioxidative effects of BA in in vitro studies within the concentration range relevant to humans. The aim of this study was to investigate the protective effects of BA against oxidative DNA damage in V79 (Chinese hamster lung fibroblast) cells. The concentrations of BA tested for its protective effect was selected by taking the blood B concentrations into account reported in previously published epidemiological studies. Therefore, the concentrations of BA tested in this study represent the exposure levels for humans in both daily life and occupational settings. In this experimental study, comet assay and neutral red uptake (NRU) assay methods were used to determinacy to toxicity and genotoxicity of BA and hydrogen peroxide (H2O2). The results of the NRU assay showed that BA was not cytotoxic within the tested concentrations (3, 10, 30, 100 and 200 μM). These non-cytotoxic concentrations were used for comet assay. BA pre-treatment significantly reduced (P<0.05, one-way ANOVA) the DNA damaging capacity of H2O2 at each tested BA concentrations in V79 cells. Consequently, pre-incubation of V79 cells with BA has significantly reduced the H2O2-induced oxidative DNA damage in V79 cells. The protective effect of BA against oxidative DNA damage in V79 cells at 5, 10, 50, 100 and 200 μM (54, 108, 540, 1080, and 2161 ng/ml B equivalents) concentrations was proved in this in vitro study.