Iranian Journal of Basic Medical Sciences
Year:2017 | Volume:20 | Issue:8|Papers Count:15

The beneficial effects of fluoride on human oral health are well studied. There are numerous studies demonstrating that a small amount of fluoride delivered to the oral cavity decreases the prevalence of dental decay and results in stronger teeth and bones. However, ingestion of fluoride more than the recommended limit leads to toxicity and adverse effects. In order to update our understanding of fluoride and its potential toxicity, we have described the mechanisms of fluoride metabolism, toxic effects, and management of fluoride toxicity. The main aim of this review is to highlight the potential adverse effects of fluoride overdose and poorly understood toxicity. In addition, the related clinical significance of fluoride overdose and toxicity has been discussed.

Objective(s): Acinetobacter baumannii has a high propensity to form biofilm and frequently causes medical device-related infections with multiple-drug-resistance in hospitals. The aim of this work is to study antimicrobial resistance and the role of bap and cpa A genes in biofilm formation by A. baumannii to understand how this pathogen persists in the hospital environment.Materials and Methods: The antibiotic resistance profile and in vitro biofilm-forming ability of one hundred clinical isolates of A. baumannii was evaluated by disc diffusion and crystal-violet staining methods, respectively. Isolates were tested for the presence of bap and cpaA genes.Results: The isolates were highly resistant to cefepime, third-generation cephalosporins, ciprofloxacin, cotrimoxazole, aminoglycosides and carbapenems. Moreover, four isolates were resistant to colistin. Quantification of biofilm showed that 43% of the isolates were strong biofilm-producer. Furthermore, 32% of the isolates exhibited moderate biofilm-formation and showed initial binding activity. Frequency of bap and cpaA were determined 92% and 36%, respectively.Conclusion: There was strong association between the presence of bap gene and biofilm formation by A. baumannii isolates (P=0.003). In addition, multidrug resistant isolates produced stronger biofilm than other isolates (P=0.0001). These results indicate importance of biofilm in resistance of isolates and effect of presence of bap gene in biofilm formation by A. baumannii strains.

Objective(s): The aim of the present study was to investigate the effects of genistein and exercise on the spatial memory and expression of microRNA-132, BDNF, and IGF-1 in the hippocampus of ovariectomized rats.Materials and Methods: Sixty animals were divided into six groups of control, sham, ovariectomy (OVX), ovariectomized with 8 weeks of genistein administration (OVX.G), with 8 weeks of swimming training (OVX.E), and with 8 weeks of both of them (OVX.G.E). The effect of genistein and/or exercise was evaluated by measuring microRNA-132, BDNF, and IGF-1 expression levels in the hippocampus tissue. Grafts were analyzed using Real-time polymerase chain reaction for microRNA-132, BDNF, IGF-1, and spatial memory via a Morris water maze (MWM).Results: Our findings showed that ovariectomy decreased the expression of microRNA-132, BDNF, and IGF-1 in the hippocampus (P<0.05) in comparison with the sham group as well as performance in the water maze (P<0.05). Also according to results ovariectomized groups that were treated with genistein/exercise or both of them showed significant difference in expression of microRNA-132, BDNF, and IGF-1 in the hippocampus (P<0.05) and decreased latency in MWM (P<0.05) compared with the OVX group but combination treatment was more effective in the OVX.G.E group in comparison with OVX.E and OVX.G groups.Conclusion: Overall our results emphasized that combination treatment with genistein and exercise could improve microRNA-132, BDNF, and IGF-1 expression in the hippocampus as well as the spatial memory of ovariectomized rats. These effects may have beneficial impacts on the menopausal period.

Objective(s): Stroke is known as a main cause of mortality and prolonged disability in adults. Both transient receptor potential V1 (TRPV1) channels and toll-like receptors (TLRs) are involved in mediating the inflammatory responses. In the present study, the effects of TRPV1 receptor activation and blockade on stroke outcome and gene expression of TLR2 and TLR4 were assessed following permanent middle cerebral artery occlusion in rats Materials and Methods: Eighty male Wistar rats were divided into four groups as follows: sham, vehicle, AMG9810 (TRPV1 antagonist) -treated and capsaicin (TRPV1 agonist) -treated. For Stroke induction, the middle cerebral artery was permanently occluded and then behavioral functions were evaluated 1, 3 and 7 days after stroke.Results: TRPV1 antagonism significantly reduced the infarct volume compared to the stroke group. Also, neurological deficits were decreased by AMG9810 seven days after cerebral ischemia. In the ledged beam-walking test, the slip ratio was enhanced following ischemia. AMG9810 decreased this index in stroke animals. However, capsaicin improved the ratio 3 and 7 days after cerebral ischemia. Compared to the sham group, the mRNA expression of TLR2 and TLR4 was significantly increased in the stroke rats. AMG9810 Administration significantly reduced the mRNA expression of TLR2 and TLR4. However, capsaicin did not significantly affect the gene expression of TLR2 and TLR4.Conclusion: Our results demonstrated that TRPV1 antagonism by AMG9810 attenuates behavioral function and mRNA expression of TLR2 and TLR4. Thus, it might be useful to shed light on future therapeutic strategies for the treatment of ischemic stroke.

Objective(s): This study was aimed at investigating immune activations of the 2, 4, 6-trinitrobenzene sulfonic acid (TNBS) -induced colitis model in colonic mucosa by immunohistochemical and Western blot methods.Materials and Methods: For this purpose, 16 female Wistar albino rats were divided into two random groups of control (n=8) and colitis (n=8). The experimental colitis model was induced by intracolonic administration of TNBS (25 mg/rat). Control animals received only rectal saline for the same time. The animals were sacrificed on the 15th day after TNBS administration, and colon tissue was removed and examined morphologically. Colon samples were stained immunohistochemically with anti-CD3, anti-CD4, anti-CD5, anti-CD8, anti-CD11b, anti-CD45, anti-TNF-a, anti-IL-17, anti-IL-22 and anti-IL-23 antibodies. Additionally, the colonic tissue IL-17 and IL-22 expressions were examined by the Western blot method.Results: In the experimental results, it was determined that there was a significant decrease in body weight and an increase in colon weight in the colitis group when comparing initial experiments. The colon tissue ulcerations, inflammation, crypt loss and Goblet cell loss were observed in the colitis group in microscopic examinations. The immunohistochemical positive cell numbers significantly increased in the colitis group. The immunoreactive lymphocytes in the propria, intracryptal and submucosal layers were found to be increased in the colitis group of rats. In addition, IL-17 and IL-23 expressions were increased in colitis colon mucosa found by Western blot analysis.Conclusion: The Th17/IL-23 pathway and IL-22 serve important roles in the pathogenesis of ulcerative colitis, and will be further examined by study.

Objective(s): Mutations in the UGT1A1 gene are responsible for hyperbilirubinemia syndromes including Crigler-Najjar type 1 and 2 and Gilbert syndrome. In view of the genetic heterogeneity and involvement of large numbers of the disease causing mutations, the application of polymorphic markers in the UGTA1 gene could be useful in molecular diagnosis of the disease.Materials and Methods: In the present study, two polymorphic markers including rs4148326 and rs4124874 in the UGT1A1 gene region were characterized. The markers were selected using bioinformatics analysis of the UGT1A1 gene region and genotyped in 212 unrelated healthy individuals and 13 family trios in the Iranian population using Tetra-Primer ARMS PCR technique. The allele frequency and population status of the alleles were estimated using GENEPOP, FBAT, PowerMarker and Arlequin software.Results: The results indicated that in the case of rs4148326 marker, allele frequency for T and C allele was 66.04% and 33.96%, respectively. For rs4124874 marker, allele frequency for G and T alleles was 39.4% and 60.6%, respectively. The values of heterozygosity index for the markers examined were 64.1 for rs4148326 and 72.1 for rs4124874, respectively. The haplotype estimation analysis of the markers resulted in three informative haplotypes with frequencies≥0.05. Moreover, the results suggested the presence of linkage disequilibrium between two markers.Conclusion: Altogether, the data suggested that rs4148326 and rs4124874 could be introduced as informative markers for molecular diagnosis of Crigler-Najjar type 1 and 2 and Gilbert syndrome in the Iranian population.

Objective(s): Increasing evidence in both experimental and clinical studies suggests that oxidative stress plays a major role in the pathogenesis of multiple sclerosis. The aim of the present work is to investigate the protective effects of erythropoietin against cuprizone-induced oxidative stress.Materials and Methods: Adult male C57BL/6J mice were fed a chow containing 0.2 % cuprizone for 6 weeks. After 3 weeks, mice were simultaneously treated with erythropoietin (5, 000 IU/ kg body weight) by daily intraperitoneal injections.Results: Our results showed that cuprizone induced oxidative stress accompanied with down-regulation of subunits of the respiratory chain complex and demyelination of corpus callosum. Erythropoietin antagonized these effects. Biochemical analysis showed that oxidative stress induced by cuprizone was regulated by erythropoietin. Similarly, erythropoietin induced the expression of subunits of the respiratory chain complex over normal control values reflecting a mechanism to compensate cuprizone-mediated down-regulation of these genes.Conclusion: The data implicate that erythropoietin abolishes destructive cuprizone effects in the corpus callosum by decreasing oxidative stress and restoring mitochondrial respiratory enzyme activity.

Objective(s): The present study was aimed to evaluate the time-mannered and dose-dependent effects of 5a-dihydrotestosterone (5a-DHT) on the proliferation and differentiation of bone forming cells using MC3T3-E1 cells.Materials and Methods: Cell proliferation was analyzed using MTS and phase contrast microscopic assays. Osteogenic differentiation was assessed through a series of in vitro experiments including crystal violet staining, alkaline phosphatase (ALP) activity, and Van Gieson (VG) staining. Taken together, the efficiency of bone mineralization was examined by using alizarin red s (ARS) staining, Von Kossa staining, scanning electron microscopy (SEM) and energy dispersive x-ray (EDX) analysis.Results: The resulting data revealed that 5a-DHT exhibits promising potential particularly at a dose of 0.1 ng/ml, in promoting the growth of MC3T3-E1 cells compared to the control group (CN). Moreover, a significantly higher ALP activity was evident in the experimental group treated with 5α-DHT compared to the CN group at various time intervals. MC3T3-E1 cells treated with 5α-DHT also expressed a remarkably higher collagen deposition and mineralization (calcium and phosphate contents) compared to the CN group at various time intervals.Conclusion: Conclusively, we suggest that 5a-DHT exhibits outstanding potential of promoting proliferation and differentiation in osteoblasts which could be the in vitro basis for the efficacy of 5α-DHT in the treatment of androgen-deficient male osteoporosis.

Objective(s): Rapamycin is an immunosuppressant compound with a broad spectrum of pharmaco-logical activities. In recent years, it has been used successfully to decrease ischemia-reperfusion injury in several organ systems. The purpose of the present study was to examine the effect of rapamycin on testicular ischemia-reperfusion injury.Materials and Methods: Seventy-two adult male Wistar rats were divided into six groups: control (group1), sham-operated (Group2), T/D+DMSO as vehicle group (group3), and groups 4–6; respectively received 0.5, 1, and 1.5 mgkg-1 of rapamycin, IP 30 min before detorsion. Ischemia was achieved by twisting the right testis 720o clockwise for 1 hr. The right testis of 6 animals from each group were excised 4 hr after detorsion for the measurement of lipid peroxidation, caspase-3, and antioxidant enzyme activities. Histopathological changes and germ cell apoptosis were determined by measuring mean of seminiferous tubules diameters (MSTD) and TUNEL test in right testis of 6 animals per group, 24 hr after detorsion.Results: Testicular T/D caused increases in the apoptosis, malondialdehyde (MDA), and caspase-3 levels and decreases in the superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities in ipsilateral testis (P<0.001). The rats treated with rapamycin had significant decreases in the MDA and caspase-3 levels and significant increases in the SOD, CAT and GPx activities in ipsilateral testis compared with the T/D group (P<0.001); germ cell apoptosis was decreased, and MSTD was improved.Conclusion: Rapamycin administration during testicular torsion decreased ischemia/reperfusion (I/R) cellular damage.

Objective(s): The aim of the present study was to determine the aminoglycoside modifying enzymes (AMEs) encoded genes, tetracycline resistance genes, and the coa based typing of Staphylococcus aureus isolates in the Southwest of Iran.Materials and Methods: Antimicrobial susceptibility of isolates was carried out by agar disk diffusion methods. Two sets of multiplex PCR mixture were used for detection of AME genes and tet genes. All of the isolates were typed with the coagulase gene typing method. Of the 121 isolates, 29.75% and 47.93% were resistant to at least one aminoglycosides and tetracyclines, respectively.Results: The aac (6') -Ie-aph (2' ') was the most frequent gene (97.22%), and aph (3') -IIIa and ant (4') -Ia genes were detected in 61.11% and 11.11% of aminoglycoside resistant isolates, respectively. The tet K and tet M genes were detected in 82.75% and 56.9% of tetracycline resistant isolates, respectively. Overall 31.4% of isolates were MRSA. Totally 17 distinct coa gene RFLP patterns, numbered C1 to C17, were observed. The C5 was the most frequent coa type with 31 isolates.Conclusion: The aac (6') -Ie-aph (2'') and aph (3') -IIIa genes were the most important genes contributing to aminoglycosides resistance, while resistance to tetracyclines was mediated by tet K and tet M genes. Interestingly all S. aureus with C5 as the most prevalent coa -type were resistant to at least one of the aminoglycoside antibiotics and tetracycline simultaneously. Moreover, 30 out of 31 isolates with this coa type were MRSA, indicating the importance of the C5 coa -type in MRSA strains and also in isolates that were resistant to aminoglycosides and tetracycline.

Objective(s): Helicobacter pylori are among most common human pathogens affecting at least half of the world’s population. Mobility is one of the important primary factors in bacterial colonization and invasion. The purpose of this research is cloning, expression, and purification of FlaA protein specific epitopes in order to evaluate their antigenicity and immunogenicity.Materials and Methods: The antigenic region of the flaA gene was bioinformatically predicted using Epitope mapping software’s and the predicted epitopes were expressed in a prokaryotic expression vector. The antigen was injected into the animal model (mice BALB/c) and some indicators including IgG1, IgG2a, IgA, IFN-g, and IL 5 were measured.Results: The immunogenicity studies in animal models by measuring serum antibodies (IgG1, IgG2a, and IgA) and cytokines (IFN-g and IL5) revealed that the rFlaA induces a proper immune response in animal models.Conclusion: The recombinant FlaA protein is antigenic and immunogenic. Therefore, it might be used in order to design of specific diagnostic kits and recombinant vaccines against H. pylori.

Objective(s): Long term consumption of ethanol may induce damage to many organs. Ethanol induces its noxious effects through reactive oxygen species production, and lipid peroxidation and apoptosis induction in different tissues and cell types. Previous experiments have indicated the antioxidant characteristics of thymoquinone, the active constituent of Nigella sativa fixed oil, against biologically dangerous reactive oxygen species. This experiment was planned to evaluate the protective effect of thymoquinone against subchronic ethanol toxicity in rats.Materials and Methods: Experiments were performed on six groups. Each group consisted of six animals, including control group (saline, gavage), ethanol-receiving group (3 g/kg/day, gavage), thymoquinone (2.5, 5, 10 mg/Kg/day, intraperitoneally (IP)) plus ethanol and thymoquinone (10 mg/Kg/day, IP) groups. Treatments were carried out in four weeks.Results: Thymoquinone reduced the ethanol-induced increase in the lipid peroxidation and severity of histopathological alteration in liver and kidney tissues. In addition it improved the levels of proinflammatory cytokines in liver tissue. Furthermore, thymoquinone corrected the liver enzymes level including alanine transaminase, aspartate transaminase and alkaline phosphatase in serum and glutathione content in liver and kidney tissues. Other experiments such as Western blot analysis and quantitative real-time RT-PCR revealed that thymoquinone suppressed the expression of Bax/Bcl-2 ratio (both protein and mRNA level), and caspases activation pursuant to ethanol toxicity.Conclusion: This study indicates that thymoquinone may have preventive effects against ethanol toxicity in the liver and kidney tissue through reduction in lipid peroxidation and inflammation, and also interrupting apoptosis.

Objective(s): The population in Iran is a genetic admixture of the ancestral Aryan and other populations neighboring Iran. Different ethnic groups in Iran show wide regional distributions for many human leukocyte antigen (HLA) alleles. Therefore, it is necessary and sensible to study the differences in HLA allele distribution in different area. We studied the HLA class I and II allele frequencies in a large unrelated healthy Iranian population from Mashhad in the Northeast region.Materials and Methods: Five hundred unrelated healthy adult individuals borne and living in Mashhad, Northeast of Iran, were genotyped for HLA-A, B and HLA-DRB1 alleles using PCR with low resolution sequence specific primers (SSP-PCR) technique.Results: A total of 14 HLA-A, 24 HLA-B and 10 HLA-DRB1 alleles were spread throughout the studied population with distinct allele frequencies. At the HLA-A locus, HLA-A*02 was found to be the most frequent allele, with a frequency of 20.9%. The most common HLA-B alleles was B*35 (16.4%). The two most common observed alleles in HLA class II alleles were DRB1*15 (20.0%) followed by DRB1*13 (16.2%).Conclusion: This study is the first on the HLA class I and II allele frequencies in Northeastern Iranian population living in Mashhad. Distribution of HLA-A and B loci showed some similarities with those of other Iranians. Some difference in HLA-DRB1 polymorphisms however was observed. Considering the highly mixed population of Mashhad, the finding was not unexpected.

Objective(s): High-glucose (HG) stress, a mimic of diabetes mellitus (DM) in culture cells, alters expression of a large number of genes including Wnt and NF-kB signaling-related genes; however, the role of Wnt signaling during HG-mediated fibroblast damage and the relationship between Wnt and NF-kB signaling have not been understood. In this study, we aimed to investigate the ffects of Wnt signaling on HG-mediated damages.Materials and Methods: Wnt3a was treated to HG-stressed human primary foreskin fibroblasts and the levels of Wnt signaling markers and cell proliferation were monitored. In addition, Wnt3a and NF-κB signaling inhibitor were assisted to analyze the relationship between two pathways.Results: The results indicated that HG treatment repressed β-catenin level, and Wnt3a treatment increased the levels of b-catenin and FZD8 as well as cell proliferation. RNA-seq based transcriptome analysis identified 207 up-regulated and 200 down-regulated genes upon Wnt3a supply. These altered genes are distributed into 20 different pathways. In addition, gene ontology (GO) analysis indicates that 20 GO terms are enriched. Wnt signaling genes were further verified by qRT-PCR and the results were similar with RNA-seq assay. Since NF-kB signaling negatively regulates Wnt marker gene expression, Bay117082, a typical NF-kB signaling inhibitor and Wnt3a were supplemented for testing b-catenin and phosphorylated IkBa(p-IkBa), respectively.Conclusion: HG positively inhibits Wnt signaling, and signaling activation via supplementation of Wnt3a rescued the defect caused by HG. NF-kB signaling negatively regulates accumulation of b-catenin, but Wnt signaling has no effects on IκBα activation.

Objective(s): In the present study the effect of stress on monkeys that had learned to retrieve food from a five-chamber receptacle, as well as the relationship between their behavior and the serum cortisol and epinephrine levels and relative size of the amygdala was evaluated.Materials and Methods: Six male rhesus monkeys were individually given access to the food reward orderly. They could easily retrieve the rewards from all chambers except for the chamber 4, which a brief, mild electric shock (3 V) was delivered to them upon touching the chamber’s interior. The coping behaviors were video-recorded and analyzed offline. Baseline serum cortisol and epinephrine levels were measured before the experiments using monkey enzyme-linked immunosorbent assay kit. One week after the behavioral experiment, the monkeys’ brains were scanned using magnetic resonance imaging under general anesthesia. The cross-sectional area of the left amygdala in sagittal plane relative to the area of the whole brain in the same slice was evaluated by the planimetric method using ImageJ software.Results: Exposure to the distressing condition caused different behavioral responses. Monkeys with higher baseline levels of serum cortisol and epinephrine and larger amygdala behaved more violently in the face of stress, indicating adopting emotion-focused stress-coping strategies. Conversely, those with low plasma epinephrine, moderate cortisol, and smaller amygdala showed perseverative behavior, indicating a problem-focused coping style.Conclusion: In dealing with the same stress, different responses might be observed from nonhuman primates according to their cortisol and epinephrine levels as well as their amygdala dimensions.