Silver nanoparticles modify hypothalamic-pituitary-interrenal axis and block cortisol response to an acute stress in zebrafish, Danio rerio

The present study aimed at assessing the effects of exposure to silver nanoparticle (AgNP) and a subsequent acute stress on the expression of various genes involved in the hypothalamus-pituitary-interrenal (HPI) axis in zebrafish, Danio rerio. The fish were exposed to 0 (Control), 0.1 (LC), 0.4 (MC), and 1.2 (HC) mg Ag/L (as AgNP) over a 2-week period, followed by an acute air exposure stress. The whole body cortisol and the expression of selected genes in the fish brain and kidney were analyzed, before and after the acute stress. The results showed that AgNP increased basal cortisol levels and the expression of corticotropin releasing factor, prohormone convertase 1, pro-opiomelanocortin, and melanocortin 2 receptor; however, it suppressed/inhibited whole body cortisol, brain corticotropin releasing factor responses, pro-opiomelanocortin, and the kidney melanocortin 2 receptor responses to the acute stress. AgNP down-regulated the expression of the steroidogenic acute regulatory protein, but it intensified the gene expression in response to the acute stress. Before the acute stress, LC treatment exhibited an up-regulation in Cytochrome P450-11A-1 expression, but MC and HC treatments induced down-regulation. After the acute stress, the AgNP-exposed fish exhibited decreased Cytochrome P450-11A-1 expressions, compared with the Control. Exposure to AgNP significantly increased Cytochrome P450-11B expression. However, after the acute stress, LC treatment exhibited an up-regulation, but MC and HC treatments exhibited down-regulation in the Cytochrome P450-11B gene expression. In conclusion, AgNP suppressed cortisol response to stress, which appears to be a consequence of alterations in the HPI axis at the transcriptomic levels.

Hepatic transcriptomic and histopathological responses of common carp, Cyprinus carpio, to copper and microplastic exposure

The combined effects of copper and polyvinyl chloride (PVC) microparticles were investigated on the metal accumulation, histopathological biomarkers, and targeted transcriptomics in Cyprinus carpio liver. The fish were exposed to 0.25 mg/L copper and/or 0.5 mg/L PVC microparticles over a 14-d period. The results showed that hepatic copper accumulation is facilitated by the PVC microparticles presence in water. All treatments induced significant hepatic stress and inflammation; however, the transcriptional responses involving in detoxification pathways and apoptotic mechanisms were mixed and often down-regulated in the fish exposed to copper and/or PVC microparticles. Exposure to copper and/or PVC microparticles induced hypermeia, leukocyte infiltration and increase in melanomacrophage centers number and area. Generally, the severity of the lesions was in the following order: PVC microparticles < copper < copper+ PVC microparticles. In conclusion, PVC MPs act as a copper vector, facilitating accumulation of copper in the fish liver and increasing the tissue damage.

Fabrication of nano-decorated ZnO-fibrillar chitosan exhibiting a superior performance as a promising replacement for conventional ZnO

In this research, bioactive nano-hybrids based on the nano-fibrillar chitosan-ZnO (NF-CS-ZnO) were synthesized to diminish the toxicity of ZnO-NPs. The successful formation of nano-hybrids was confirmed by FT-IR, UV-Vis, and FE-SEM analyses, showing a uniform spherical ZnO-NPs with an average diameter of 20-30 nm, homogeneously dispersed on NF-CS. The obtained results demonstrated a remarkable antibacterial activity of NF-CS-ZnO-0.6 nano-hybrid against E. coli and S. aureus and, interestingly, no cytotoxic on normal cells (even at a high concentration of 100 μg/mL). Furthermore, NF-CS hybridization efficiently decreased the up-regulation in Cas3, Cas9, and Il6 of inspected fishes compared to the ZnO-NPs. Histopathological examination revealed hepatocyte necrosis in the fish exposed to ZnO-NPs and hyperemia exposed to NF-CS-ZnO-0.6 nano-hybrid. Finally, NF-CS efficiently improved the bio-safety and bactericidal activity of ZnO-NPs; therefore, NF-CS-ZnO nano-hybrid is prominently recommended as a talented low-toxicity antibacterial agent replacement of conventional ZnO-NPs for use in different applications.

Enhanced radiotherapy efficacy of breast cancer multi cellular tumor spheroids through in-situ fabricated chitosan-zinc oxide bio-nanocomposites as radio-sensitizing agents

Overwhelming evidence has shown that three-dimensional multicellular tumor spheroids (MCTSs) as a mimic of in-vivo tumor can accurately exhibit cellular responses to treatments. So, we compared the capability of pure zinc oxide nanoparticles (ZnO-NPs) and chitosan-ZnO bio-nanocomposites (CS-ZnO BNCs) for enhancing the radiosensitization of MDA-MB-231 breast cancer cells (BCCs) in the 3D-MCTSs model. ZnO-NPs and CS-ZnO BNCs were synthesized by a facile co-precipitation method. FE-SEM images revealed that the uniform spherical ZnO-NPs with an average diameter of 35 nm were successfully dispersed on chitosan. MDA-MB-231 MCTSs which were formed in a non-adherent culture plate, possessed functional features of in-vivo tumor. The priority of such culture method to conventionally used 2D monolayer (or parental) cell culture is the mimicking of tumor microenvironment. The toxicity of CS-ZnO BNCs and ZnO-NPs against the MDA-M-231 BCCs was evaluated using MTT-colorimetric assay, which demonstrated superior biocompatibility of CS-ZnO BNCs compared to pure ZnO-NPs (even at high concentration of 100 μg/mL). Survival fraction analysis of cells under clinical X-ray irradiation (6 MV) showed that MCTSs had a higher radioresistance compared to parental cells. Besides, the clonogenic potential of irradiated MCTSs was significantly decreased by the addition of CS-ZnO BNCs similar to that of monolayer cells. The sensitivity enhancement ratios (SER) for MCTSs and monolayer cells were calculated 1.5 and 1.63, respectively. Further, tracking of radiobiological properties and apoptosis induction of MCTSs showed that CS-ZnO BNCs not only could lead to the creation of higher radiation-induced complex DNA break and apoptosis death in MCTSs, but also weakened DNA repair mechanisms. It was found that non-toxic concentration of CS-ZnO BNCs has promising potential to enhance radiosensitivity of resistant-MCTSs as a superior in-vitro tumor model. So, CS-ZnO BNCs can be a prominent candidate for overcoming the resistance of BCCs to radiotherapy.

Biocompatible chitosan-zinc oxide nanocomposite based dispersive micro-solid phase extraction coupled with HPLC-UV for the determination of rosmarinic acid in the extracts of medical plants and water sample

In the present research, a procedure was described for the recovery of rosmarinic acid (RA) from medical extract samples using chitosan‑zinc oxide nanoparticles as a biocompatible nanocomposite (CS-ZnO-NC). The dispersive micro-solid phase extraction (D-μ-SPE) of RA from the medical extract samples was investigated by using the prepared biocompatible composite as a solid phase. The HPLC-UV method was used for measuring the extracted RA. The important variables (pH, biocompatible composite mass, contact time, and volume of eluent) associated with the extraction process were analyzed by the application of central composite design (CCD). The achieved optimum values for the mentioned variables were 7.0, 10 mg, 4 min, and 180 μL, respectively. The extraction recovery (99.68%) obtained from the predicted model was in agreement with the experimental data (98.22 ± 1.33%). In addition, under the obtained optimum conditions and over the concentration in the range of 2-3500 ng mL-1, a linear calibration curve was obtained with R2 > 0.993. The limit of detection (LOD) and quantification (LOQ) values were computed, and the obtained ranges were respectively from 0.060 to 0.089 ng mL-1 and 0.201 to 0.297 ng mL-1. In addition, the enrichment factors were obtained in the range of 93.7-110.5 with preconcentration factor of 83.3. Therefore, the D-μ-SPE-HPLC-UV method could be used for analyzing RA in the samples of the extracts obtained from the medical plants and water with the recovery values of the analyte in the range of 96.6%-105.4% and the precision with relative standard deviation <5.7%.

Combined Effect of Iodine Contrast Media, Cisplatin and External Beam Radiotherapy on Anaplastic Thyroid Cancer Cells

INTRODUCTION

The current study investigated the combination of high Z atoms (iodine-, platinium-based drugs) with using low energy irradiation (120kvp) in Anaplastic Thyroid cancer cells.

MATERIAL AND METHODS

For this purpose, eight groups were designed: control (CNT), different concentrations of Iodine contrast media (ICM), irradiation with various doses, Cis-platin (CDDP) with different concentrations, (ICM + CDDP), (ICM + RAD), (CDDP + RAD) and (ICM + CDDP + RAD). The viability was measured by MTT and Colony assay. In MTT assay, the viability of 8305c cells RAD (2 Gy)+ICM (10mg/mL) group was significantly lower than those treated with RAD or ICM alone. CDDP +ICM+RAD group significantly decreased the viability. In colony assay, cells in ICM + RAD (2 Gy) group reduced the number of colonies more significant than RAD group. The difference of colony forming ability between CDDP and CDDP + RAD (2 Gy) was significant. The difference of ICM + CDDP + RAD (2 Gy) and CDDP +RAD (2 Gy) group was significant. All data were statistically analysed using one-way analysis of variance (ANOVA) followed by Chafe's multi-comparisons tests. All data were presented as mean ± standard deviation (SD) and analysed using statistical package for social sciences (SPSS 16). Significance was considered to be p<0.05.

RESULTS

In MTT assay, the viability of 8305c cells RAD (2 Gy) + ICM (10mg/mL) group was significantly lower than those treated with RAD or ICM alone. CDDP + ICM + RAD group significantly decreased the viability. In colony assay, cells in ICM + RAD (2 Gy) group reduced the number of colonies more significantly than RAD group. The difference of colony forming ability between CDDP and CDDP + RAD (2 Gy) was significant. The difference of ICM + CDDP + RAD (2 Gy) and CDDP + RAD (2 Gy) group was significant.

CONCLUSION

Exposure of ATC to ICM in the presence of CDDP increases tissue X-rays absorbance by Auger electrons and photo electrons leading to more fatal effects against the tumour.

Comparative evaluation of antimicrobial activity of two root canal sealers: MTA Fillapex and AH 26

AIM

Even after a complete root canal therapy, reinfection may occur as a result of incomplete seal and activation of residual bacteria. Thus, antimicrobial activity is an important characteristic of root canal sealers. MTA Fillapex is a newly developed MTA-based sealer. It has been subjected to various studies evaluating its physical and chemical properties. In this study, we aimed to compare the antimicrobial activity of this sealer to the commonly known widely accepted sealer, AH26.

METHODS

MTA Fillapex and AH 26 were exposed the bacterial suspension of Enterococcus faecalis, Escherichia coli, Streptococcus mutans, and Candida albicans after setting. After incubation and complete evaporation, BHI was added to microtubes. 24 hours later, the liquid content was placed in agar diffusion plate and bacterial count was performed. ANOVA followed by Tukey test, and t-Test were performed to analyze the data.

RESULTS

With regard to all four bacterial groups, the bacterial count was significantly lower in MTAFillapex group comparing to AH 26 group.

CONCLUSION

Newly developed MTA Fillapex sealer, has better antimicrobial properties in comparison to the widely accepted AH26 sealer.