In vivo protective efficacy of astaxanthin against ionizing radiation-induced DNA damage

Astaxanthin, a carotenoid pigment, is believed to be effective in the repair of DNA damage. Our study evaluates the effect of astaxanthin on DNA damage in rats exposed to whole-body radiotherapy using the comet assay. Thirty-two male rats were randomly divided into four groups (control, ionizing radiation, astaxanthin, and radiation+astaxanthin). The radiation and radiation+astaxanthin groups were exposed to X-rays at a dose of 8 gray (0.62 gray/min). Astaxanthin was administered at 4 mg/kg by gavage for 7 days starting from irradiation. The %TailDNA parameter was chosen as an indicator of DNA damage and the results were compared using one-way ANOVA. %TailDNA was 3.24 ± 3.12 in the control group, 2.85 ± 2.73 in the astaxanthin group, 4.11 ± 7.90 in the radiation group, and 3.59 ± 4.05 in the radiation+astaxanthin group. There was a significant increase in DNA damage in the radiation group, compared with the control and astaxanthin groups (p < .001). DNA damage was reduced in the radiation+astaxanthin group compared with the radiation group (p < .05). Although this decrease did not reduce damage to the level of the control group, it was significant. The decrease in radiation-induced DNA damage by astaxanthin administration in our study supports the hypothesis that astaxanthin is a promising agent for against/reducing DNA damage.

Apoptotic effects of Phlomis armeniaca mediated biosynthesized silver nanoparticles in monolayer (2D) and spheroid (3D) cultures of human breast cancer cell lines

The purpose of current research was to assess the apoptotic effects of biofabrication silver nanoparticles (AgNPs) mediated by the aqueous extract of Phlomis armeniaca on human breast cancer cells (MCF-7 and MDA-MB-231) in monolayer (2D) and spheroid (3D) cultures. The biosynthesized AgNPs were characterized by UV-Vis spectrophotometer (the peaks of resonances at 432 nm), scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDS). 1-20 µM/mL AgNPs were applied to MCF-7 and MDA-MB-231 cell lines to determine IC50 values at 24, 48 and 72nd h and were found to be 10 µM/mL for both cell lines. Immunohistochemical staining results of BrdU, TUNEL, caspase-3 and Endo G in both 2D and 3D cultures and gene expression levels of caspases (caspase-3, -8 and -9) and Endo G were evaluated. Moreover, the total oxidant/antioxidant status (TOS-TAS) due to AgNPs application in both cell culture mediums was evaluated. AgNPs treatment results in both cell lines in both 2D and 3D cultures showed a significant decrease in the BrdU labeling index, while large amounts of cells were labelled with TUNEL and Endo G. In 2D culture, Endo G expression increased in MCF-7 cells at 48 and 72nd hours, while it increased significantly in MDA-MB-231 cells at all hours. OSI results show that ROS production is increased in cell medium treated with AgNPs. In conclusion, AgNPs mediated by Phlomis armeniaca, synthesized by a green method, successfully induced damage to mitochondria, resulting in cell cycle arrest and consequent cell proliferation blockade and death in both MCF-7 and MDA-MB-231 cells.

Genotoxicity of thiacloprid in zebrafish liver

Thiacloprid (TH), one of the most widely used pesticides in the world, might cause toxic effects like DNA damage in humans and animals due to their frequent use. Accordingly, this study investigated TH's potential DNA-damaging effects on zebrafish liver via alkaline comet assay. Two treatment groups of ten zebrafish each were exposed to TH at two different concentrations, 1.64 and 0.82 mg/L, for 21 days and compared with an untreated control group. After exposure, the fishes' liver tissues were excised, and an alkaline comet assay was performed. Two slides per sample and 50 cells per slide were assessed with a visual evaluation program. The average DNA Damage values of the control, 0.82 mg/L TH, and 1.64 mg/L TH groups were 4.37 ± 5.12, 8.51 ± 8.54, and 9.30 ± 9.99, respectively. Both TH treatment groups had statistically significantly more DNA damage than the control group (p < 0.001). When comparing the TH treatment groups alone, the 1.64 mg/L dose group featured greater damage than the 0.82 mg/L dose group (p < 0.05). TH therefore causes significant DNA damage to the liver in a dose-dependent manner, revealing it to be a genotoxic agent that should be further investigated.

Lymphocyte DNA damage in sepsis and septic-shock intensive-care patients: Damage is greater in non-intubated patients

Sepsis is an excessive host response to infection; septic shock is a more severe clinical condition. We studied 43 sepsis patients, 32 septic-shock patients, and a group of healthy controls. The patients' Sequential Organ Failure Assessment (SOFA) and Acute Physiology and Chronic Health Evaluation (APACHE) 2 score were much higher in the septic-shock group than in the sepsis group. We used the comet assay to measure lymphocyte DNA damage; the damage scores were significantly higher in both the sepsis and the septic-shock groups compared to the healthy controls. There was no statistically significant difference between the sepsis and septic-shock groups. We also compared DNA damage levels of intubated vs. non-intubated patients. DNA damage was significantly higher in non-intubated patients compared to intubated patients, for both the sepsis and the septic-shock groups. Early intubation may be beneficial in non-intubated patients who have high levels of DNA damage.

Hypothalamic NR3C1 DNA methylation in rats exposed to prenatal stress

BACKGROUND

Human and animal studies have indicated that maternal prenatal stress (PS) has molecular and behavioral effects during pregnancy and early life. The present study aimed to evaluate the epigenetic changes of the NR3C1 gene involved in the HPA axis in the hypothalamic tissues of rats exposed to PS induced by chronic unpredictable mild stress (CUMS). Behavioral and molecular effects of these changes on the next generation were also assessed.

METHODS AND RESULTS

CUMS protocol was used to generate stress in pregnant Wistar rats. To determine the effects of stress on anhedonia and movement, sucrose preference test, forced swimming test, and open field test were performed. Following these behavioral experiments, bisulfite sequencing PCR for DNA methylation levels of the NR3C1 gene, RT-qPCR for mRNA levels, and Western blot techniques for protein analysis were used in the hypothalamic tissue of sacrificed rats. Depression-like behaviors were evident in the behavioral tests of stress-exposed mothers and pups. In PS-exposed pups, hypothalamic NR3C1 promoter methylation was higher, and NR3C1 mRNA levels and NR3C1 protein levels were lower compared with controls, regardless of sex.

CONCLUSION

Our results confirm the relationship between PS and epigenetic changes of HPA axis-related genes and show that NR3C1 gene methylation status in pups is sensitive to PS during pregnancy. Environmental maternal stress may have transgenerational effects that are potentially associated with adverse outcomes in the pups.

Secoisolariciresinol diglucoside induces caspase-3-mediated apoptosis in monolayer and spheroid cultures of human colon carcinoma cells

Apoptotic effects of secoisolariciresinol diglucoside (SDG) in 2D and 3D cultures of SW480 cells were investigated. 40-200 μM SDG was used and IC50 values were determined for three different time intervals as 24, 48, or 72 hr for further experiments. BrdU, TUNEL, AIF, and caspase-3 stainings were used. SDG inhibited cell proliferation almost half and half for all time intervals in 2D and 3D cultures and also, induced apoptosis. Apoptotic cell percentages in the control group for 24, 48, and 72 hr were 27.00%, 29.00%, and 28.00%, respectively, while in the SDG treatment group were 59.00%, 61.00%, and 62.00%, respectively. In the spheroid cell culture, apoptotic cell percentages in the control group for 24, 48, and 72 hr were 6.90%, 7.20%, and 7.10%, respectively, while in the SDG treatment group were 19.50%, 19.50%, and 20.70%, respectively. Caspase-3 and AIF antibodies were used to indicate caspase-dependent and -independent apoptotic pathways. Significant increases were seen in both AIF and caspase-3 stainings when compared to the control group but caspase-3 staining results were significantly greater when compared to the AIF staining at all time intervals (p < .05). To prove this, CASP3 gene expression was evaluated by RT-qPCR. Unlike staining results, there was no statistically significant change at 24 hr in 2D and 3D cultures. But, significant upregulation at 48 (2.32-fold in 2D and 2.46-fold in 3D) and 72 hr (5.04-fold in 2D and 6.45-fold in 3D) were seen. PRACTICAL APPLICATIONS: Colon cancer is one of the most prevalent cancer in the developed countries and its etiology is complex. Although the underlying mechanisms are mostly unknown, the link between diet and colon cancer is known and dietary habits can promote cancer or protect against it. In recent years, flaxseed is accepted as a significant functional food ingredient and feeding with it could help in to prevent cancer. Secoisolariciresinol diglucoside is a flaxseed lignan and is metabolized to mammalian lignans by the gut. In the present study, SDG was evaluated for its apoptotic effects in colon carcinoma cell line via monolayer and spheroid cultures using immunohistochemical and gene expression techniques. Findings of this study suggest that SDG may protect against cancers and in particularly against colon cancer and further investigations has to be carried out for detailed underlying mechanisms.

DNA damage effect of cyprodinil and thiacloprid in adult zebrafish gills

Cyprodinil and thiacloprid are two of the most commonly used pesticides in Turkey. It is more likely to reach humans or animals due to their widespread use. This study aims to investigate whether there is a DNA damage risk due to cyprodinil and thiacloprid exposure. Zebrafish, which is used as a model organism in health and environmental research, and comet assay were chosen to demonstrate this damage. Ten zebrafish per group were exposed to 2 different concentrations for each pesticides (0.31 and 0.155 mg/L for cyprodinil and 1.64 and 0.82 mg/L for thiacloprid) for 21 days. After, gills were excised and comet assay was performed. Photos of an average of 50 cells per slide were taken and were analyzed with visual evaluation program. DNA damage was found to be increased in the 0.31 mg/L cyprodinil, 0.82 mg/L thiacloprid, and 1.64 mg/L thiacloprid treatment groups when compared to the control group (p < 0.001). Average tail DNA percentage parameter values were 9.45 ± 0.51, 10.30 ± 0.34, 11.17 ± 0.33, and 2.47 ± 0.06 respectively. Cyprodinil and thiacloprid were identified as genotoxic agents that should be investigated further.