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In recent years, the use of nanotechnology-based methods has become widespread in the treatment of ocular diseases. Silica nanoparticles (SiO 2 NPs) are most common used NPs in medical field due to their physicochemical properties. SiO 2 NPs can easily cross biological membranes and interact with basic biological structures, causing structural and functional changes in cells. In this study, it was aimed to investigate the dose dependent effect of SiO 2 NPs on retinal pigment epithelium (RPE) in vitro using electrobiophysical, biochemical and histological methods. A commercially purchased human RPE (hARPE-19) cell line was used in this study. Cells were divided into four groups as control, 50 μg/mL SiO 2 , 100 μg/mL SiO 2 and 150 μg/mL SiO 2 groups. Cell index, apoptotic activity, cell cycle and oxidative stress markers were measured in all groups. Findings in the present study showed that SiO 2 nanoparticles reduced cell proliferation, increased oxidative stress, apoptosis and arrest in the G 0 /G 1 phase of the cell cycle as dose dependent manner in ARPE-19 cells. In conclusion, SiO 2 exposure can induce cytotoxic effects in RPE cell line. The results of this study provide clues that exposure to SiO 2 nanoparticles may impair visual function and reduce quality of life. However, further studies are needed in this regard. • SiO 2 nanoparticles are used as drug carriers in the treatment of many eye diseases. • SiO 2 nanoparticles have toxic effects that should not be ignored. • SiO 2 nanoparticles reduce cell proliferation in hARPE19 cells. • SiO 2 nanoparticles induce apoptosis and Go/G1 arrest in hARPE19 cells. • SiO 2 nanoparticles cause induce oxidative stress leading to cell death in hARPE19 cells. [ABSTRACT FROM AUTHOR]

Rapid development in mobile phone technologies increase the average mobile phone usage duration. This increase also triggers exposure to radiofrequency radiation (RF), which is a risk factor for the health. In this study, it was aimed to investigate the effect of mobile phone working with LTE-Advanced Pro (4.5 G) mobile network on the optic nerve, which is responsible for the transmission of visual information. Thirty-two rats divided into two groups as control (no RF, sham exposure) and experimental (RF exposure using a mobile phone with LTE-Advanced Pro network; 2 hours/day, 6 weeks). The visual evoked potential (VEP) was recorded and determined amplitudes and latencies of VEP waves. Optic nerve malondialdehyde level, catalase and superoxide dismutase activities were determined. Furthermore, ultrastructural and morphometric changes of optic nerve were evaluated. In VEP recordings, the mean VEP amplitudes of experimental group were significantly lower than control group. In ultrastructural evaluation, myelinated nerve fibres and glial cells were observed in normal histologic appearance both in sham and experimental group. However, by performing morphometric analysis, in the experimental group, axonal diameter and myelin thickness were shown to be lower and the G-ratio was higher than in the sham group. In the experimental group, malondialdehyde level was significantly higher and superoxide dismutase and catalase activities were significantly lower than sham group. There was a high correlation between VEP wave amplitudes and oxidative stress markers. Findings obtained in this study support optic nerve damage. These results point out an important risk that may decrease the quality of life. [ABSTRACT FROM AUTHOR]

Silica is among the most popular nanoparticles. Large-scale production and use have increased the risk of human exposure to silica nanoparticles (SiO2NPs). This study aimed to investigate the toxic effects on the kidney, liver and brain of the SiO2NPs. Twenty eight male Wistar albino rats were divided into four groups (n=7 rats) as control (1 mL/day physiological saline administration for 28 day), 6 nm SiO2NP (6 nm, 150 μg/mL/day for 28 day), 20 nm SiO2NP (20 nm, 150 μg/mL/day for 28 day) and 50 nm SiO2NP (50 nm, 150 μg/mL/day for 28 day) groups. After the last administration, rats were sacrificed and kidney, liver and brain samples were taken for biochemical and histological investigation. In all groups, malondialdehyde (MDA) levels, superoxide dismutase (SOD) and catalase (CAT) activities were measured using the spectrophotometric methods. Ultrastructural changes of tissues were evaluated using transmission electron microscopy. In the kidney tissue, the MDA level significantly increased in the 6 and 50 nm groups, while the similar increase was observed in the 6 nm group of the liver and 20 and 50 nm groups of the brain. SOD activity significantly increased in the 6, 20 and 50 nm groups in brain and kidney tissues, but no significant change was observed in the liver tissue groups. Catalase activity decreased in the kidneys at 6 and 50 nm groups and increased in the 20 and 50 nm groups in liver and brain tissues. Ultrastructurally, kidney and liver tissues had normal morphological features in all groups. Degenerative changes were observed in the nerve fibers and axoplasm of myelinated and unmyelinated nerve fibers in 6 nM, 20 nM and 50 nM SiO2NP groups in the brain. These findings showed that exposure to 6, 20 and 50 nm sizes SiO2 NPs may cause toxic effects in the liver, kidney and brain. [ABSTRACT FROM AUTHOR]

In spite of their widespread use, toxicity of silica nanoparticles (SiO2 NPs) to mammalian has not been extensively investigated. In the present study, it is aimed to investigate the effects and the mechanism of action of 20 nm sized SiO2 NPs on isolated uterine smooth muscle. A total number of 84 preparations of uterine strips were used in the experiments. Study was designed as four groups: group I (control), group II (0.2 mM SiO2 NPs), group III (0.4 mM SiO2 NPs) and group IV (0.8 mM SiO2 NPs). Spontaneous contractions were recorded using mechanical activity recording system. Superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities and malondialdehyde (MDA) levels were measured using the spectrophotometric methods. Apoptosis of the cells was detected using immunofluorescence staining assay. SiO2 NP distribution and ultrastructural changes were determined by transmission electron microscopy. In groups II-IV, the frequency of contraction was significantly lower than that of the group I, whereas the contraction energy significantly decreased only in group IV. SOD and GSH-Px activities were significantly lower in experimental groups compared to the control group. MDA level and apoptotic cells were significantly higher in all SiO2 groups compared to the control group. Numerous SiO2 NPs in cytoplasm and connective tissue were observed in all dose groups. These findings showed that 20 nm sized SiO2 NPs enter the connective tissue and cytoplasm of uterine muscle cells and cause oxidative stress and apoptosis leading to impaired uterine contractile activity. [ABSTRACT FROM AUTHOR]

Radio-frequency electromagnetic radiation (RF-EMR) represents one of the environmental factor that influence animal organism to stress. In this study we determined the oxidative stress parameters from rat liver, kidney and brain tissues that were exposed to chronic 1800 MHz RF-EMR. Our study was designed in 3 groups as 9 animals in each group. These are; control, sham and RF-EMR exposed group. The control group was not exposed to any procedure; sham group was housed in the same room under the same conditions with equal time period, except that the generator was turned off. RF-EMR exposed group was subjected to 1800 MHz RF-EMR emitted from the signal generator for 2 h per day for eight weeks. All animals that completed the experimental period were sacrificed and liver, kidney and brain tissues of all rats were isolated for analyzing malondialdehyde (MDA), nitric oxide (NO) and reduced glutathione (GSH) levels and superoxide dismutase (SOD) and catalase activities. Liver, kidney and brain MDA and NO levels were higher and GSH level and SOD and catalase activities were significantly lower in RF-exposed group than control and sham groups (p<0.001). No significant difference was observed in terms of tissue MDA, GSH and NO levels and SOD and catalase activities between control and sham groups in each tissue. The results of our study shows that RF-EMR may act as an environmental stressor and cause oxidative and nitrosative damage in liver, kidney and brain tissues. [ABSTRACT FROM AUTHOR]

Strontium ranelate is one of the most common post-menopausal osteoporosis medications that have been used in recent years. The effects of strontium ranelate treatment on the free radical-antioxidant balance of the skin have not been fully elucidated. In this study, we investigated the effects of strontium ranelate treatment on oxidative stress parameters in the skin tissue of rats with the experimental osteoporosis model. Total 35 rats were divided to five groups as control group (Group I), oophorectomy group (Group II), strontium ranelate group (Group III), oophorectomy + strontium ranelate group (immediately after the oophorectomy) (Group IV) and oophorectomy + strontium ranelat group (after three months of oophorectomy) (Group V). In Group III, IV and V, 500 mg/kg doses of strontium were given to rats by orally. At the end of the study, superoxide dismutase (SOD) and catalase activities, malondialdehyde (MDA) and glutathione (GSH) levels of the rats' skin tissues were determined. Catalase and SOD activities and GSH levels of all groups were significantly lower than Group I (p<0.05). MDA levels of all groups were significantly higher than Group I (p<0.05). Catalase and SOD activities and GSH levels of Group IV and V were significantly lower than Group II (p<0.05). MDA levels of Group IV and V were significantly higher than Group II (p<0.05). In conclusion, strontium ranelate treatment in oophorectomized rats has resulted in an increase in oxidative stress in skin tissue and can cause to several skin disorders. [ABSTRACT FROM AUTHOR]

Aim: To investigate the effect of ovariectomy on the skin using biomechanical, biochemical, and histological techniques in the ovariectomized rat model. Ovariectomy causes significant changes in the physical characteristics of the skin. Materials and methods: Twenty female Wistar albino rats were divided into 2 groups, with each group consisting of 10 rats: the control group and the ovariectomized group. The ovariectomized group underwent bilateral ovariectomy via ventral incision and the control group underwent a sham operation. Skin biomechanics were measured 3 months following the ovariectomy with a tensile test using a biomaterial testing machine, and tensile strength, stress, strain, and toughness were calculated. Superoxide dismutase (SOD) and catalase (CAT) activities and the levels of malondialdehyde (MDA) in the skin of the rats were also measured using the biochemical methods. Thickness of the epidermis was determined by light microscopy. Results: Strength, stress, strain, SOD activity, and thickness of epidermis values were significantly decreased and the MDA level was increased in the ovariectomized rats compared to the control group. Conclusion: Our results showed that ovariectomy decreased the biomechanical quality of skin. This result may be related to reactive oxygen species generated by the induction of ovariectomy in rat skin damaging the connective tissue components of the dermis. [ABSTRACT FROM AUTHOR]