Cytotoxic effect of silica nanoparticles on human retinal pigment epithelial cells
Çömelekoğlu, Ülkü | Kibar, Deniz | Yıldırımcan, Saadet | Yılmaz, Şakir Necat
In recent years, the use of nanotechnology-based methods has become widespread in the treatment of ocular diseases. Silica nanoparticles (SiO2 NPs) are most common used NPs in medical field due to their physicochemical properties. SiO2 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 SiO2 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 mg/mL SiO2, 100 mg/mL SiO2 and 150 mg/mL SiO2 groups. Cell index, apoptotic activity, cell cycle and ...
Ameliorative effects of paricalcitol against 1800-MHz mobile phone radiation-induced skin damage in rats
Aktaş, Savaş | Çömelekoğlu, Ülkü | Demirbağ, Burcu | Kibar, Deniz | Söğüt, Fatma | Yalın, Serap
This study aimed to evaluate the protective role of paricalcitol, a vitamin D analog, against hazardous effects of 1800-MHz radiofrequency (RF) radiation on the skin of male Wistar albino rats exposed one h/day for 4 weeks. The maximum specific absorption rate was calculated as 0.0042 W/kg. Superoxide dismutase and catalase activity, collagen bundle thickness, breaking force, energy, and stress were decreased, while malondialdehyde level and mast cell number were increased. The exposure to 1800-MHz RF radiation caused a reduction in skin biomechanical quality through oxidative stress and mast cell activation. The administration of paricalcitol caused a significant improvement.
N -Acetylcysteine-induced vasodilatation is modulated by K ATP channels, Na /K -ATPase activity and intracellular calcium concentration: An in vitro study
Çömelekoğlu, Ülkü | Sucu, Nehir | Yalın, Ali Erdinç | Yılmaz, Şakir Necat | Yalın, Serap | Söğüt, Fatma | Kibar, Kezban | Akkapulu, Merih
Background In this study, we aimed to investigate the role of ATP-sensitive potassium (KATP) channel, Na+/K+-ATPase activity, and intracellular calcium levels on the vasodilatory effect of N-acetylcysteine (NAC) in thoracic aorta by using electrophysiological and molecular techniques. Methods Rat thoracic aorta ring preparations and cultured thoracic aorta cells were divided into four groups as control, 2 mM NAC, 5 mM NAC, and 10 mM NAC. Thoracic aorta rings were isolated from rats for measurements of relaxation responses and Na+/K+-ATPase activity. In the cultured thoracic aorta cells, we measured the currents of KATP channel, the concentration of intracellular calcium and mRNA expression level of KATP channel subunits (KCNJ8, KCNJ11, ABCC8 and ABCC9). Results The relaxation rate sig...
Investigation of the role of KATP channels in the cytotoxic effect of cypermethrin on rat-derived aortic smooth muscle cells
Söğüt, Fatma | Kibar, Deniz | Çömelekoğlu, Ülkü
We investigate role of atP sensitive potassium (KatP) channel in cytotoxic effect of cypermethrin on rataortic smooth muscle cells. cytotoxicity analysis was performed at 0, 0.1, 0.5, 10, 50, and 100 µMconcentrations of cypermethrin and the cell index (ci) was calculated. KatP currents were recorded usingpatch clamp technique for 50 and 100 µM concentrations and channel conductivity was determined byobtaining current-voltage characteristics. No cytotoxic effect was observed in the first 72 hours. at the96th hour, only at 100 µM concentration, the ci value decreased significantly compared to control groupand at 120 and 144th hours, it was observed that the ci value decreased significantly at all concentrations.currents and conductivities were significantly decreased at 50 and 100 µM concent...
Determination of the effect of silica nanoparticles on TRP currents in retinal pigment epithelial cells by entropy measurement
Söğüt, Fatma | Kibar, Deniz | Yılmaz, Şakir Necat | Çömelekoğlu, Ülkü
Ion channels in cell membranes are gated, water-filled pores that allow passive transport of ions across the membrane along their electrochemical gradient. Recent studies have shown that nanoparticles can interact with ion channels and change their currents kinetics properties of the channel. In this study, we used the transient receptor potential (TRP) channel currents in retinal pigment epithelial (RPE) cells recorded by whole-cell patch clamp technique to observe the silica nanoparticle-ion channel interaction. For whole cell recordings, we clamped membrane potential to −40 mV and used a ramp of 1000 ms duration for stimulation. The ramp was increased from −140 mV to +60 mV. We used windowed scalogram entropy and compared the results with windowed scale index method. Our results indicat...