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 ...
Pharmacological Inhibition of Mammalian Target of Rapamycin Attenuates Deoxycorticosterone Acetate Salt–Induced Hypertension and Related Pathophysiology: Regulation of Oxidative Stress, Inflammation, and Cardiovascular Hypertrophy in Male Rats
Temiz Reşitoğlu, Meryem | Sucu, Nehir | Kibar, Deniz | Yılmaz, Şakir Necat | Tunçtan, Bahar | Şahan Fırat, Seyhan
The present study aimed to explore the contribution of mammalian target of rapamycin (mTOR) in deoxycorticosterone acetate (DOCA) salt–induced hypertension and related pathophysiological changes in cardiovascular and renal tissues. DOCA salt loading resulted in an increase in systolic blood pressure, diastolic blood pressure, and mean blood pressure along with the activity of ribosomal protein S6, the effector protein of mTOR. Treatment with rapamycin, the selective inhibitor of mTOR, initiated at the fourth week of DOCA- salt administration normalized the systolic blood pressure and attenuated ribosomal protein S6 activity in the heart, aorta, and kidney. Cardiac and vascular hypertrophy, oxidative stress, and infiltration of macrophages (CD68+), the marker of inflammation, were also redu...
mTOR inhibition as a possible pharmacological target in the management of systemic inflammatory response and associated neuroinflammation by lipopolysaccharide challenge in rats
Temiz Reşitoğlu, Meryem | Kibar, Deniz | Yılmaz, Şakir Necat | Tunçtan, Bahar | Şahan Fırat, Seyhan
Neuroinflammation plays a critical role during sepsis triggered by microglial activation. Mammalian target of rapamycin (mTOR) has gained attraction in neuroinflammation, however, the mechanism remains unclear. Our goal was to assess the effects of mTOR inhibition by rapamycin on inflammation, microglial activation, oxidative stress, and apoptosis associated with the changes in the inhibitor-κB (IκB)-α/nuclear factor-κB (NF-κB)/hypoxia-inducible factor-1α (HIF-1α) pathway activity following a systemic challenge with lipopolysaccharide (LPS). Rats received saline (10 mL/kg), LPS (10 mg/kg), and (or) rapamycin (1 mg/kg) intraperitoneally. Inhibition of mTOR by rapamycin blocked phosphorylated form of ribosomal protein S6, NF-κB p65 activity by increasing degradation of IκB-α in parallel with...
Evaluation of the effect of resveratrol on bone healing after tooth extraction in rats treated with zoledronic acid
Kucuk, Ayse Ozcan | Ak, Burak | Yılmaz, Şakir Necat | Kibar, Deniz | Gök, Ayşe Betül
This study aimed to evaluate the potential use of resveratrol on bone healing after tooth extraction in zoledronic acid-treated rats. Seventy-two Wistar rats were separated into 4 groups of 18: no drugs (control group), zoledronic acid (ZA), resveratrol (RES), zoledronic acid + resveratrol (ZA + RES). The first and second molars of each rat were extracted and nine rats from each group were sacrificed on days 14 and 28. The extraction sites and blood samples were analyzed histologically, immunohistochemically and biochemically. The epithelization, connective tissue, new bone formation in RES group was significantly higher compared to ZA and ZA + RES groups on day 28. The connective tissue in control group was significantly higher compared to ZA and ZA + RES groups on days 14 and 28. BMP-4 l...
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...
Study and development of electrospun (TPU, PA-6) / silicone bilayer membranes for congenital diaphragmatic hernia repair
Bölgen, Nimet | Yılmaz, Şakir Necat | Kibar, Deniz
Large defects in the congenital diaphragmatic hernia (CDH) are treated by prosthetic materials, most frequently polytetrafluoroethylene (PTFE), with high complications. The purpose of this study is to develop a novel electrospun double-faced prosthesis that will minimize these surgical complications. Polyamide 6 (PA-6) and thermoplastic polyurethane (TPU) nanofibers were prepared by solution electrospinning, and room temperature vulcanized silicone (RTV) was used in electrospinning by dip-coating to develop a double-faced membrane. The results demonstrate that the duration of electrospinning and thickness of silicone layers influence the morphology of the bilayer scaffolds. Electrospun bilayer polyamide 6/silicone and thermoplastic polyurethane/silicone scaffolds are fabricated as potentia...
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...