PubMed İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.14627/8
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Article Protective Effects of L-Theanine against Bisphenol A-Induced Oxidative Stress and Gut Microbiota Disruption in Wistar Rats(Springer, 2026) Sener, Azize; Marzi, Mahdi; Sener, Goksel; Donmez, Muhammet OguzhanBackground Gut microbiota homeostasis plays a central role in maintaining intestinal redox balance and immune regulation. Bisphenol A (BPA), a widely distributed environmental contaminant, has been associated with oxidative stress, inflammatory responses, and disturbances in intestinal microbial communities. L-theanine (LTN), a bioactive amino acid naturally present in green tea, possesses well-documented antioxidant and anti-inflammatory properties; however, its potential protective role against BPA-induced intestinal injury has not been fully clarified. Methods and Results In the present study, female Wistar albino rats were randomly allocated into three groups: control, BPA (50 mg/kg/day), and BPA + LTN (100 mg/kg/day) and treated for 30 days. Oxidative stress and inflammatory responses in intestinal and colonic tissues were assessed by measuring malondialdehyde (MDA), reduced glutathione (GSH) levels and myeloperoxidase (MPO), catalase (CAT) activities. BPA exposure significantly increased MDA (p < 0.001) level and MPO (p < 0.001) activity while reducing GSH content (p < 0.001) and CAT activity (p < 0.001) compared with the control group. Compared to the BPA group, LTN treatment led to significant changes in MDA, MPO, and GSH levels in both tissues. MDA and MPO levels were significantly reduced in the intestine and colon tissues of the BPA + LTN group (p < 0.001). GSH and CAT levels were significantly increased in both the intestine and colon compared to the BPA group (p < 0.001). In addition, fecal microbiota composition was analyzed using 16 S rRNA gene sequencing, with taxonomic profiling performed at the phylum, genus and species levels. BPA exposure was associated with reduced microbial stability and compositional shifts within the gut microbiota, whereas LTN treatment partially restored microbial richness and community structure. Conclusions Collectively, these findings indicate that LTN alleviates BPA-induced intestinal oxidative stress and microbiota dysbiosis, suggesting its potential as a protective dietary compound against environmental toxicant-related intestinal injury.Article Modulation of Brain Antioxidant Defense, Inflammation, and SIRT1 Activity by a Sunflower Oil-Based High-Fat Diet: Protective Role of L-Arginine in Rats(Springer, 2026) Şekerler, Turgut; Şener, Azize; Çavuşoğlu, Nuray; Doğan, ÖzgeBackgroundChronic consumption of omega-6-enriched dietary fat may disturb brain redox balance and neuroinflammatory homeostasis. Among the sirtuins, sirtuin 1 (SIRT1) exerts critical neuroprotective functions by suppressing oxidative stress and inflammatory signaling; however, the impact of sunflower oil-based high-fat diets (SO-HFD) on brain SIRT1 activity has not been investigated.ObjectiveThis study aimed to investigate the effects of SO-HFD on oxidative stress parameters, inflammatory markers, and SIRT1 activity in rat brain tissue, and to evaluate the potential modulatory role of L-arginine supplementation.MethodsFour-week-old female Sprague-Dawley rats were allocated into three groups: control, SO-HFD, and SO-HFD + L-arginine. Both SO-HFD groups were fed a diet containing sunflower oil for 16 weeks; from week 10 onward, 1.5% L-arginine was supplemented in the drinking water of the SO-HFD + L-arginine group. Following the 16-week protocol, serum and brain specimens were collected. Serum biochemical parameters and adiponectin were quantified; brain homogenates were assayed for lipid peroxidation (MDA), reduced glutathione (GSH), protein thiols (protein-SH), nitric oxide (NO), tumor necrosis factor-alpha (TNF-alpha) levels, and SIRT1 activity.ResultsAlthough brain MDA levels were not significantly elevated, SO-HFD animals exhibited reduced GSH and protein-SH content together with diminished SIRT1 activity. The SO-HFD increased TNF-alpha and NO levels. L-arginine supplementation decreased MDA and increased GSH, protein-SH, and SIRT1 activity. L-arginine also suppressed TNF-alpha levels in brain tissue compared to the SO-HFD group. NO levels in the SO-HFD + L-arginine group were lower than in the SO-HFD group, though not significantly.ConclusionThese findings suggest that chronic exposure to an omega-6-dominant dietary environment disturbs redox regulation and inflammatory balance in brain tissue, accompanied by reduced SIRT1 activity. L-arginine may attenuate cerebral oxidative stress and neuroinflammation by reinforcing endogenous antioxidant mechanisms, highlighting its potential as a nutritional strategy against SO-HFD-induced brain oxidative stress.Article Citation - WoS: 2Citation - Scopus: 3Petroselinum Crispum Extract Prevents Scopolamine-Induced Lens Damage in Rats(Wiley-v C H verlag Gmbh, 2023) Ertik, Onur; Pazarbasi, Seren Ede; Sener, Goksel; Sacan, Ozlem; Yanardag, RefiyeAlzheimer's disease (AD) is a neurodegenerative disease that occurs especially in advanced ages. It reduces the quality of life of both the patient and their relatives. In addition to its primary effects, AD causes metabolic defects and tissues are damaged due to these effects. Oxidative stress damages cells by disrupting antioxidant/oxidant balance in many tissues, especially due to AD. In individuals with AD and the elderly, lens tissue is damaged due to oxidative stress and may cause vision loss. Therefore, it is very important to investigate herbal products that both prevent/cure AD and reduce AD-related oxidative stress, as they may have fewer side effects. In this study, the protective effects of parsley (Petroselinum crispum) extract on lens tissues of an experimental AD model induced by scopolamine were examined and evaluated through biochemical parameters. The result of biochemical experiments and principal component analysis, was observed that parsley extract had a therapeutic effect by reducing oxidative stress in lens tissues of experimentally induced AD rats. It can be suggested that the phenolic and flavonoid-rich content of parsley extract may have caused the reduction of oxidative damage in lens tissues and can be used to protect lens tissue against oxidative stress due to AD disease.Article Citation - WoS: 4Citation - Scopus: 4Whey Protein Concentrate Ameliorates the Methotrexate-Induced Liver and Kidney Damage(Cambridge Univ Press, 2023) Tufan, Elif; Sivas, Guezin Goksun; Gurel-Gokmen, Begum; Yilmaz-Karaoglu, Suemeyye; Dursun, Ercan; Caliskan-Ak, Esin; Tunali-Akbay, Tugba; Yllmaz-Karaoǧlu, SÜmeyye; Çallşkan-Ak, EsinMethotrexate (MTX) is a cytotoxic immunosuppressant that is widely used in the treatment of tumours, rheumatoid arthritis and psoriasis. This study aims to evaluate the effects of whey proteins on MTX-induced liver and kidney damage by focusing on oxidant-antioxidant systems and eating habits. The study was conducted in four groups of thirty Sprague-Dawley rats (control, control + whey protein concentrate (WPC), MTX, MTX + WPC). A single dose of 20 mg/kg MTX was administered intraperitoneally to the MTX groups. Control and MTX groups were given 2 g/kg WPC by oral gavage every day for 10 d. At the end of day 10, blood samples were drawn and liver and kidney tissues were removed. MTX administration increased the lipid peroxidation level and decreased glutathione level, superoxide dismutase and glutathione-S-transferase activities in the liver and kidney. Administration of WPC significantly reduced the damage caused by MTX in the liver and kidney. While a decrease in serum urea level and an increase in serum creatinine level were detected in the MTX group, WPC administration reversed these results up to control group levels. Administration of WPC to the MTX group significantly reversed the histopathological damage scores of the liver and kidney. WPC administration ameliorated the MTX-induced oxidative damage in the liver and kidney tissues due to its antioxidant properties. Liver and kidney damage can be prevented by using whey proteins as a nutraceutical in MTX therapy. In conclusion, whey proteins demonstrated a protective effect against MTX-induced liver and kidney damage.Article The Protective Effects of Myrtus Communis Subsp. on Ovariectomized Diabetic Rats’ Renal and Intestinal Tissues: in Vivo and in Silico Approaches(Taylor and Francis Ltd., 2025) Ertik, O.; Kadıoğlu-Yaman, Beril; Şen, Ali; Şener, Göksel; Yanardag, RefiyeIntroduction: Postmenopausal diabetes is a condition that affects millions of women and their quality of life. Also, kidney and small intestine tissues are damaged due to diabetes. The present study aimed to examine the protective effects of an extract prepared from Myrtus communis leaves on kidney and small intestine tissues against experimentally created postmenopausal diabetes. Methods: For this purpose, experimental rats were randomly divided into six groups (Control; ovariectomy:OVX, diabetic:D, ovariectomy + diabetic:OVX + D, ovariectomy + diabetic + oestrogen:OVX + D+E2, ovariectomy + diabetic + MC: OVX + D+MC) and kidney and small intestine tissues were taken after the experimental procedure. Results: Evaluations of biochemical parameters (glutathione and glutathione-related enzymes, antioxidant enzymes, etc.) showed that MC had a protective effect on kidney and small intestine tissues in diabetes and ovariectomy groups. Conclusion: It can be suggested that MC extract has a protective effect on small intestine and kidney tissues in postmenopausal diabetes and may be a good herbal source for this purpose. © 2024 Informa UK Limited, trading as Taylor & Francis Group.Article Citation - WoS: 1Histological and Biochemical Effects of an Ethanolic Extract of <i>myrtus Communis</I> Leaf on the Pancreases of Rats Fed High Fat Diets(Taylor & Francis Ltd, 2024) Kabatas, Gul Sinemcan; Ertas, Busra; Sen, Ali; Sener, Goksel; Ercan, Feriha; Akakin, DilekWe investigated the effects of an ethanolic extract of Myrtus communis subsp. communis (MC) leaves on the pancreases of rats fed with a high fat diet (HFD). Wistar albino rats were fed either with standard lab chow (Control group) or with a 45% fat diet (HFD and HFD+MC groups) for 4 months, with the MC extract (100 mg/kg) being administered by orogastric gavage to rats in the HFD+MC group during the last month. Blood and pancreas samples were collected from all experimental groups at the end of the study. Insulin and leptin levels, and the lipid profile, were analyzed in the blood serum. Pancreatic injury was assessed histologically. Insulin, nuclear factor kappa beta (NF-kappa B), and alpha-smooth muscle actin (alpha-SMA) were assessed using immunohistochemistry. Apoptosis was assessed using terminal deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL) immunohistochemistry. In addition, oxidant/antioxidant activity was analyzed by biochemical methods. Increased body weight, serum insulin and leptin levels, blood glucose level and pancreatic tissue malondialdehyde (MDA), 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels, myeloperoxidase (MPO) activity and decreased tissue glutathione (GSH) level were observed in the HFD group compared to the Control group, in addition to dyslipidemia. An increased histopathological damage score, pancreatic islet area, insulin, TUNEL, NF-kappa B and alpha-SMA immunoreactivity were seen in animals from the HFD group compared to the Control group. However, such pathological changes were reduced in the HFD+MC group. Our data indicate further investigation of MC extract as a therapeutic adjuvant for HFD-induced pancreatic injury, acting via anti-inflammatory and antioxidant mechanisms, is worth carrying out.Article Citation - WoS: 1Ameliorative Effects of Myrtus Communis L. Extract Involving the Inhibition of Oxidative Stress on High Fat Diet-Induced Testis Damage in Rats(Taylor & Francis Ltd, 2024) Coskunlu, Busra; Koroglu, M. Kutay; Hersek, Irem; Ertas, Busra; Sen, Ali; Sener, Goksel; Ercan, FerihaThe possible protective effects of Myrtus communis L. (MC) extract on a high fat diet (HFD)-induced testicular injury in a rat model were investigated using histological and biochemical methods. Wistar albino rats were divided into three groups: a standard diet control group; a HFD group; and an HFD+MC group. The HFD and HFD+MC groups were fed with a HFD for 16 weeks. MC extract (100 mg/kg) was given orally five days a week to the rats in the HFD+MC group during the last four weeks of the experiment. Leptin, triglyceride, high-density lipoproteins, cholesterol, estrogen, testosterone, LH and FSH were analyzed in blood serum. Sperm parameters were evaluated from the epididymis. Testicular morphology, proliferative, apoptotic and NADPH oxidase-2 (NOX2)-positive cells were evaluated histologically. Testicular oxidative stress parameters were analyzed biochemically. In the HFD group, lipid and hormone profiles were changed, abnormal spermatozoa, degenerated seminiferous tubules with apoptotic and NOX2-positive cells were increased in number, and sperm motility and germinal proliferative cells decreased compared to the control group. Moreover, testicular malondialdehyde, 8-hydroxy-2-deoxyguanosine and myeloperoxidase levels increased, whereas glutathione and superoxide dismutase levels decreased in the HFD group compared to the control group. All these histological and biochemical features were ameliorated by MC treatment of HFD-fed rats. In conclusion, HFD caused alterations in sperm parameters and testicular morphology by increasing oxidative damage and apoptosis. MC extract may have potential protective effects by inhibiting oxidative damage.Article Citation - WoS: 6Citation - Scopus: 5The Effect of Melatonin on Glycoprotein Levels and Oxidative Liver Injury in Experimental Diabetes(Wiley, 2023) Ertik, Onur; Sener, Goksel; Yanardag, RefiyeIn this present study, the duration of melatonin (Mel) administered to diabetic rats was prolonged so as to examine its effects on the biochemical liver parameters of diabetic rats. In the experiment, Male Sprague Dawley rats were divided randomly into five groups; the control, diabetic + Mel, diabetic, diabetic + insulin, and diabetic + Mel + insulin. Diabetes mellitus was induced by administration of a single dose of streptozotocin (60 mg/kg) intraperitoneally and rats were given vehicle as a solvent for Mel every day for 12 weeks. In the diabetic + Mel group, diabetic rats were administered Mel (10 mg/kg/day) for 12 weeks to treat diabetes. The diabetic + insulin group were diabetic rats given insulin (6 U/kg) subcutaneously for 12 weeks. The diabetic + Mel + insulin rats received insulin and Mel at the same dose and time. At the end of the experiment, the animals were decapitated and liver tissues were taken. The protective effect of Mel on liver tissue of diabetic rats was investigated, total antioxidant status, total oxidant status, reactive oxygen species, oxidative stress index, adenosine deaminase, xanthine oxidase, paraoxonase 1, sodium/potassium ATPase, myeloperoxidase, gamma-glutamyl transferase, sorbitol dehydrogenase, tumor necrosis factor-alpha, homocysteine, nitric oxide, glucose-6-phosphate dehydrogenase, and glycoprotein levels were determined in liver tissues. Treatment with Mel and/or insulin has been found to have a protective effect on biochemical parameters. The results showed that administration of Mel to diabetic rats prevented the distortion of the studied biochemical parameters of liver tissues.