Oxidative Stress and Autophagy

Free radical production related with many stress factors including radiation, drugs, ageing and trauma plays a key role in cell death. Notwithstanding, free radicals can cause pathology in a variety of diseases through oxidative stress: Under oxidative stress, excessive production of free radicals can trigger cell death by primarily DNA and all cellular macromolecule damages. Also, excessive free radicals have a role in early inducers of autophagy cell death upon nutrient deprivation. Autophagy is physiologic process of eukaryotic systems, which have significant role in adaptation to oxidative stress by degradation of metalloproteins and oxidatively damaged macromolecules. By oxidizing, membrane injuries allow the leakage of enzymes and contribute to cell damage. However, recent publications demonstrate the protecting role of lysosome system during excessive reactive oxygen species (ROS) production by the elimination of damaged proteins or organelles. Activation of autophagic or lysosomal system can eliminate the oxidizing components of cell in oxidative stress response. This chapter aims to provide the novel insight data for oxidative damage-mediated autophagy as well as their metabolic networks

Therapeutic Effects of Melatonin on Alveolar Bone Resorption After Experimental Periodontitis in Rats: A Biochemical and Immunohistochemical Study

DUMAN, SUAYIP BURAK/0000-0003-2552-0187; Kara, Adem/0000-0002-5766-6116WOS: 000357205800006PubMed: 25812911Background: the present study aims to investigate the effects of systemic melatonin administration on alveolar bone resorption in experimental periodontitis in rats. Methods: Twenty-four male Sprague-Dawley rats were divided into three groups (control, experimental periodontitis [Ped], and experimental periodontitis treated with melatonin [Mel-Ped]). For periodontitis induction, first molars were ligatured submarginally for 4 weeks. After ligature removal, rats in the Mel-Ped group were treated with a daily single dose of 10 mg/kg body weight melatonin for 15 consecutive days. At the end of the study, intracardiac blood samples and mandible tissues were obtained for histologic, biochemical, and radiographic analysis. Serum markers related to bone turnover, calcium, phosphorus, bone alkaline phosphatase (b-ALP), and terminal C telopeptide of collagen Type I (CTX) were analyzed. Myeloperoxidase levels were determined in gingival tissue homogenates, and receptor activator of nuclear factor-kappa B ligand (RANKL) activation was analyzed in the mandible samples stereologically. Alveolar bone loss was also evaluated radiographically in the mandible samples of each group. Results: Melatonin treatment decreased serum CTX levels and increased b-ALP levels. Serum calcium and phosphorus levels were not statistically different among groups (P >0.05). Alveolar bone resorption and myeloperoxidase activity were statistically higher in the Ped group compared to the Mel-Ped group (P <0.05). Immunohistochemical staining of RANKL and osteoclast activity were significantly lower in the Mel-Ped group compared to the Ped group (P <0.05). Conclusion: This study reveals that melatonin treatment significantly inhibits regional alveolar bone resorption and contributes to periodontal healing in an experimental periodontitis rat model

Influences of Fucoxanthin on Alveolar Bone Resorption in Induced Periodontitis in Rat Molars

Kara, Adem/0000-0002-5766-6116; Kose, Oguz/0000-0002-0318-2458; ARABACI, TANER/0000-0003-0476-1010WOS: 000374588000009PubMed: 27043583The aim of this study was to evaluate the effects of systemic fucoxanthin treatment on alveolar bone resorption in rats with periodontitis. Thirty rats were divided into control, experimental periodontitis (EP), and experimental periodontitis-fucoxanthin (EP-FUCO) groups. Periodontitis was induced by ligature for four weeks. After removal of the ligature, the rats in the EP-FUCO group were treated with a single dose of fucoxanthin (200 mg/kg bw) per day for 28 consecutive days. At the end of the study, all of the rats were euthanized and intracardiac blood and mandible tissue samples were obtained for biochemical, immunohistochemical, and histometric analyses. Fucoxanthin treatment resulted in a slight decrease in tumor necrosis factor-alpha, interleukin-1 beta, and interleukin-6 levels and a significant decrease in oxidative stress index. It was observed that fucoxanthin caused a significant reduction in receptor activator of nuclear factor kappa-beta ligand (RANKL) levels and a statistically non-significant elevation in osteoprotegerin and bone-alkaline phosphatase levels. There were no significant differences in alveolar bone loss levels between the EP and EP-FUCO groups. This experimental study revealed that fucoxanthin provides a limited reduction in alveolar bone resorption in rats with periodontitis. One of the mechanisms underlying the mentioned limited effect might be related to the ability of fucoxanthin to inhibit oxidative stress-related RANKL-mediated osteoclastogenesis.Recep Tayyip Erdogan UniversityRecep Tayyip Erdogan University [Bap-2014.111.07.01]This study was supported by the Scientific Research Fund of Recep Tayyip Erdogan University (Bap-2014.111.07.01)