Epigenetics and Cartilage Regeneration

Regenerative cartilage therapy has great potential for the treatment of debilitating diseases such as osteoarthritis and rheumatoid arthritis. Recent advances in the field of epigenetics have enabled us to understand more clearly the role of micro RNAs, DNA methylations and histone modification in disease progression, as well as its potential role in disease prevention. However, a thorough understanding of the external dietary and environmental factors that could affect the epigenetic events could be the key to unravelling novel therapeutic strategies for these diseases. There is, therefore, a need for identifying certain dietary or environmental factors that could change this downward epigenetics signalling cascade, stop or retard cartilage degradation and promote cartilage regeneration

Neuroprotective Role of Glutathione against Hydrogen Peroxide Induced Toxicity to the Neuronal Cells in Culture

Neuropathophysiology research is receiving considerable attention. Studies have demonstrated that under oxidative stress, reactive oxygen species (ROS) generated at high levels inducing cellular and DNA damage, thereby resulting in apoptosis of neuronal cells. This is implicated in the etiology of several neurodegenerative and neurodevelopmental disorders. This study was undertaken to examine the role of glutathione as a Neuroprotective bioactive compound on hydrogen peroxide-induced apoptosis. Assessment of DNA damage with the help of Comet assay (single cell gel electrophoresis) and DNA fragmentation Assay were carried out on cultured SH-SY5Y neuroblastoma cells. The treatment with glutathione markedly attenuated hydrogen peroxide-induced cell viability loss and apoptotic neuronal cell death. These results provide evidence that glutathione may act as a significantly bioactive compound and support the possibility that it may be important in health and disease, and for protection against DNA damage by oxidative stress

Neuroprotective effect of quercetin in murine cortical brain tissue cultures

Summary: Purpose: Quercetin (QR) is bioflavonoids known for its antioxidants property and its ability to alleviate oxidative stress and promote cellular survival. The aim of this study was to explore the neuroprotective potential of QR against the induced oxidative stress. Methods: Cortical brain tissue cultures from one week old Wister rats were set up in four groups. Group 1: the control group without any treatments; Group 2: cortical cultures treated with 1 mM H2O2 for one hour; Group 3: Cortical cultures pretreated with varying doses of QR for 24 h followed by treatment with 1 mM H2O2 for 1 h; Group 4: Cortical cultures treated with the vehicle alone (DMSO). The cortical Tissues from all four groups were homogenized, both the homogenized cortical tissues and conditioned medium was used for the biochemical assay. For histology studies cortical brain tissue were fixed in 10% formalin and stained with H&E. Results: Pretreatment with 100 μg/ml showed the optimum concentration, which completely ameliorates the effect of induced oxidative stress by H2O2. All of the biochemical markers of oxidative stress such as lipid peroxidation, GST enzyme assay, DNA damage and fragmentation were completely reversed with the pretreatments of QR. Histology of the cortical tissues further confirmed the biochemical assays as it showed the pretreatments with QR resulted in the neuronal survival and viability. Conclusions: This study further reiterated the neuroprotective role of QR against oxidative stress-related neurodegenerative disorders. Keywords: Oxidative stress (OS), Quercetin (QR), Neuroprotection, Cortical brain cultures, Lipid peroxidation, DNA damag

Neuroprotective role of vitamin D in primary neuronal cortical culture

Background: A role of Vitamin D in brain development and function has been gaining support over the last decade. There are compelling pieces of evidence that suggest vitamin D may have a neuroprotective role. The administration of vitamin D or its metabolites has been shown to reduce neurological injury and/or neurotoxicity in a variety of animal systems. The detail biochemical mechanism mediating neurons, to its ability to withstand greater oxidative stress in the presence of Vitamin D is unclear. This study was undertaken to study the biochemical effect of treatments of primary cortical neuronal cultures, with the active form of vitamin D(1,25(OH)2D3), against the induced oxidative stress. Methods: Primary neuronal cultures from cerebral cortex were set up from neonatal (from 6 to 7 days old) Wister Rat's brain. Different doses of [1,25(OH)2D3], ranges from 0 to 1 μg/ml, was added to the culture medium and the cells were cultured in its presence for 24 h to 120 h. The effect of induced extracellular oxidative stress was measured by subjecting these cultured cells with 0.5 mM H2O2 for 2 h, prior to collection of condition medium and the cell pellet for biochemical assay. The control and H2O2 treated cultures were maintained in similar culture conditions, for similar periods of time without any [1,25(OH)2D3] treatments. Result: The optimum concentration of [1,25(OH)2D3] for treatment of primary cortical neuronal cultures was found to be 0.25 μg/ml by Trypan exclusion assay and MTT assay. Pre-treatments of cultured neuronal cells with 0.25 μg/ml of [1,25(OH)2D3] caused significantly increased levels of reduced glutathione, accompanied by a similar increase in the enzyme levels of GST, to neutralize the induced oxidative stress by H2O2. The level of Lipid peroxidation was significantly higher in the cells treated with H2O2 alone, but it was completely reversed in the neuronal cultures pre-treated with [1,25(OH)2D3]. The levels of Catalase enzyme also significantly reduced (≥0.05) in the [1,25(OH)2D3] pre-treated neuronal cultures. Conclusion: We concluded that the systemic treatment of primary neuronal cultures with [1,25(OH)2D3] gave better protection to neurons against the induced oxidative stress, as shown by quantitative measurements of various biomarkers of oxidative stress. This study also suggested that Vitamin D is vital for the growth, survival, and proliferation of the neurons and hence it has a potential therapeutic role against various neurodegenerative diseases

In-Vitro Inhibition of Camel Hepatic Glutathione Transferase by Quercetin

Abstract: Glutathione S-transferases (GST) are a group of multifunctional ubiquitous enzymes widely present in animals and plants, which catalysis the conjugation of glutathione to different exogenous and endogenous electrophilic compounds. This study was carried out to characterize the purified GST enzyme from camel liver tissues and to investigate the in-vitro inhibitory effect of the flavonoid quercetin by measuring S-2,4-dinitrophenyl glutathione (DNP-GSH) formation from 1-chloro-2,4-dinitrobenzene (CDNB) and reduced glutathione(GSH) as substrates. The Km values for reduced GSH and CDNB were found to be 0.08438 and 0.6827 mM while Vmax values were 6.935 and 15.599 mM/min respectively. The IC 50 was determined to be 1.8 mM. The inhibition constant (Ki) was estimated to be 1.91 mM at 0.5 mM and 1.76 mM at 2 mM. The mean inhibition constant (Ki) was estimated to be 1.835±0.075mM which revealed an uncompetitive profile and indicated quercetin as a weak inhibitor with the varied concentration of CDNB and fixed concentration of reduced GSH as a substrate

The systemic effect of PEG-nGO-induced oxidative stress in vivo in a rodent model

Oxidative stress (OS) plays an important role in the pathology of certain human diseases. Scientists have developed great interest regarding the determination of oxidative stress caused after the administration of nano-graphene composites (PEG-nGO). Graphene oxide sheets (GOS) were synthesized via a modified Hummer's method and were characterized by X-ray diffraction (XRD), ultraviolet–visible spectroscopy (UV), and transmission electron microscopy (TEM). The method of Zhang was adopted for cracking of GOS. Then nano-graphene oxide was PEGylated with polyethylene glycol (PEG). PEGylation of nGO was confirmed by Fourier-transform infrared spectroscopy (FTIR), UV spectroscopy and TEM. The average size distribution of nGO and PEG-nGO was determined by using dynamic light scattering (DLS). Subsequently, an in vivo study measuring a marker for oxidative stress, namely lipid peroxides, as well as antioxidant agents, including catalase, superoxide dismutase, glutathione, and glutathione S-transferase was conducted. A comparison at different intervals of time after the administration of a dose (5 mg/kg) of PEG-nGO was carried out. An increase in free radicals and a decrease in free radical scavenging enzymes in organs were observed. Our results indicated that the treatment with PEG-nGO caused an increased OS to the organs in the first few hours of treatment. However, the liver completely recovered from the OS after 4 h. Brain, heart and kidneys showed an increased OS even after 4 h. In conclusion increased OS induced by PEG-nGO could be detrimental to brain, heart and kidneys