Natural Terpenes Prevent Mitochondrial Dysfunction, Oxidative Stress and Release of Apoptotic Proteins during Nimesulide-Hepatotoxicity in Rats

Nimesulide, an anti-inflammatory and analgesic drug, is reported to cause severe hepatotoxicity. In this study, molecular mechanisms involved in deranged oxidant-antioxidant homeostasis and mitochondrial dysfunction during nimesulide-induced hepatotoxicity and its attenuation by plant derived terpenes, camphene and geraniol has been explored in male Sprague-Dawley rats. Hepatotoxicity due to nimesulide (80 mg/kg BW) was evident from elevated SGPT, SGOT, bilirubin and histo-pathological changes. Antioxidants and key redox enzymes (iNOS, mtNOS, Cu/Zn-SOD, Mn-SOD, GPx and GR) were altered significantly as assessed by their mRNA expression, Immunoblot analysis and enzyme activities. Redox imbalance along with oxidative stress was evident from decreased NAD(P)H and GSH (56% and 74% respectively; P<0.001), increased superoxide and secondary ROS/RNS generation along with oxidative damage to cellular macromolecules. Nimesulide reduced mitochondrial activity, depolarized mitochondria and caused membrane permeability transition (MPT) followed by release of apoptotic proteins (AIF; apoptosis inducing factor, EndoG; endonuclease G, and Cyto c; cytochrome c). It also significantly activated caspase-9 and caspase-3 and increased oxidative DNA damage (level of 8-Oxoguanine glycosylase; P<0.05). A combination of camphene and geraniol (CG; 1∶1), when pre-administered in rats (10 mg/kg BW), accorded protection against nimesulide hepatotoxicity in vivo, as evident from normalized serum biomarkers and histopathology. mRNA expression and activity of key antioxidant and redox enzymes along with oxidative stress were also normalized due to CG pre-treatment. Downstream effects like decreased mitochondrial swelling, inhibition in release of apoptotic proteins, prevention of mitochondrial depolarization along with reduction in oxidized NAD(P)H and increased mitochondrial electron flow further supported protective action of selected terpenes against nimesulide toxicity. Therefore CG, a combination of natural terpenes prevented nimesulide induced cellular damage and ensuing hepatotoxicity

Influence of total low dose fractionated radiation on growth and metastasis of mice Lewis lung carcinoma

Effects of prolonged fractionated ionized radiation in low doses on the growth and metastasis intensity of mice Lewis lung carcinoma (LLC) are studied. On the background of tumor growth, stimulation induced by irradiation in the selected mode of dose fractionation inhibition of spontaneous dissemination of tumor cells into lungs is observed. On the 23-rd day after cell inoculation metastases incidence in irradiated animals was 25 % lower; the number and size of lung metastases decreased by 1.6 and 1.7 times. In the remote terms of tumor growth inhibition of functional activity of macrophages – central effectors of non-specific anti-tumor immunity was revealed

Dynamics of free-radical processes in the animals after protracted influence of exogenous nitric oxide and ionizing radiation

Aim of the investigation was to study the influence of nitric oxide (NO) and low doses of ionizing radiation (LDIR) on free radical processes that occur in various tissues of mammalian organism. Fractionated LDIR irradia-tion was shown to temporarily disrupt an oxidative metabolism. At same time protracted NO inhalation causes more significant harmful effects. This indicated that there are two pathways of oxidative metabolism disruption caused by generation of reactive oxygen or nitrogen species in tissues of mammalian organism

Modification of oxidation metabolism by biological active preparation RAPAMID in mice with different radiosensitivity

Influence of Rapamid, new biological active preparation of natural origin with antioxidant properties, on oxidation metabolism in mice with different radiosensitivity under single total irradiated, doze 1.0 Gy, was investigated. The one usage course of Rapamid before irradiation, according to oxide metabolism values, exert considerable radioprotective efficacy upon radiosensitive C3H mice, whereas on radioresistant mice (line CBA) such course result in increasing of free radicals processes. The authors pay attention to necessity of individual approach when drugs with antioxidant properties are used

Effect of mineral water of Beryezovsky deposit on hematopoietic system of the irradiated animals

Effectiveness of radiomodifying action of natural mineral water (MW) of Berezovsky deposit in comparison with MW “Naftusya” was studied. It is shown that MW Berezovsky deposits are characterized by mild radioprotective properties. With prolonged use, MW deregulates prooxidant-antioxidant ratio and inhibits the oxidative metabolism in the peripheral blood of the animals

New approach to the approximation of «dose – effect» dependence during the human somatic cells irradiation

New data on cytogenetic approximation of the experimental cytogenetic dependence "dose - effect" based on the spline regression model that improves biological dosimetry of human radiological exposure were received. This is achieved by reducing the error of the determination of absorbed dose as compared to the traditional use of linear and linear-quadratic models and makes it possible to predict the effect of dose curves on plateau

Effects of the Poly(ADP-Ribose) Polymerase Inhibitor Olaparib in Cerulein-Induced Pancreatitis.

Activation of the constitutive nuclear and mitochondrial enzyme poly (ADP-ribose) polymerase (PARP) has been implicated in the pathogenesis of cell dysfunction, inflammation, and organ failure in various forms of critical illness. The objective of our study was to evaluate the efficacy and safety of the clinically approved PARP inhibitor olaparib in an experimental model of pancreatitis in vivo and in a pancreatic cell line subjected to oxidative stress in vitro. The preclinical studies were complemented with analysis of clinical samples to detect PARP activation in pancreatitis. Mice were subjected to cerulein-induced pancreatitis; circulating mediators and circulating organ injury markers; pancreatic myeloperoxidase and malondialdehyde levels were measured and histology of the pancreas was assessed. In human pancreatic duct epithelial cells (HPDE) subjected to oxidative stress, PARP activation was measured by PAR Western blotting and cell viability and DNA integrity were quantified. In clinical samples, PARP activation was assessed by PAR (the enzymatic product of PARP) immunohistochemistry. In male mice subjected to pancreatitis, olaparib (3 mg/kg i.p.) improved pancreatic function: it reduced pancreatic myeloperoxidase and malondialdehyde levels, attenuated the plasma amylase levels, and improved the histological picture of the pancreas. It also attenuated the plasma levels of pro-inflammatory mediators (TNF-α, IL-1β, IL-2, IL-4, IL-6, IL-12, IP-10, KC) but not MCP-1, RANTES, or the anti-inflammatory cytokine IL-10. Finally, it prevented the slight, but significant increase in plasma blood urea nitrogen level, suggesting improved renal function. The protective effect of olaparib was also confirmed in female mice. In HPDE cells subjected to oxidative stress olaparib (1 μM) inhibited PARP activity, protected against the loss of cell viability, and prevented the loss of cellular NAD levels. Olaparib, at 1μM to 30 μM did not have any adverse effects on DNA integrity. In human pancreatic samples from patients who died of pancreatitis, increased accumulation of PAR was demonstrated. Olaparib improves organ function and tempers the hyperinflammatory response in pancreatitis. It also protects against pancreatic cell injury in vitro without adversely affecting DNA integrity. Repurposing and eventual clinical introduction of this clinically approved PARP inhibitor may be warranted for the experimental therapy of pancreatitis

Mitochondrial DNA Damage Initiates a Cell Cycle Arrest by a Chk2-associated Mechanism in Mammalian Cells

Previous work from our laboratory has focused on mitochondrial DNA (mtDNA) repair and cellular viability. However, other events occur prior to the initiation of apoptosis in cells. Because of the importance of mtDNA in ATP production and of ATP in fuel cell cycle progression, we asked whether mtDNA damage was an upstream signal leading to cell cycle arrest. Using quantitative alkaline Southern blot technology, we found that exposure to menadione produced detectable mtDNA damage in HeLa cells that correlated with an S phase cell cycle arrest. To determine whether mtDNA damage was causatively linked to the observed cell cycle arrest, experiments were performed utilizing a MTS-hOGG1-Tat fusion protein to target the hOGG1 repair enzyme to mitochondria and enhance mtDNA repair. The results revealed that the transduction of MTS-hOGG1-Tat into HeLa cells alleviated the cell cycle block following an oxidative insult. Furthermore, mechanistic studies showed that Chk2 phosphorylation was enhanced following menadione exposure. Treatment of the HeLa cells with the hOGG1 fusion protein prior to menadione exposure resulted in an increase in the rate of Chk2 dephosphorylation. These results strongly support a direct link between mtDNA damage and cell cycle arrest