Amelioration of radiation-induced oxidative stress and biochemical alteration by SOD model compounds in pre-treated γ-irradiated rats

Efficiency of Thyme and Oregano Essential Oils in Counteracting the Hazardous Effects of Malathion in Rats

The widespread use of MLT may pose numerous hazards to animal breeding, health, and resilience due to the presence of MLT residues in animal feedstuffs, pastures, hay, and cereals. Many medicinal plants provide what is called a generalized anti-toxic remedy. The current study examined hazardous biochemical and histological reactions to MLT and the efficiency of ThEO and OEO essential oils as anti-toxic therapies to return to a natural state after MLT exposure. A total of 75 male albino rats were randomly assigned to two groups: (i) C - MLT, comprising 25 rats, served as the control group; and (ii) C + MLT, with 50 rats that were exposed to 5 mg/kg/BW. After exposure to MLT for 21 days, a return to normal status was determined by subdividing the C + MLT group into two equal groups: ThEO and OEO were used as treatments, with 100 mg/kg body weight of thyme and oregano essential oils, respectively, being administered for 21 days. The results showed a significant decrease in body weight gain (BWG) and final weight (FW) compared to C - MLT, while the therapeutic effects of ThEO and OEO enhanced FW and BWG. Our results indicated that MLT exposure resulted in deficient serum liver function, but that OEO and ThEO therapy brought about a significant improvement in liver enzyme function. Although there was no significant difference in serum aspartate transaminase (AST) or alkaline phosphatase (ALK-Ph) and a significant drop in alanine transaminase (ALT) and acetyl choline-esterase (AChE) levels, the C + MLT group showed hepatic fibrosis in the third stage. Furthermore, histological sections of the OEO and ThEO groups showed reduced hepatocellular damage, inflammation, and hepatic fibrosis. However, there was a significant increase in serum creatinine between the C + MLT and C - MLT groups following exposure to MLT. Histological sections of renal tissue from rats treated with OEO and ThEO showed reduced tubular damage, reduced interstitial inflammation, and preserved renal tissue architecture. In conclusion, OEO and ThEO are potential compounds for use as anti-toxic therapies to return to a natural state after MLT exposure. These compounds could serve as an experimental therapeutic approach against natural toxins, providing a solution to the problems of raising livestock that are exposed to nutritional toxicity.

Chemical and biological basis for development of novel radioprotective drugs for cancer therapy

Ionizing radiation (IR) causes chemical changes in biological systems through direct interaction with the macromolecules or by causing radiolysis of water. This property of IR is harnessed in the clinic for radiotherapy in almost 50% of cancers patients. Despite the advent of stereotactic radiotherapy instruments and other advancements in shielding techniques, the inadvertent deposition of radiation dose in the surrounding normal tissue can cause late effects of radiation injury in normal tissues. Radioprotectors, which are chemical or biological agents, can reduce or mitigate these toxic side-effects of radiotherapy in cancer patients and also during radiation accidents. The desired characteristics of an ideal radioprotector include low chemical toxicity, high risk to benefit ratio and specific protection of normal cells against the harmful effects of radiation without compromising the cytotoxic effects of IR on cancer cells. Since reactive oxygen species (ROS) are the major contributors of IR mediated toxicity, plethora of studies have highlighted the potential role of antioxidants to protect against IR induced damage. However, owing to the lack of any clinically approved radioprotector against whole body radiation, researchers have shifted the focus toward finding alternate targets that could be exploited for the development of novel agents. The present review provides a comprehensive insight in to the different strategies, encompassing prime molecular targets, which have been employed to develop radiation protectors/countermeasures. It is anticipated that understanding such factors will lead to the development of novel strategies for increasing the outcome of radiotherapy by minimizing normal tissue toxicity.

Neuroprotective effect of Wogonin on Rat's brain exposed to gamma irradiation

Wogonin (5,7-dihydroxy-8-methoxy flavone), an active component isolated from the root of Scutellaria baicalensis Georgi. Neurotoxic effects of γ irradiation have been established in humans and animals. The current study was designed to evaluate whether wogonin could restrain γ irradiation-induced neurotoxicity in rats and to explore the underlying mechanisms. Rats were divided into five groups, 10 rats each. Group 1 was orally administered distilled water and served as control. Group 2 received an oral daily dose of wogonin (30 mg/kg). Rats in group 3 were exposed to a whole-body single dose of γ-irradiation. Animals in group 4 received an oral daily dose of wogonin (30 mg/kg) for 15 days then exposed to a whole-body single dose of γ-irradiation. In group 5, rats were exposed to a whole-body single dose of γ-irradiation then were orally administered a daily dose of wogonin (30 mg/kg) for 15 days. There were significant increases in malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and Interleukin 6 (IL-6) levels and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) mRNA and protein expression. Whereas significant decreases in reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) level as well as nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) mRNA and protein expression in the irradiated group when compared with the relevant control. The cerebral cortex of irradiated rats showed vacuolization and nuclear pyknosis in the neuronal cells and focal gliosis. Wogonin administration pre- or post-irradiation significantly ameliorated all these previous effects. Wogonin had antioxidant and anti-inflammatory effects and ameliorated the histopathological changes in the brain.

Whole brain radiation-induced cognitive impairment: pathophysiological mechanisms and therapeutic targets

Radiation therapy, the most commonly used for the treatment of brain tumors, has been shown to be of major significance in tu-mor control and survival rate of brain tumor patients. About 200,000 patients with brain tumor are treated with either partial large field or whole brain radiation every year in the United States. The use of radiation therapy for treatment of brain tumors, however, may lead to devastating functional deficits in brain several months to years after treatment. In particular, whole brain radiation therapy results in a significant reduction in learning and memory in brain tumor patients as long-term consequences of treatment. Although a number of in vitro and in vivo studies have demonstrated the pathogenesis of radiation-mediated brain injury, the cel-lular and molecular mechanisms by which radiation induces damage to normal tissue in brain remain largely unknown. Therefore, this review focuses on the pathophysiological mechanisms of whole brain radiation-induced cognitive impairment and the iden-tification of novel therapeutic targets. Specifically, we review the current knowledge about the effects of whole brain radiation on pro-oxidative and pro-inflammatory pathways, matrix metalloproteinases (MMPs)/tissue inhibitors of metalloproteinases (TIMPs) system and extracellular matrix (ECM), and physiological angiogenesis in brain. These studies may provide a foundation for defin-ing a new cellular and molecular basis related to the etiology of cognitive impairment that occurs among patients in response to whole brain radiation therapy. It may also lead to new opportunities for therapeutic interventions for brain tumor patients who are undergoing whole brain radiation therapy.

SOD mimetic improves the function, growth, and survival of small-size liver grafts after transplantation in rats

BACKGROUND

Small-for-size syndrome (SFSS) may occur when graft volume is less than 45% of the standard liver volume, and it manifests as retarded growth and failure of the grafts and more mortality. However, its pathogenesis is poorly understood, and few effective interventions have been attempted.

AIMS

The present study aimed to delineate the critical role of oxidant stress in SFSS and protective effects of a superoxide dismutase mimetic, Mn(III)tetrakis(4-benzoic acid)porphyrin chloride (MnTBAP), on graft function, growth, and survival in the recipient rats.

METHODS

Small size graft liver transplantation (SSGLT) was performed to determine the survival, graft injury, and growth. MnTBAP was administered in SSGLT recipients (SSGLT+MnTBAP).

RESULTS

Serum alanine aminotransferase levels were sustained higher in SSGLT recipients, which were correlated with an increased apoptotic cell count and hepatocellular necrosis in liver sections. Malondialdehyde content, gene expression of tumor necrosis factor α and interleukin 1β, and DNA binding activity of nuclear factor-κB in the grafts were increased significantly in SSGLT recipients compared with sham-operated controls. Both phosphorylated p38 mitogen-activated protein kinase and nuclear c-Jun were increased in SSGLT. All these changes were strikingly reversed by the administration of MnTBAP, with an increase in serum superoxide dismutase activity. Moreover, in situ bromodeoxyuridine incorporation demonstrated that graft regeneration was much more profound in the SSGLT+MnTBAP group than in the SSGLT group. Finally, the survival of recipients with MnTBAP treatments was significantly improved.

CONCLUSIONS

Enhanced oxidant stress with activation of the p38/c-Jun/nuclear factor-κB signaling pathway contributes to SFSS-associated graft failure, retarded graft growth, and poor survival. MnTBAP effectively reversed the pathologic changes in SFSS-associated graft failure.

Mentha piperita as a pivotal neuro-protective agent against gamma irradiation induced DNA fragmentation and apoptosis : Mentha extract as a neuroprotective against gamma irradiation

Ionizing radiation is classified as a potent carcinogen, and its injury to living cells, in particular to DNA, is due to oxidative stress enhancing apoptotic cell death. Our present study aimed to characterize and semi-quantify the radiation-induced apoptosis in CNS and the activity of Mentha extracts as neuron-protective agent. Our results through flow cytometry exhibited the significant disturbance and arrest in cell cycle in % of M1: SubG1 phase, M2: G0/1 phase of diploid cycle, M3: S phase and M4: G2/M phase of cell cycle in brain tissue (p < 0.05). Significant increase in % of apoptosis and P53 protein expression as apoptotic biomarkers were coincided with significant decrease in Bcl(2) as an anti-apoptotic marker. The biochemical analysis recorded a significant decrease in the levels of reduced glutathione, superoxide dismutase, deoxyribonucleic acid (DNA) and ribonucleic acid contents. Moreover, numerous histopathological alterations were detected in brain tissues of gamma irradiated mice such as signs of chromatolysis in pyramidal cells of cortex, nuclear vacuolation, numerous apoptotic cell, and neural degeneration. On the other hand, gamma irradiated mice pretreated with Mentha extract showed largely an improvement in all the above tested parameters through a homeostatic state for the content of brain apoptosis and stabilization of DNA cycle with a distinct improvement in cell cycle analysis and antioxidant defense system. Furthermore, the aforementioned effects of Mentha extracts through down-regulation of P53 expression and up-regulation of Bcl(2) domain protected brain structure from extensive damage. Therefore, Mentha extract seems to have a significant role to ameliorate the neuronal injury induced by gamma irradiation.

Mitigation of radiation-induced lung injury by genistein and EUK-207

PURPOSE

We examined the effects of genistein and/or Eukarion (EUK)-207 on radiation-induced lung damage and investigated whether treatment for 0-14 weeks (wks) post-irradiation (PI) would mitigate late lung injury.

MATERIALS AND METHODS

The lungs of female Sprague-Dawley (SD) rats were irradiated with 10 Gy. EUK-207 was delivered by infusion and genistein was delivered as a dietary supplement starting immediately after irradiation (post irradiation [PI]) and continuing until 14 wks PI. Rats were sacrificed at 0, 4, 8, 14 and 28 wks PI. Breathing rate was monitored and lung fibrosis assessed by lung hydroxyproline content at 28 wks. DNA damage was assessed by micronucleus (MN) assay and 8-hydroxy-2-deoxyguanosine (8-OHdG) levels. The expression of the cytokines Interleukin (IL)-1α, IL-1β, IL-6, Tumor necrosis factor (TNF)-α and Transforming growth factor (TGF)-β1, and macrophage activation were analyzed by immunohistochemistry.

RESULTS

Increases in breathing rate observed in the irradiated rats were significantly reduced by both drug treatments during the pneumonitis phase and the later fibrosis phase. The drug treatments decreased micronuclei (MN) formation from 4-14 wks but by 28 wks the MN levels had increased again. The 8-OHdG levels were lower in the drug treated animals at all time points. Hydroxyproline content and levels of activated macrophages were decreased at 28 wks in all drug treated rats. The treatments had limited effects on the expression of the cytokines.

CONCLUSION

Genistein and EUK-207 can provide partial mitigation of radiation-induced lung damage out to at least 28 wks PI even after cessation of treatment at 14 wks PI.

Antioxidant properties of probiotics and their protective effects in the pathogenesis of radiation-induced enteritis and colitis

Radiation therapy has become one of the most important treatment modalities for human malignancy, but certain immediate and delayed side-effects on the normal surrounding tissues limit the amount of effective radiation that can be administered. After exposure of the abdominal region to ionizing radiation, nearly all patients experience transient symptoms of irradiation of the bowel. Acute-phase symptoms may persist for a short time, yet long-term complications can represent significant clinical conditions with high morbidity. Data from both experimental studies and clinical trials suggest the potential benefit for probiotics in radiation-induced enteritis and colitis. On the other hand, it is well evidenced that both useful and harmful effects of therapeutic applications of ionizing radiation upon living systems are ascribed to free-radical production. Therefore, the hypothesis that probiotics reinforce antioxidant defense systems of normal mucosal cells exposed to ionizing radiation may explain to an extent their beneficial action. The aim of this review is threefold: First, to make a short brief into the natural history of radiation injury to the intestinal tract. Second, to describe the primary interaction of ionizing radiation at the cellular level and demonstrate the participation of free radicals in the mechanisms of injury and, third, to try a more profound investigation into the antioxidant abilities of probiotics and prebiotics based on the available experimental and clinical data.

Effects of combined vanadate and magnesium treatment on erythrocyte antioxidant defence system in rats

The effect of vanadate and magnesium treatment on erythrocyte defence system was studied in outbred 2-month-old, albino male Wistar rats (14 rats/each group) which daily received: Group I (Control)-deionized water to drink; Group II-water solution of sodium metavanadate (NaVO(3); SMV) at a concentration of 0.125mgV/mL; Group III-water solution of magnesium sulfate (MgSO(4); MS) at a concentration of 0.06mgMg/mL, Group IV-water solution of SMV-MS at the same concentrations over a 12-week time. The fluid intake and the concentration of reduced glutathione (GSH) as well as the activity of Cu, Zn-superoxide dismutase (Cu, Zn-SOD), catalase (CAT) and glutathione reductase (GR) were significantly decreased in the rats receiving SMV alone (Group II) or in combination with MS (Group IV) compared with Groups I and III. The cellular glutathione peroxidase (cGSH-Px) activity was unchanged in all the treated groups. The activity of glutathione S-transferase (GST) fell in the animals in Group II, compared with the rats in Groups I, III and IV; whereas in the rats in Group III its activity was higher than in the control animals. These results showed that V (as SMV) consumed by the rats with drinking water at a dose of 12mgV/kg b.w./24h for 12 weeks may attenuate defence system in rats' erythrocytes (RBCs), which is probably a consequence of vanadium pro-oxidant potential. Therefore, reactive oxygen species (ROS) are suggested to be involved in the alterations in antioxidant defence system in these cells. Mg (as MS) at the dose ingested (6mgMg/kg b.w./24h) at co-exposure to SMV was not able to counteract its deleterious effect. The results also provide evidence that V-Mg interactions may be involved in the decrease of erythrocyte GR activity and Mg concentration in the plasma under concomitant treatment with both metals at the doses of 12.6mgV and 6mgMg/kg b.w./24h.

Possible role of vitamin E, coenzyme Q10 and rutin in protection against cerebral ischemia/reperfusion injury in irradiated rats

PURPOSE

To investigate the possible role of vitamin E, coenzyme Q10 and rutin in ameliorating the biochemical changes in brain and serum induced by cerebral ischemia/reperfusion (I/R) in whole body γ-irradiated rats.

MATERIALS AND METHODS

Cerebral ischemia was induced in male Wistar rats (either irradiated or non-irradiated) followed by reperfusion.

RESULTS

I/R increased brain content of malondialdehyde (MDA) and depleted its glutathione (GSH) content with a compensatory elevation in cytosolic activities of glutathione peroxidase (GPx) and glutathione reductase (GR) enzymes. It also raised brain cytosolic lactate dehydrogenase (LDH) activity and calcium (Ca(2+)) level. Furthermore, I/R provoked an inflammatory response reflected by an increment in serum levels of the proinflammatory cytokines tumour necrosis factor-α (TNF-α) and interlukin-1β (IL-1β). Moreover, induction of I/R in irradiated rats resulted in a further increase in brain oxidative stress and cytosolic LDH activity, disturbed brain Ca(2+) homeostasis and exaggerated the inflammatory reaction. During irradiation, administration of each of vitamin E, coenzyme Q10 (CoQ10) and rutin to irradiated rats before induction of I/R, alleviated the brain oxidative stress. Moreover, these antioxidants caused attenuation of the rise of the cytosolic activities of GPx and GR. A lowering effect of the cytosolic LDH activity and Ca(2+) level were caused by treatment with antioxidants. Each of vitamin E and rutin revealed an anti-inflammatory action of these antioxidants, while CoQ10 had no effect on serum levels of TNF-α and IL-1β.

CONCLUSION

These findings indicate that supplementation with either vitamin E, CoQ10 or rutin ameliorated most of the biochemical changes induced by I/R in irradiated rat brain and serum.

Study of potential systemic oxidative stress animal models for the evaluation of antioxidant activity: status of lipid peroxidation and fat-soluble antioxidants

Although many compounds have already been tested in-vitro to determine their antioxidant profile, it is necessary to investigate the in-vivo effect of potential antioxidants. However, representative models of systemic oxidative stress have been poorly studied. Here, different potential systemic oxidative stress animal models have been investigated. These included a vitamin E-deficient rat, a diabetic rat and an atherosclerotic rabbit model. Plasma/serum malondialdehyde was measured as a parameter of oxidative damage. Plasma/serum fat-soluble antioxidants were determined as markers of antioxidant defence. We demonstrated that vitamin E-deficient rats were not suitable as a model of systemic oxidative stress, whereas diabetic and atherosclerotic animals showed increased systemic oxidative damage, as reflected by significantly augmented plasma/serum malondialdehyde. Moreover, plasma coenzyme Q9 increased by 80% in diabetic rats, confirming systemic oxidative stress. In view of these observations and economically favouring factors, the diabetic rat appeared to be the most appropriate systemic oxidative stress model. These findings have provided important information concerning systemic oxidative stress animal models for the in-vivo study of antioxidants.

The evaluation of the oxidant injury as a function of time following brain irradiation in a rat model

This study presents the evaluation of the oxidant injury as a function of time following brain irradiation in a rat model. Thirty-five Wistar rats were divided into seven groups. The rats in Group 1 through Group 6 underwent irradiation, whereas the rats in Group 7 underwent sham irradiation. The rats in Group 1 through Group 6 underwent euthanasia at 1 through 48 h following irradiation, whereas the rats in Group 7 underwent euthanasia immediately following sham irradiation. At the time of euthanasia, the brain tissue was dissected for evaluation of the malondialdehyde (MDA) level and the superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSHPX) activities. The mean MDA levels were increased and the mean SOD, CAT and GSHPX activities were decreased at all of the time points for evaluation for the rats that underwent irradiation as compared to the rats that underwent sham irradiation, substantial for Group 1 and gradually leveling out through Group 6. This study confirms that the oxidant injury is evaluated at its best through the first several hours following brain irradiation.

Orally active antioxidative copper(II) aspirinate: synthesis, structure characterization, superoxide scavenging activity, and in vitro and in vivo antioxidative evaluations

Ever since it was proposed that reactive oxygen species (ROS) are involved in the pathogeneses of various diseases, superoxide dismutase (SOD)-mimetic complexes have been intensively studied. We prepared copper(II) aspirinate [Cu2(asp)4] from Cu(II) and aspirin, which has been in use for many years as an antipyretic, an analgesic, and an anti-inflammatory agent. However, Cu2(asp)4 has been found to have additional activities, including anti-inflammatory, antiulcer, anti-ischemic/reperfusion agent, anticancer, antimutagenic, and antimicrobial activities. The activity of copper salicylate [Cu(sal)2] was also compared with that of Cu2(asp)4. The structure of the Cu2(asp)4 was determined using X-ray structure analysis. Its SOD-mimetic activity was determined using cytochrome c, electron spin resonance (ESR) spectroscopy, and ESR spin trap methods. The activity of Cu2(asp)4 was slightly greater than CuSO4 and copper acetate [Cu(ace)2] and slightly less than that of Cu(sal)2. The in vitro antioxidant activity, evaluated in human epithelial or transformed neoplastic keratinocyte cells, HaCaT, and normal dermal fibroblasts in terms of cell survival following ultraviolet B (UVB) irradiation, was significantly increased in the presence of Cu2(asp)4, Cu(sal)2, and CuSO4. Further, ROS generation following UVA irradiation in the skin of hairless mice following oral treatment with Cu2(asp)4 for three consecutive days was significantly suppressed compared to the vehicle- or Cu(ace)2-treated mice. On the basis of these results, Cu2(asp)4 was observed to be a potent antioxidative compound possessing antioxidative activity in biological systems. In conclusion, Cu2(asp)4 is a potent antioxidative agent that may be useful for future treatment of diseases resulting from ROS.

Orally active antioxidative copper(II) aspirinate: synthesis, structure characterization, superoxide scavenging activity, and in vitro and in vivo antioxidative evaluations

Ever since it was proposed that reactive oxygen species (ROS) are involved in the pathogeneses of various diseases, superoxide dismutase (SOD)-mimetic complexes have been intensively studied. We prepared copper(II) aspirinate [Cu2(asp)4] from Cu(II) and aspirin, which has been in use for many years as an antipyretic, an analgesic, and an anti-inflammatory agent. However, Cu2(asp)4 has been found to have additional activities, including anti-inflammatory, antiulcer, anti-ischemic/reperfusion agent, anticancer, antimutagenic, and antimicrobial activities. The activity of copper salicylate [Cu(sal)2] was also compared with that of Cu2(asp)4. The structure of the Cu2(asp)4 was determined using X-ray structure analysis. Its SOD-mimetic activity was determined using cytochrome c, electron spin resonance (ESR) spectroscopy, and ESR spin trap methods. The activity of Cu2(asp)4 was slightly greater than CuSO4 and copper acetate [Cu(ace)2] and slightly less than that of Cu(sal)2. The in vitro antioxidant activity, evaluated in human epithelial or transformed neoplastic keratinocyte cells, HaCaT, and normal dermal fibroblasts in terms of cell survival following ultraviolet B (UVB) irradiation, was significantly increased in the presence of Cu2(asp)4, Cu(sal)2, and CuSO4. Further, ROS generation following UVA irradiation in the skin of hairless mice following oral treatment with Cu2(asp)4 for three consecutive days was significantly suppressed compared to the vehicle- or Cu(ace)2-treated mice. On the basis of these results, Cu2(asp)4 was observed to be a potent antioxidative compound possessing antioxidative activity in biological systems. In conclusion, Cu2(asp)4 is a potent antioxidative agent that may be useful for future treatment of diseases resulting from ROS.