Pelargonidin ameliorates reserpine-induced neuronal mitochondrial dysfunction and apoptotic cascade: a comparative in vivo study

BACKGROUND

Targeting the neuronal mitochondria as a possible intervention to guard against neurodegenerative disorder progression has been investigated in the current work via the administration of pelargonidin (PEL) to rats intoxicated by the mitochondrial toxin reserpine. The main criteria for choosing PEL were its reported antioxidant, anti-apoptotic and anti-inflammatory activities.

METHODS

Male albino Wistar rats were randomized into five experimental groups; normal control, reserpinized to induce mitochondrial failure, standard PARP-1-inhibitor 1,5-isoquinolinediol (DIQ)-treated reserpinized, PEL-treated reserpinized, and GSK-3β inhibitor (AR-A 014418) -treated reserpinized.

RESULTS

PEL administration reversed the reserpine-induced abnormal behaviors marked by decreased catalepsy time. In addition, PEL restored brain glutathione with a reduction in nitric oxide content as compared to the reserpine-challenged group. Meanwhile, it improved neuronal mitochondrial function by the elevation of complex I activity associated with a low ADP/ATP ratio. Likely through its anti-inflammatory effect, PEL reduced the elevation of serum interleukin-1ß level and inhibited serum lactate dehydrogenase activity. These findings are aligned with the reduced expression of cleaved PARP and cleaved caspase-3 proteins, indicating PEL's suppressive effect on the intrinsic apoptotic pathway. Those biochemical findings were confirmed through comparable histopathological tissue examination among the experimental groups.

CONCLUSIONS

In conclusion, PEL is a promising candidate for future use in the management of mitochondria-associated neuronal complications via controlling the ongoing inflammatory and degeneration cascades.

Apigenin and Exposure to Low Dose Gamma Radiation Ameliorate Acetic Acid-Induced Ulcerative Colitis in Rats

Ulcerative colitis (UC) is an inflammatory bowel disease involving chronic and recurring colon inflammation. Current management protocols are limited by adverse effects or short-term symptomatic relief. We aimed to investigate the possible therapeutic prospect of low dose gamma (γ) irradiation or apigenin treatment in acetic acid-induced UC in rats. Induction of UC was carried out by installation of acetic acid intra-rectally. One hour post-induction, rats received a sole dose of γ-radiation (0.5 Gray) or were treated with apigenin (3 mg/kg/day, peroral) for 7 successive days. Antioxidant and anti-inflammatory effects of both agents were assessed via determination of colon malondialdehyde (MDA), reduced glutathione (GSH), total nitrate/nitrite (NOx), mucosal addressin cell adhesion molecule-1 (MAdCAM-1), and interleukin-1beta (IL-1β) contents as well as myeloperoxidase (MPO) activity. Body weight (BW), colon weight/length (W/L) ratio, disease activity index (DAI), and histopathological changes were evaluated. Gamma irradiation and apigenin significantly ameliorated the acetic acid-induced biochemical and histopathological changes. Both therapeutic approaches significantly restored colon contents of the investigated biomarkers. They modulated BW, colon W/L ratio and DAI. This study proposes low dose γ-irradiation as a new therapeutic candidate for the management of UC. We also concluded that apigenin exhibited therapeutic benefits in UC management.

Regulation of radiation-induced liver damage by modulation of SIRT-1 activity: In vivo rat model

Silent information regulator 1 (SIRT-1), a nicotinamide adenine dinucleotide-dependent deacetylase, was found to regulate cell apoptosis, inflammation, and oxidative stress response in living organisms. Therefore, the role of SIRT-1 in regulating forkhead box O/poly ADP-ribose polymerase-1 (FOXO-1/PARP-1) signaling could provide the necessary validation for developing new pharmacological targets for the promotion or inhibition of SIRT-1 activity toward radiation sensitivity. In the present study, the SIRT-1 signaling pathway is being investigated to study the possible modulatory effect of resveratrol (RSV, SIRT-1 activator) versus nicotinamide (NAM, SIRT-1 inhibitor) in case of liver damage induced by whole-body gamma irradiation. Rats were exposed to 6 Gy gamma radiation after being pretreated with either RSV (10 mg/kg/day) or NAM (100 mg/kg/day) for 5 days, and subsequent examining hepatic morphological changes and apoptotic markers were assessed. The expression of SIRT-1, FOXO-1, and cleaved PARP-1 in the liver was analyzed. RSV improved radiation-induced apoptosis, mitochondrial dysfunction, and inflammation signified by low expression of caspase-3, lactate dehydrogenase, complex-I activity, myeloperoxidase, and total nitric oxide content. RSV increased the expression of SIRT-1, whereas cleaved PARP-1 and FOXO-1 were suppressed. These protective effects were suppressed by inhibition of SIRT-1 activity using NAM. These findings suggest that RSV can attenuate radiation-induced hepatic injury by reducing apoptosis and inflammation via SIRT-1 activity modulation.

Molecular mechanisms involved in the effects of morin in experimental hepatic encephalopathy

This study aimed to investigate the possible usefulness of morin flavonoid in comparison to silymarin as a hepatic/neuronal-supportive agent with similar effects and higher bioavailability in a rat model of hepatic encephalopathy (HE). Morin effects on rat liver and brain were evaluated post-induction of HE by thioacetamide (TAA; 200 mg/kg/day for 3 successive days). Then, the serum activities of aspartate transaminase (AST) and alanine transaminase (ALT) together with ammonia concentration were estimated to assess the liver function. Also, the degree of brain effects was evaluated via the assessment of brain contents of reduced glutathione (GSH), malondialdehyde (MDA), tumor necrosis factor-alpha (TNF-α), and interleukin (IL-1β) together with glutathione peroxidase (GPx) activity. In addition, the apoptotic and inflammatory changes in brain and liver tissues were also assessed via immunohistochemical examination. Our findings revealed a promising effect of morin against HE complications; as it corrected the liver functions, attenuated the brain/liver tissue injuries, and reduced the apoptotic and inflammatory insults of HE on both organs. These effects are comparable to those of silymarin. Morin could be introduced as a promising hepato- and neuro-therapeutic adjuvant in HE-associated neuronal complications especially in cases like silymarin intolerance.

Tailoring of chitosan/diacrylated pluronic system as a versatile nanoplatform for the amelioration of radiation-induced cognitive dysfunction

Rutin (RUT) is a biologically active flavonoid that is reported to modulate radiation-induced brain dysfunctions. However, RUT's poor water solubility and low brain bioavailability limit its clinical use. To increase its brain bioavailability, RUT was loaded onto nanoplatforms based on chitosan/diacrylated pluronic (CS/DA-PLUR) nanogels synthesized by gamma radiation. The optimized formulation was investigated as a carrier system for RUT. Based on pilot experiments' results, the cranial radiation (CR) dose that induced cognitive dysfunction was selected. In the main experiment, rats were pre-treated orally with either free RUT or RUT-CS/DA-PLUR. Rats' cognitive and motor functions were assessed; 24 h later, rats were sacrificed, and the whole brain was separated for histopathological examination and biochemical estimation of brain content of acetylcholine esterase (AChE), neurotransmitters, oxidative stress markers, and interleukin-1β. CR produced prominent impairment in spatial and non-spatial learning memory, motor coordination, and muscular strength. Moreover, histopathological and biochemical alterations in brain contents of neurotransmitters, oxidative stress, and interleukin-1β were induced by CR. Conversely, RUT-CS/DA-PLUR, but not free RUT, successfully guarded against all the detrimental effects induced by CR. Based on the current findings, loading of RUT enhanced its bioavailability and therapeutic effectiveness by restoring the cognitive functions impaired by CR.

Ameliorative effect of fractionated low-dose gamma radiation in combination with ellagic acid on nicotine-induced hormonal changes and testicular toxicity in rats

Nicotine is an active pharmacological ingredient in cigarette smoke, which may negatively influence the male reproductive system and fertility. This study aims to investigate the effect of fractionated low-dose radiation (fractionated-LDR) and/or ellagic acid (EA) on nicotine-induced hormonal changes and testicular toxicity in rats. Nicotine was administrated orally (1 mg/kg) for 30 days, afterward, rats were treated with LDR (2 × 0.25 Gy/1-week interval), EA (10 mg/kg, 14 consecutive days p.o.), or a combination of both fractionated-LDR and EA. Rats were sacrificed 24 h after the last dose of treatment, then testes were dissected for histopathology examination, along with some biochemical parameters in serum and testicular tissue were evaluated. Nicotine-induced oxidative stress was evidenced by an increase in testicular thiobarbituric acid reactive substances (TBARS) and a decrease in reduced glutathione (GSH) content. Additionally, the activities of testicular androgenic enzymes were decreased, and the activity of serum lactate dehydrogenase (LDH) was significantly increased. The hormonal changes were verified by a noticeable reduction in follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone serum levels. Histological evaluation revealed that the testicular seminiferous tubules structure was distorted. On the contrary, fractionated-LDR plus EA attenuated the negative changes caused by nicotine observed through biochemical and histological findings. Accordingly, the exposure to fractionated-LDR combined with EA may be a promising candidate for treating hormonal changes and testicular toxicity caused by nicotine.

Effectiveness of deferiprone-loaded nanocarrier in experimentally induced rhabdomyolysis: A dose-comparison study

Herein, the efficacy of free deferiprone (DFP) and DFP-loaded starch/polyethylene glycol/polyacrylic acid (St/PEG/PAAc) nanogel [Nano-DFP] in modulating the biochemical changes induced by glycerol model of rhabdomyolysis (RBD) in male rats was investigated. In this respect, gamma radiation-induced crosslinking was used to produce St/PEG/PAAc nanogel particles, and then, it was used as a nanocarrier for DFP as an attempt to overcome the poor bioavailability and short half-life of DFP. St/PEG/PAAc nanogel was characterized by Fourier transform infrared, dynamic light scattering and Transmission electron microscopy. Free DFP was administered to rats in two doses; 25 and 50 mg following RBD induction, while the loaded nanogel was administered at a dose of 25 mg. The liver and kidney functions were then fully assessed in association with the histological tissue examination of both organs and the femur muscle. Both doses of DFP significantly antagonized the RBD-induced changes in most of the assessed organs functions. The higher dose of DFP, however, showed a statistically more pronounced modulation of RBD effects on each of kidney, liver and skeletal muscles. Nano-DFP; at 25 mg dose, resulted in a statistically significant correction of most of the RBD-related biomarkers with a comparable magnitude to the higher DFP dose rather than the corresponding lower one.

Amelioration of adjuvant-induced arthritis by exposure to low dose gamma radiation and resveratrol administration in rats

Purpose: Low dose radiation has been reported as an effective treatment for rheumatoid arthritis via multiple dose exposures. The present study was designed to increase the therapeutic efficacy of low dose radiation with the minimum exposure level in arthritic rats by concurrent administration of resveratrol (RSV) as an adjunctive therapy with anti-inflammatory properties.Materials and methods: Rats were rendered arthritic by sub-plantar injection of Freund's complete adjuvant (FCA) and exposed to low dose radiation at a total exposure level of 0.5 Gy (2 × 0.25). During the exposure course, RSV (50 mg/kg) was orally administered once daily for two weeks. Diclofenac (3 mg/kg) was administered as a standard anti-inflammatory drug. Paw volume was measured every 4 days. After 28 days of induction, rats were sacrificed and serum was collected for estimation of tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β), thiobarbituric acid reactive substances (TBARS), and total nitrate/nitrite (NO_x). Furthermore, paws were dissected for histopathological examinations and immuno-histochemical estimation of nuclear factor-kappa B p65 (NF-κB p65) expression.Results: Administration of RSV during the low dose radiation exposure course produced a significant decrease in the paw swelling and a potentiated inhibition in the serum levels of TNF-α, IL-1β, TBARs, and NO_x. The dual treatment strategy alleviated the histopathological damage to a greater extent than that produced by each treatment. Moreover, a pronounced suppression of NF-κB p65 expression in the synovial tissue was observed in the combination group. The combination treatment showed a nearly similar potency to that observed in the diclofenac treated group.Conclusion: Administration of RSV augmented the modulatory activity of low dose radiation with minimum exposure level on the disease progression.

Design and synthesis of novel pyridazinoquinazoline derivatives as potent VEGFR-2 inhibitors: In vitro and in vivo study

Worldwide, Hepatocellular Carcinoma (HCC) endures to be a prominent cause of cancer death. Treatment of HCC follows multiple therapies which are not entirely applicable for treatment of all patients. HCC usually arises contextual to chronic liver diseases and is often discovered at later stages which makes treatment options more complex. The present study aimed at design, synthesis & evaluation of new pyridazinoquinazoline derivatives as potential nontoxic anti-hepatocellular carcinoma (HCC) agents, through inhibition of Vascular endothelial growth factor -2 (VEGFR-2). Novel Pyridazino[3, 4, 5-de]quinazoline derivatives (2-6) were designed & synthesized. Their structures were confirmed via spectral and microanalytical data. They were tested for their in vitro VEGFR-2 inhibition & anticancer activity against human liver cancer cell line (HEPG-2). Molecular docking was investigated into VEGFR-2 site. In vivo studies of VEGRF-2 inhibition and the anti-apoptotic effect of the new compounds were determined in liver of irradiated rats. Toxicity of synthesized compounds was also assessed. The results showed that compounds 3-6 have significant antitumor activity and proved to be non-toxic. The ethoxy aniline derivative 6, exhibited the highest activity both in vitro and in vivo compared to the reference drug used, sorafenib. Compound 6 could be considered a promising nontoxic anti HCC agent and this could be partially attributed to its VEGFR-2 inhibition. Future preclinical investigation would be carried out to confirm the specific and exact mechanism of action of these derivatives especially compound 6 as an effective pharmaceutical agent after full toxicological and pharmacological assessment.

Propolis extract protects against radiation-induced intestinal mucositis through anti-apoptotic mechanisms

Intestinal mucositis is a common side effect during radiotherapy that could be largely prevented by compounds possessing anti-inflammatory or anti-oxidant properties, including extracts of propolis containing a high proportion of flavonoids. A specially formulated aqueous extract of propolis (PWE) has been prepared in such a way to preclude the inclusion of flavonoids but contain mostly organic aromatic acids to study whether it would still protect against radiation-induced intestinal mucositis and to study the possible involvement of apoptotic pathways. Rats were exposed to a gamma radiation dose of 8 Gy from a Cesium-137 source in order to inflict intestinal mucositis. Three days before exposure, rats were given PWE orally and treatment continued for 2 more days. Twenty-four hours later, rats were sacrificed, the small intestine was excised, and sections were examined histologically. Different parameters for apoptosis, inflammation, and oxidative stress were determined in the serum and in intestinal homogenates. Radiation exposure led to histological and biochemical signs of intestinal damage. This was associated with an increase in apoptotic indicators and derangement in oxidative stress parameters. All deranged parameters were largely prevented by PWE. The findings provide evidence that the protective effect of PWE against intestinal radiation damage involves not only its anti-inflammatory and anti-oxidant effects but also its anti-apoptotic properties as well.

Promising role of filgrastim and α-tocopherol succinate in amelioration of gastrointestinal acute radiation syndrome (GI-ARS) in mice

The protective role of α-tocopherol succinate (α-TCS) and the therapeutic efficacy of filgrastim were investigated in gastrointestinal acute radiation syndrome (GI-ARS) induced following 10 Gy whole-body γ-irradiation. Mice were randomly allocated into 5 groups: [1] normal-control, [2] irradiated-control, [3] subcutaneous (s.c.) injection of filgrastim (5 μg/kg/day) for 4 consecutive days given 1 h post-irradiation, [4] s.c. injection with α-TCS (400 mg/kg) 1 day prior to irradiation, [5] s.c. injection with α-TCS (400 mg/kg) 1 day prior to irradiation and filgrastim (5 μg/kg/day) for 4 consecutive days 1 h post-irradiation. Histopathological analysis, serum citrulline level, intestinal interleukin-1β (IL-1β), reduced glutathione (GSH), and malondialdehyde (MDA) contents as well as myeloperoxidase (MPO) activity were measured. Intestinal caspase-3, p53, cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS) immunopositivity were examined. In irradiated-control, MDA increased (249%) and GSH decreased (25%) compared to normal and were unaffected by filgrastim. α-TCS alone significantly reduced MDA (84.5%) and normalized GSH. The combination significantly reduced MDA (59%) and dramatically increased GSH (1573%), pointing to a possible synergistic action. In irradiated-control, MPO and IL-1β significantly increased (111% and 613%, respectively) compared to normal-control and both were significantly decreased in all treated groups. Compared to normal-control, citrulline significantly declined (68%) in irradiated-control; a significant elevation was achieved by treatments with α-TCS alone or combined with filgrastim (88% and 94%, respectively). The combination therapy significantly decreased the degree of irradiation-induced injury of the epithelium and cellular infiltration and showed the lowest histopathological scoring compared to the other groups (p ≤ 0.05). In irradiated-control, immune-reactive expressions of iNOS, COX-2, caspase-3, and p53 were remarkable (18.62%, 34.27%, 31.19%, and 27.44%, respectively) and after combination therapy were reduced (1.04%, 22.39%, 8.76%, and 4.91%, respectively). The current findings represent a first-hand strategy in dealing with GI-ARS with a potential preference to using a combined therapy of filgrastim and α-TCS.

Platelet-rich plasma-induced feedback inhibition of activin A/follistatin signaling: A mechanism for tumor-low risk skin rejuvenation in irradiated rats

BACKGROUND

Platelet-rich plasma (PRP) is a source of natural growth factors and is emerging as a treatment modality to mitigate radiotherapy- induced adverse effects. Activin A (ACTA) is a member of the transforming growth factor-β (TGF-β) superfamily, which has been shown to modulate the inflammatory response and macrophages polarization between different phenotypes. The aim of this study is to determine the value of PRP in preventing radiation-induced malignancies in light of the cross-talk between PRP and activin A type II receptors (ActR-IIA)/follistatin (FST) signaling pathways where the inflammatory responses at 2 different time points were evaluated.

MATERIAL AND METHODS

Male albino rats were exposed to radiation and given PRP over the course of 6 days. Rats were sacrificed on day 7 or day 28 post radiation.

RESULTS

Quantitative real-time reverse transcriptase polymerase chain reaction (QRT-PCR) and western-blot showed that after 7 days of administrating of PRP, ActR-IIA/FST signaling was markedly induced and was associated with the expressions of inflammatory, natural killer and M1 macrophages markers, TNF-α, IL-1β, IFN-γ and IL-12. By contrast, on day 28 of PRP administration, ActR-IIA/FST signaling and the expressions of proinflammatory cytokines were downregulated in parallel with inducing M2 macrophages phenotype as indicated by arginase-1, IL-10 and dectin-1.

CONCLUSION

The suppression of inflammation and induction of M2 macrophages phenotype in response to PRP administration were found significantly linked to ActR-IIA/FST signaling downregulation. Furthermore, the specific M2 macrophage subtype was found to express dectin-1 receptors which have high affinity for tumor cells thereby is expected to reduce the potential for developing tumors after radiotherapy.

Anti-apoptotic and antioxidant effects of low dose gamma irradiation against diabetes-induced brain injury in rats

The current study aimed to investigate the effect of different low doses of gamma irradiation on hyperglycemia-induced brain injury. The aim was further extended to investigate the sub-chronic effect of low dose radiation on the neuronal damage induced by diabetes. To induce diabetes, male albino rats were injected with dexamethasone (10 mg/kg/day, for 9 successive days, subcutaneously). Different diabetic groups were irradiated with 0.1, 0.25 and 0.5 Gy. The effect of low dose gamma irradiation on the hyperglycemia-induced brain damage based was analyzed at two levels: oxidative stress and apoptosis. The brain contents of glutathione, malondialdhyde and total nitrate/nitrite were measured to assess the oxidative stress. In order to evaluate the extent of the apoptotic changes in brain, tissue caspase-3 expression was detected using immunohistochemistry and the degree of DNA fragmentation was estimated. Moreover, brain tissues were examined using light microscopy to evaluate the histological changes in different groups and serum lactate dehydrogenase activity was determined as an indicator for the brain tissue damage. Results indicated that exposure to 0.5 Gy ameliorated the hyperglycemia and subsequently inhibited oxidative stress and apoptosis. Radiation exposure at this dose level also increased the survival rate of diabetic animals.

Propolis aqueous extract preserves functional integrity of murine intestinal mucosa after exposure to ionizing radiation

The ability of a specially prepared water propolis extract (PWE) to preserve the functional activity of the intestinal mucosa after radiation exposure was studied. PWE was given orally (650 mg/kg) to rats five days prior to irradiation by 6 Gy and continued for further two days. Rats were sacrificed 24h later, intestinal segments were examined histologically and homogenates were used to assess relevant biochemical parameters reflecting intestinal injury. Irradiation led to a rise in the histological damage score, a rise in tissue TNF-α and TBARS, and a decrease in sucrase, alkaline phosphatase, GSH and cholecystokinin as well as a decrease in plasma citrulline. The findings reflect a decrease in intestinal functional activity. PWE preserved the intestinal integrity and largely protected against the changes induced in the histology damage score and all parameters measured, possibly as a result of the antioxidant and anti-inflammatory action of its caffeic acid content.

3-aminobenzamide, a poly (ADP ribose) polymerase inhibitor, enhances wound healing in whole body gamma irradiated model

The custom use of radiotherapy was found to participate in the development of chronic unhealed wounds. In general, exposure to gamma radiation stimulates the production of reactive oxygen species (ROS) that eventually leads to damaging effect. Conversely, overexpression of a nuclear poly (ADP-ribose) polymerase enzyme (PARP) after oxidative insult extremely brings about cellular injury due to excessive consumption of NAD and ATP. Here, we dedicated our study to investigate the role of 3-aminobenzamide (3-AB), a PARP inhibitor, on pregamma irradiated wounds. Two full-thickness (6 mm diameter) wounds were created on the dorsum of Swiss albino mouse. The progression of wound contraction was monitored by capturing daily photo images. Exposure to gamma radiation (6Gy) exacerbated the normal healing of excisional wounds. Remarkably, topical application of 3-AB cream (50 µM) revealed a marked acceleration in the rate of wound contraction. Likewise, PARP inhibition ameliorated the unbalanced oxidative/nitrosative status of granulated skin tissues. Such effect was significantly revealed by the correction of the reduced antioxidant capacity and the enhanced lipid peroxidation, hydrogen peroxide, and myeloperoxidase contents. Moreover, application of 3-AB modified the cutaneous nitrite content throughout healing process. Conversely, the expressions of pro-inflammatory cytokines were down-regulated by PARP inhibition. The mitochondrial ATP content showed a lower consumption rate on 3-AB-treated wound bed as well. In parallel, the mRNA expressions of Sirt-1 and acyl-COA oxidase-2 (ACOX-2) were up-regulated; whom functions control the mitochondrial ATP synthesis and lipid metabolism. The current data suggested that inhibition of PARP-1 enzyme may accelerate the delayed wound healing in whole body gamma irradiated mice by early modifying the oxidative stress as well as the inflammatory response.

A multi-component herbal preparation, STW 5, shows anti-apoptotic effects in radiation induced intestinal mucositis in rats

PURPOSE

Intestinal mucositis is a common adverse effect in patients undergoing radiotherapy and constitutes a treatment-limiting condition. Since no agents are yet known that can adequately guard against its development, the search continues to find safe and effective measures. The present study was intended to investigate whether the herbal preparation, STW 5, could offer a potentially effective agent in this respect.

METHODS

Intestinal mucositis was induced in rats by exposing them to whole body gamma-irradiation (6 Gy). Rats were treated orally with STW 5 (5 or 10 ml/kg) for five days before and two days after irradiation. One day later, rats were sacrificed and segments of small intestine were examined histologically. Intestinal homogenates and serum samples were used to assess relevant parameters for apoptosis and different markers for inflammation and oxidative stress.

RESULTS

Exposure to radiation produced dose-dependent extents of intestinal injury associated with apoptotic changes with high radiation levels. Apoptosis was associated with an increase in cytosolic calcium, depletion of mitochondrial cytochrome c, B-cell lymphoma-2 and complex I. Oxidative stress parameters (reduced glutathione, thiobarbituric acid reactive substance and total nitrate/nitrite) were deranged. Inflammation markers (tumor necrosis factor and myeloperoxidase) and indices of intestinal damage (serum diamine oxidase) were increased. STW 5 protected to a large extent against histological changes and counteracted the deranged parameters.

CONCLUSION

The findings provide experimental evidence for the potential beneficial use of STW5 in protecting against the development of radiation-induced intestinal mucositis and associated changes in tissue biomarkers.

Activation of poly(ADP-ribose) polymerase-1 delays wound healing by regulating keratinocyte migration and production of inflammatory mediators

Poly(ADP-ribosyl)ation (PARylation) is a protein modification reaction regulating various diverse cellular functions ranging from metabolism, DNA repair and transcription to cell death. We set out to investigate the role of PARylation in wound healing, a highly complex process involving various cellular and humoral factors. We found that topically applied poly[ADP-ribose] polymerase (PARP) inhibitors 3-aminobenzamide and PJ-34 accelerated wound closure in a mouse model of excision wounding. Moreover, wounds also closed faster in PARP-1 knockout mice as compared with wild-type littermates. Immunofluorescent staining for poly(ADP-ribose) (PAR) indicated increased PAR synthesis in scattered cells of the wound bed. Expression of interleukin (IL)-6, tumor necrosis factor (TNF)-α, inducible nitric oxide synthase and matrix metalloproteinase-9 was lower in the wounds of PARP-1 knockout mice as compared with control, and expression of IL-1β, cyclooxygenase-2, TIMP-1 and -2 also were affected. The level of nitrotyrosine (a marker of nitrating stress) was lower in the wounds of PARP-1 knockout animals as compared with controls. In vitro scratch assays revealed significantly faster migration of keratinocytes treated with 3-aminobenzamide or PJ34 as compared with control cells. These data suggest that PARylation by PARP-1 slows down the wound healing process by increasing the production of inflammatory mediators and nitrating stress and by slowing the migration of keratinocytes.

Neuroprotective effect of EGb761® and low-dose whole-body γ-irradiation in a rat model of Parkinson's disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder after Alzheimer's disease. The present study was undertaken to investigate the pretreatment effects of standardized Ginkgo biloba extract (EGb761(®)) and low-dose whole-body γ-irradiation on the neurological dysfunction in the reserpine model of PD. Male Wistar rats were pretreated orally with EGb761 or fractionated low-dose whole-body γ-irradiation or their combination, then subjected to intraperitoneal injection of reserpine (5 mg/kg body weight) 24 h after the final dose of EGb761 or radiation. Reserpine injection resulted in the depletion of striatal dopamine (DA) level, increased catalepsy score, increased oxidative stress indicated via depletion of glutathione (GSH), increased malondialdehyde (MDA) and iron levels, decreased DA metabolites metabolizing enzymes; indicated by inhibition by glutathione-S-transferase, and nicotinamide adenine dinucleotide phosphate (NADPH)-quinone oxidoreductase (NQO) activities, mitochondrial dysfunction; indicated by declined complex I activity, and adenosine triphosphate (ATP) level and increased apoptosis; indicated by decreased mitochondrial B cell lymphoma-2 (Bcl-2) protein level and by transmission electron microscope. EGb761 and low-dose γ-radiation ameliorated the reserpine-induced state of oxidative stress, mitochondrial dysfunction, and apoptosis in brain. It can be concluded that EGb761, a widely used herbal medicine and low dose of γ-irradiation have protective effects for combating Parkinsonism possibly via replenishment of GSH levels.

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.

The effects of celecoxib, a COX-2 selective inhibitor, on acute inflammation induced in irradiated rats

The potential value of selective and non-selective COX-2 inhibitors in preventing some of the biochemical changes induced by ionizing radiation was studied in rats exposed to carrageenan-induced paw edema and 6-day-old air pouch models. The animals were exposed to different exposure levels of gamma-radiation, namely either to single doses of 2 and 7.5 Gy or a fractionated dose level of 7.5 Gy delivered as 0.5 Gy twice weekly for 7.5 weeks. The inflammatory response produced by carrageenan in irradiated rats was markedly higher than that induced in non-irradiated animals, and depended on the extent of irradiation. Celecoxib, a selective COX-2 inhibitor, in doses of 3, 5, 10, and 15 mg/kg was effective in reducing paw edema in irradiated and non-irradiated rats in a dose-dependent manner as well as diclofenac (3 mg/kg), a non-selective COX inhibitor. Irradiation of animals before the induction of the air pouch by an acute dose of 2 Gy led to a significant increase in leukocytic count, as well as in the level of interleukin-6 (IL-6), interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), LTB(4), PGE(2) (as an index of COX-2 activity), TXB(2) (as an index of COX-1 activity), and the plasma level of MDA. This increase in level of these parameters was more marked than that observed in the non-irradiated animals subjected to the inflammagen. The blood GSH level was not affected by the dose of irradiation used, whereas superoxide dismutase (SOD) activity was suppressed. In many respects, celecoxib (5 mg/kg) was as potent as diclofenac in decreasing the elevated levels of IL-6, IL-1beta, TNF-alpha, LTB(4), PGE(2), but lacked any significant effect on TXB(2) level. Since it is mostly selective for COX-2 with a rare effect on COX-1 enzyme, both drugs at the selected dose levels showed no effect on level of MDA, GSH, and SOD activity.

Mechanisms involved in the anti-inflammatory effect of a standardized willow bark extract

A standardized willow bark extract (STW 33-I) has been examined to clarify its possible mechanism of action as an anti-inflammatory agent. Various facets have been investigated in two inflammation models: the 6-day air pouch model in rats, representing the acute state and the adjuvant induced arthritis representing the chronic one. Parameters included leukocytic infiltration, levels of cytokines and prostanoids in blood, and effects on cyclo-oxygenase (COX)-1 and/or COX-2 enzymes as well as effects involving free radical production. The effect of the extract was compared at two dose levels with comparable anti-inflammatory doses of acetylsalicylic acid (CAS 50-78-2, ASA) as a non-selective COX inhibitor, and celecoxib (CAS 169590-42-5) as a selective COX-2 inhibitor. On a mg/kg basis, the extract was at least as effective as ASA in reducing inflammatory exudates and in inhibiting leukocytic infiltration as well as in preventing the rise in cytokines, and was more effective than ASA in suppressing leukotrienes, but equally effective in suppressing prostaglandins. On COX-2, STW 33-I was more effective than ASA. The present findings show that STW 33-I significantly raises GSH (reduced glutathione) levels, an effect which helps to limit lipid peroxidation. The extract was more potent than either ASA or celecoxib. Higher doses of the extract also reduced malondialdehyde levels and raised shows definite superiority to either ASA or celecoxib in protecting the body against oxidative stress. It is therefore evident that STW 33-I is at least as active as ASA on all the parameters of inflammatory mediators measured, when both are given on a similar mg/kg dose. Considering, however, that the extract contains only 24% salicin (molecular weight 286.2), while ASA has a molecular weight of 180.3, it follows that on a molar basis of salicin vs salicylate, the extract contains less than a sixth of the amount of salicin as the amount of salicylate in ASA. Thus it appears that STW 33-I with its lower "salicin" content than an equivalent dose of ASA, is at least as active as ASA on the measured parameters, a fact that leads one to speculate that other constituents of the extract contribute to its overall activity. The presence of polyphenols in STW 33-I probably plays a significant role in enhancing its free radical scavenging properties. The fact that STW 33-I was superior to ASA in this respect would suggest that the extract may have a better anti-inflammatory effect than ASA on a weight to weight basis, with possibly less side effects.

Mechanisms involved in the gastro-protective effect of STW 5 (Iberogast) and its components against ulcers and rebound acidity

The protective effect of a commercial preparation (STW 5, Iberogast), containing the extracts of bitter candy tuft, lemon balm leaf, chamomile flower, caraway fruit, peppermint leaf, liquorice root, Angelica root, milk thistle fruit and greater celandine herb, against the development of gastric ulcers was previously reported in an earlier publication (Khayyal et al., 2001). All extracts produced a dose dependent anti-ulcerogenic effect associated with a reduced acid output, an increased mucin secretion, an increase in prostaglandin E(2) release and a decrease in leukotrienes. The effect on pepsin content was not uniform and did not seem to bear a relationship with the anti-ulcerogenic activity. The best effects were observed with the combined formulation, STW 5. Furthermore, the effect of the latter in protecting against the development of rebound gastric acidity was examined experimentally in rats and compared with the effect of some commercial antacid preparations (Rennie, Talcid and Maaloxan). A model of testing rebound acidity was developed by inducing a marginal increase in gastric acidity through the administration of indomethacin, in such a way that it could be easily neutralized, allowing any eventual secondary increase in acidity to be measured within a few hours of administration. In addition, the serum gastrin level was measured after drug treatment to establish any correlation between it and any rebound acidity. The results obtained demonstrated that STW 5 did not only lower the gastric acidity as effectively as the commercial antacid, but it was more effective in inhibiting the secondary hyperacidity. Moreover, STW 5 was capable of inhibiting the serum gastrin level in rats, an effect which ran parallel to its lowering effect on gastric acid production.