Influence of heme and heme oxygenase-1 transfection of pulmonary microvascular endothelium on oxidant generation and cGMP

The protective effect of crocin against testicular toxicity induced by ionizing radiation via AKT/FOXO pathway

Crocin, a pharmacologically active component of Crocus sativus L. (saffron), has been informed to be beneficial in the treatment of stress-related oxidative impairment. In the present study, we examined the protective role of crocin against testicular damage induced by radiation (acute and fractionated) and the alteration of the AKT/FOXO signaling pathway. Male Wister albino rats were exposed to acute dose of 6 Gy and a fractionated dose of gamma radiation (2 Gy every 2 days up to 6 Gy total doses). Rats were pretreated intraperitoneally with crocin in a dose of 50 mg/kg for seven consecutive days prior to exposure to irradiation at a level of 6 Gy and during the fractionated irradiation of rats. Control groups were run concurrently. Ionizing radiation caused changes in the level of oxidative stress biomarkers manifested as elevation of thiobarbituric acid reactive substance, total nitrate/nitrite and reactive oxygen species (ROS) associated with a decrease in catalase as well as in the level of inflammatory parameters (decrease in expression of Nrf2 which was related to a significant increase in expression of NF-κB p65). Irradiation produced cellular damage characterized by an increase in serum lactate dehydrogenase. These findings were aligned with increased expression of the forkhead box O-1 (FOXO-1) and activation of protein kinase B (AKT) pathway. Irradiation of rats led to reduction in serum testosterone level and testicular weights. Pretreatment with the indicated dose of crocin shielded against the changes in all the evaluated parameters. Administration of crocin can be introduced as a novel preclinical approach for regulation of testicular damage induced by radiation; via controlling the ongoing oxidative stress and inflammatory reaction as well as activation FOXO/AKT signaling pathway.

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.

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.

New thiophene derivative augments the antitumor activity of γ-irradiation against colorectal cancer in mice via anti-inflammatory and pro-apoptotic pathways

BACKGROUND

Colorectal cancer (CRC) is one of the most common types of cancer worldwide and the second cause of cancer-related deaths. It usually starts as an inflammation that progresses to adenocarcinoma. The goal of the present study was to investigate the antitumor efficacy of a new thiophene derivative against CRC in mice and explore the possible associated molecular pathways. The potential of this thiophene derivative to sensitize the CRC tumor tissue to a low dose of gamma irradiation was also investigated.

METHODS

Adult male mice were divided into seven groups; control, group treated with dimethylhydrazine (DMH) for the induction of CRC. The DMH-group was further divided into six groups and treated with either cisplatin, thiophene derivative, γ-irradiation, cisplatin + γ-irradiation, thiophene derivative + γ-irradiation, or left untreated.

RESULTS

DMH induced CRC as evidenced by the macroscopic examination of colon tissues and histopathology, and elevated the activities of cyclooxygenase2 (COX2) and nitric oxide synthase (iNOS). DMH also elevated kirsten rat sarcoma (KRAS) and downregulated the peroxisome proliferator activated receptor (PPARγ) as shown by RT-PCR and Western blotting. DMH exerted anti-apoptotic activity by reducing the expression of phosphorylated p53 and cleaved caspase3 at the gene and protein levels. The flow cytometry analysis showed that DMH elevated the necrosis and reduced the apoptosis compared to the other groups. The colon tissue from DMH-treated mice showed hyperplasia, aberrant crypt foci, loss of cell polarity, typical CRC of grade 4 with lymphocytes and macrophages infiltrating mucosa, muscularis mucosa, and submucosa score 3. Treatment with thiophene derivative or γ-irradiation ameliorated most of these deleterious effects of DMH. The concomitant action of thiophene derivative + γ-irradiation was typified by the better amelioration of tumor incidence and multiplicity, iNOS, PPARγ, p53, caspase 3, and histopathology of colon.

CONCLUSION

Taken together, the new thiophene derivative is a promising therapeutic candidate for treatment of colorectal cancer in mice. It also sensitizes the CRC tumor to the ionizing radiation through anti-inflammatory and pro-apoptotic pathways.

Boswellic acid protects against Bisphenol-A and gamma radiation induced hepatic steatosis and cardiac remodelling in rats: role of hepatic PPAR-α/P38 and cardiac Calcineurin-A/NFATc1/P38 pathways

Bisphenol-A (BPA) and gamma-radiation are two risky environmental pollutants that human beings are exposed to in everyday life and consequently they threaten human health via inducing oxidative stress, inflammation, and eventually tissue damage. This study aims at appraising the protective effect of Boswellic Acid (BA) (250 mg/kg/day, orally) administration on BPA (150 mg/kg/day, i.p) and γ-irradiation (IR) (3 Gy/week for 4 weeks up to cumulative dose of 12 Gy/experimental course) for 4 weeks-induced damage to liver and heart tissues of rats. The present results indicated a significant improvement against damage induced by BPA and IR revealed in biochemical investigations (hepatic PPAR-α/P38 and cardiac ET-1/Calcineurin-A/NFATc1/P38) and histopathological examination of liver and heart. It could be concluded that BA possesses a protective effect against these two deleterious environmental pollutants which attracted major global concerns due to their serious toxicological impact on human health.

Withania somnifera (Ashwagandha) root extract counteract acute and chronic impact of γ-radiation on liver and spleen of rats

The exposure to ionizing radiation has become inescapably because of increased dependence on radiation to execute works in different fields and also its influences on biological systems. Thus, the current study aimed at examination of the radio-protective effect of the natural ashwagandha (Ag) against acute and chronic doses of γ-radiation on liver and spleen of rats. The impact of Ag was inspected in rats exposed to acute exposure of 8 Gy (single dose) or to chronic exposure of 8 Gy (2 Gy every other day for 4 times). The data obtained reveals significant amelioration of the redox status (MDA, GSH and ROS) in spleen and liver tissues of rats treated with Ag and exposed to the 2-different modes of γ-radiation. Besides, the changes in inflammatory responses assessed by measurements of IL-17, IL-10 and α7-nAchR are less pronounced in rats received Ag and γ-radiation compared to irradiated rats. Further, the measurements of tissues structural damage markers (MMP-2, MMP-9 and TIMP-1) pointed to benefit of Ag against γ-radiation. The histopathological investigation of spleen and liver tissues confirmed this ameliorating action of Ag counter to γ-radiation hazards. It could be suggested that Ashwagandha could exerts radio-protective influences because of its antioxidants and anti-inflammatory capabilities.

Canagliflozin, a SGLT-2 inhibitor, relieves ER stress, modulates autophagy and induces apoptosis in irradiated HepG2 cells: Signal transduction between PI3K/AKT/GSK-3β/mTOR and Wnt/β-catenin pathways; in vitro

Background and Objectives

Metabolic shifting from mitochondrial respiration to glycolysis characterizes malignant cells from its normal counterparts and is attributed to overactivation of oncogenic signaling pathways. Hence, this study intended to investigate the influence of canagliflozin (CAN) and/or γ-irradiation (γ-IR) on HepG2 cell proliferation, crosstalk between phosphatidylinositol 3-kinases (PI3K)/AKT/glycogen synthase kinase-3-β (GSK3-β)/mTOR and Wnt/β-catenin signaling pathways, and their regulation of diverse processes, such as endoplasmic reticulum (ER) stress, autophagy, and apoptosis.

Materials and Methods

HepG2 cells were treated with different doses of CAN and then exposed to different doses of γ-IR to achieve optimization that was based on cytotoxicity and clonogenic assays, respectively. The effects of CAN and/or γ-IR on glycolytic metabolism, cellular bioenergetics, oxidative stress, ER stress and autophagy biomarkers, expression of PI3K/AKT/GSK3-β/mTOR and Wnt/β-Catenin signaling pathways, and apoptotic markers were monitored.

Results

CAN enhanced the antitumor potential of γ-IR as displayed by a significant inhibition of clonogenic survival in HepG2 cells via inhibition of glucose uptake, lactate release, and modulation of ER stress-mediated autophagy; switched it to apoptosis; as well as disabled signaling pathways which contribute to metabolic reprogramming and tumor progression induced by γ-IR that confer radioresistance and treatment failure.

Conclusion

Our study sheds light on the effective combination of CAN and γ-IR in hepatocellular carcinoma treatment and necessitates CAN treatment prior to γ-IR to overcome metabolic reprogramming-associated radioresistance and improve curative outcomes.

Roles of Simvastatin and Sildenafil in Modulation of Cranial Irradiation-Induced Bystander Multiple Organs Injury in Rats

In radiobiology and radiation oncology fields, the observation of a phenomenon called radiation-induced bystander effect (RIBE) has introduced the prospect of remotely located tissues' affection. This phenomenon has been broadly developed to involve the concept of RIBE, which are relevant to the radiation-induced response of a distant tissue other than the irradiated one. The current study aimed at investigating each of the RIBE of cranial irradiation on oxidative and inflammatory status in different organs such as liver, kidney, heart, lung, and spleen. Being a vital target of the cholinergic anti-inflammatory response to an inflammatory stimulus, the splenic α-7-nicotinic acetylcholine receptor (α-7nAchR) was evaluated and the hepatic contents of thioredoxin, peroxisome proliferator-activated receptor-alpha and paraoxinase-1 (Trx/PPAR-α/PON) were also assessed as indicators for the liver oxidative stress and inflammatory responses. Being reported to act as antioxidant and anti-inflammatory agents, simvastatin (SV) and/or sildenafil (SD) were investigated for their effects against RIBE on these organs. These objectives were achieved via the biochemical assessments and the histopathological tissues examinations. Five experimental groups, one sham irradiated and four irradiated groups, were exposed to cranial irradiation at dose level of 25 Gy using an experimental irradiator with a Cobalt (Co60) source, RIBE, RIBE + SV (20 mg.(kg.bw)-1 day-1), RIBE + SD (75 mg.(kg.bw)-1 day-1), and RIBE + SV + SD. Cranial irradiation induced structural, biochemical, and functional dys-regulations in non-targeted organs. RIBE-induced organs' injuries have been significantly corrected by the administration of SV and/or SD. Our results suggest the possibility of a potentiated interaction between SV and SD in the modulation of the RIBE associated with head and neck radiotherapy.

Influence of Ce3+ Substitution on Antimicrobial and Antibiofilm Properties of ZnCexFe2-xO4 Nanoparticles (X = 0.0, 0.02, 0.04, 0.06, and 0.08) Conjugated with Ebselen and Its Role Subsidised with γ-Radiation in Mitigating Human TNBC and Colorectal Adenocarcinoma Proliferation In Vitro

Cancers are a major challenge to health worldwide. Spinel ferrites have attracted attention due to their broad theranostic applications. This study aimed at investigating the antimicrobial, antibiofilm, and anticancer activities of ebselen (Eb) and cerium-nanoparticles (Ce-NPs) in the form of ZnCexFe2-XO4 on human breast and colon cancer cell lines. Bioassays of the cytotoxic concentrations of Eb and ZnCexFe2-XO4, oxidative stress and inflammatory milieu, autophagy, apoptosis, related signalling effectors, the distribution of cells through the cell-cycle phases, and the percentage of cells with apoptosis were evaluated in cancer cell lines. Additionally, the antimicrobial and antibiofilm potential have been investigated against different pathogenic microbes. The ZOI, and MIC results indicated that ZnCexFe2-XO4; X = 0.06 specimen reduced the activity of a wide range of bacteria and unicellular fungi at low concentration including P. aeruginosa (9.5 mm; 6.250 µg/mL), S. aureus (13.2 mm; 0.390 µg/mL), and Candida albicans (13.5 mm; 0.195 µg/mL). Reaction mechanism determination indicated that after ZnCexFe2-xO4; X = 0.06 treatment, morphological differences in S.aureus were apparent with complete lysis of bacterial cells, a concomitant decrease in the viable number, and the growth of biofilm was inhibited. The combination of Eb with ZFO or ZnCexFe2-XO4 with γ-radiation exposure showed marked anti-proliferative efficacy in both cell lines, through modulating the oxidant/antioxidant machinery imbalance, restoring the fine-tuning of redox status, and promoting an anti-inflammatory milieu to prevent cancer progression, which may be a valuable therapeutic approach to cancer therapy and as a promising antimicrobial agent to reduce the pathogenic potential of the invading microbes.

Fucoxanthin alters the apelin-13/APJ pathway in certain organs of γ-irradiated mice

Apelin-13 and APJ are implicated in different key physiological processes. This work aims at exploring the radioprotective effect of fucoxanthin (FX) on γ-radiation (RAD)-induced changes in the apelin-13/APJ pathway, which causes damage in the liver, kidney, lung and spleen of mice. Mice were administered FX (10 mg kg-1 day-1, i.p) and exposed to γ-radiation (2.5 Gy week-1) for four consecutive weeks. The treatment of irradiated mice by FX resulted in a significant amendment in protein expression of the apelin-13/APJ/NF-κB signalling pathway concurrently with reduced hypoxia (hypoxia-inducible factor-1α), suppressed oxidative stress marker (malondialdehyde), enhanced antioxidant defence mechanisms (reduced glutathione and glutathione peroxidase), a modulated inflammatory response [interleukin-6 (IL-6), monocyte chemoattractant protein-1, IL-10 and α-7-nicotinic acetylcholine receptor) and ameliorated angiogenic regulators [matrix metalloproteinase (MMP-2), MMP-9 and tissue inhibitor of metalloproteinase-1), as well as the tissue damage indicator (lactate dehydrogenase) in organ tissues. In addition, there were significant improvement in serum inflammatory markers tumour necrosis factor-α, IL-10, IL-1β and C-reactive protein compared with irradiated mice. The histopathological investigation of the FX + RAD organ tissues support the biochemical findings where the improvements in the tissues' architecture were obvious when compared with those of RAD. FX was thus shown to have a noticeable radioprotective action mediated through its regulatory effect on the apelin-13/APJ/NF-κB signalling pathway attributed to its antioxidant and anti-inflammatory activity that was reflected in different physiological processes. It could be recommended to use FX in cases of radiation exposure to protect normal tissues.

The impact of citicoline on brain injury in rats subjected to head irradiation

Hazard and risk associated with the use of radiotherapy play a crucial role in brain injury with interference via the neuroendocrine activity of the cancer survivors, and there is no effective preventive strategy. We conducted this study to assess the effect of citicoline in biosynthesis variants occurring in the cerebral cortex of rats in response to head γ-irradiation. Bio-analysis includes MDA, 8-OHdG, and NO as oxidation indicators; total antioxidant activity; the inflammatory factors TNF-α, IL-1β, and amyloid-β 42 levels; the caspase-3 cell death marker; IGF-I; serum hormones including GH, ACTH, FSH, and LH; and the neurotransmitters acetylcholine, dopamine, and serotonin. We exposed animals to 10 Gy head gamma irradiation followed by citicoline treatment and sustained for 30 days. The animals were sacrificed at the 3rd and 30th day post-irradiation. Citicoline mechanism has been linked to potent radical reduced ability counteracting the oxidative stress-mediated inflammation and apoptosis. Citicoline treatment has normalized the altering recorded in serum hormones associated with a significant modulation in the levels of IGF-1/PI3K/AKT factors. Such improvements have been concomitant with regulated neurotransmitter levels. We could conclude that citicoline may safely be supplemented to avoid both short- and long-term damages to the neuroendocrine disturbances, oxidative stress, inflammation, and apoptosis induced by head irradiation.

Piceatannol promotes hepatic and renal AMPK/SIRT1/PGC-1α mitochondrial pathway in rats exposed to reserpine or gamma-radiation

Human exposure to radio-therapeutic doses of gamma rays can produce late effects, which negatively affect cancer patients' quality of life, work prospects, and general health. This study was performed to explore the role of Piceatannol (PIC) in the process of "mitochondrial biogenesis" signaling pathway as possible management of disturbances induced in stressed animal model(s) either by gamma-irradiation (IR) or administration of reserpine (RES); as a mitochondrial complex-I inhibitor. PIC (10 mg/kg BW/day; orally) were given to rats for 7 days, after exposure to an acute dose of γ-radiation (6 Gy), or after a single reserpine injection (1 g/kg BW; sc). Compared to reserpine or γ-radiation, PIC has attenuated hepatic and renal mitochondrial oxidative stress denoted by the significant reduction in the content of lipid peroxides and NO with significant induction of SOD, CAT, GSH-PX, and GR activities. PIC has also significantly alleviated the increase of the inflammatory markers, TNF-α and IL-6 and apoptotic markers, cytochrome c, and caspase-3. The decrease of oxidative stress, inflammation, and apoptotic responses were linked to a significant amelioration in mitochondrial biogenesis demonstrated by the increased expression and proteins' tissue contents of SIRT1/p38-AMPK, PGC-1α signaling pathway. The results are substantiated by the significant amelioration in mitochondrial function verified by the higher levels of ATP content, and complex I activity, besides the improvement of hepatic and renal functions. Additionally, histopathological examinations of hepatic and renal tissues showed that PIC has modulated tissue architecture after reserpine or gamma-radiation-induced tissue damage. Piceatannol improves mitochondrial functions by regulating the oxidant/antioxidant disequilibrium, the inflammatory and apoptotic responses, suggesting its possible use as adjuvant therapy in radio-therapeutic protocols to attenuate hepatic and renal injuries.

Modulatory effect of methylsulfonylmethane against BPA/γ-radiation induced neurodegenerative alterations in rats: Influence of TREM-2/DAP-12/Syk pathway

AIMS

Methylsulfonylmethane (MSM), is an organosulfur compound, has many health benefits. Bisphenol-A (BPA) and γ-radiation (R) are two risky environmental contaminants that human beings are exposed to in everyday life. This work aims at unveiling the modulatory role of MSM in combating BPA and R co-exposure induced neurodegenerative disorder (Alzheimer's (AD)-mimic neurotoxicity).

MAIN METHODS

Female rats were randomly divided into five groups. One group was normal control and the other four groups were subjected to subacute BPA intoxication and/or exposed to fractionated weekly doses of R for 4 weeks and either untreated or treated with MSM concomitantly.

KEY FINDINGS

BPA and R co-exposure induced typical hallmarks of neurodegenerative disorders as revealed by tremendously elevated oxidative stress, extensive neuroinflammation (tumor necrosis factor -α and interleukin-1β), elevated AD markers (amyloid-beta (Aβ₄₂), acetylcholinesterase (AchE) activity and tau-phosphorylation) in cortex and hippocampus as well as up-regulation of microglial pro-inflammatory triggering receptor expressed on myeloid cell-2(TREM-2)/DNAX-activating protein of 12 kDa (DAP-12)/spleen-tyrosine kinase (Syk) pathway and its downstream targets (PLC-γ/DAG/p38-MAPK) in hippocampus. Also, neurodegenerative lesions were revealed in histopathological examination of cortex and hippocampus coupled with marked Aβ deposition in hippocampus. Whereas, MSM treatment improved histopathological insults and ameliorated level of oxidative stress, neuroinflammation and AD markers as well as modulated TREM-2/DAP-12/Syk pathway.

SIGNIFICANCE

Our data suggest that MSM afforded neuroprotection against BPA and R; supporting its potential application in the associated neurodegenerative disorders.

Cavernosal hydrogen sulfide levels are associated with nitric oxide and hemeoxygenase levels in diabetic rats

Penile erection is a neuromuscular event modulated by psyche, hormones as well as neurotransmitters. This pre-clinical study aimed to assess hydrogen sulfide (H₂S) relationship with nitric oxide (NO) and hemeoxygenase (HO) in the cavernous tissues of diabetic rats. Overall, 90 adult male rats were investigated (6 groups, n = 15 each). They were subdivided into the following groups; untreated rats, rats treated with H₂S donor/inhibitor, induced diabetic rats, diabetic rats treated with H₂S donor/inhibitor. At the 6th week, the rats were killed to assess cavernous tissue cGMP, NO, H₂S, HO enzyme activity levels. The rats treated with H₂S donor showed increased mean cavernous tissue cGMP, NO, H₂S, and HO enzyme activity levels whereas induced diabetic rats and rats treated with H₂S inhibitor showed significant decreases in these parameters compared with the untreated rats. On the other hands, diabetic rats treated with H₂S donor showed elevated mean cavernous tissue cGMP, NO, H₂S, and HO enzyme activity levels whereas diabetic rats treated with H₂S inhibitor showed significant decreases in these parameters compared with diabetic rats. Cavernous tissue H₂S levels exhibited significant positive correlations with the cavernous tissue levels cGMP, NO, and HO enzyme activity levels. From these results, it could be concluded that cavernous tissues H₂S plays a role of male sexual health by affecting cavernous tissues NO and HO enzyme activity in general and in diabetics in particular.

Protective effect of rutin against brain injury induced by acrylamide or gamma radiation: role of PI3K/AKT/GSK-3β/NRF-2 signalling pathway

This study was designed to evaluate the effect of rutin on PI3K/AKT-signalling in case of acrylamide or γ-radiation-induced neurotoxicity. To induce brain damage, animals were received acrylamide (25 mg/kg b.wt./orally/day) or 5 Gy of γ-radiation exposure accompanied with an administration of rutin (200 mg/kg b.wt./orally/day). Our data revealed that, compared to acrylamide or γ-radiation, rutin activated PI3K/AKT/GSK-3β/NRF-2-pathway through increased protein levels of p-PI3K, p-AKT and p-GSK-3β and up-regulated the expression of NRF-2. This was achieved by modulating MDA, GST, IL-1β, IL-6 and reduced the interference of ROS with IGF-1 and NGF stimulating the PI3K/AKT-signaling. Furthermore, histopathological examinations of brain tissues showed that rutin has modulated tissue architecture after acrylamide or γ-radiation induced tissue damage. It could be concluded that rutin provides protection effect against acrylamide or γ-radiation-induced neurotoxicity via activation of the PI3K/AKT/GSK-3β/NRF-2-pathway by altering the phosphorylation state through its ability to scavenge free radicals generation, modulating gene expression and its anti-inflammatory effects.

Cholinergic and cytoprotective signaling cascades mediate the mitigative effect of erythropoietin on acute radiation syndrome

The present investigation aimed to evaluate the radiomitigative efficacy of the recombinant human erythropoietin (EPO) against acute radiation syndrome (ARS) in a rat model. Rats were irradiated with a single sublethal dose of γ-radiation (7 Gy; total body irradiation; TBI) on the 1st day of experimental course, then received EPO (5000 IU/kg; i.p.) 24 h after irradiation, and rats were observed for 30 days of survival analysis. Administration of EPO improved 30-day survival, alleviated TBI-induced myelosuppression and pancytopenia, by augmenting lymphocytes and other white blood cells in the peripheral blood of rats, while bone marrow and spleen cellularity were restored. EPO post-exposure treatment alleviated hepatotoxicity biomarkers and restored splenic function. EPO abrogated radiation-induced oxidative stress through the upregulation of the cholinergic anti-inflammatory nicotinic acetylcholine receptor (α-7-nAChR) and the pro-survival Janus kinase-2 and signal transducers and activators of transcription JAK-2/STAT-3 signaling mediated via enhancing nuclear factor erythroid-2 related factor-2 (Nrf-2) cytoprotective machinery in liver and spleen of irradiated rats. Moreover, EPO treatment prevented hepatic and splenic apoptosis. The present study establishes the implication of α-7-nAChR-JAK-2/STAT-3-Nrf-2 signaling cascade in the radiomitigative potential of EPO against ARS.

Gallium Nanoparticle-Mediated Reduction of Brain Specific Serine Protease-4 in an Experimental Metastatic Cancer Model

Purpose:

Tumor growth and metastasis depend on angiogenesis; therefore, efforts are being made to develop specific angiogenic inhibitors. Gallium (Ga) is the second most common metal ion, after platinum, used in cancer treatment. Its activities are numerous and various. In the present study, we aimed to investigate the effect of Ga on brain metastasis arising from hepatocellular carcinoma (HCC).

Materials and methods:

Forty experimental rats (divided into 4 groups) received diethylnitrosamine (DEN) at a dose (20 mg/kg.b.wt.; for 6 weeks) to induce HCC and were treated with Ga nanoparticles (GaNPs) with the bacterium Bacillus licheniformis (1mg/kg.b.wt.). Liver functions (alanine aminotransferase; (ALT), aspartate aminotransferase; (AST) and gamma glutamyl transferase; (GGT) and alpha-fetoprotein (AFP)) were assessed with histopathological examination of liver sections to confirm the induction of HCC. In addtion, brain-specific serine protease 4 (BSSP4), extracellular signal-regulated kinase (ERK), a microtubule-associated protein (Tau), vascular endothelial growth factor (VEGF), vascular cells adhesion molecule-1 (VCAM-1), cytochrome P450 (CYP450), lipid peroxidation (MDA) and glutathione-S-transferase (GST) were measured in brain tissue.

Results:

GaNPs ranged from 5 to 7 nm. HCC was confirmed by elevation in liver enzymes and AFP. Additionally, histopathological examination of liver showed focal area of anaplastic hepatocytes with other cells forming acini associated with fibroblastic cell proliferation. In brain, compared to the DEN alone group, we found that GaNPs modulated brain metastasis by reducing CYP450 and BSSP4 mRNA, and protein expression of p-ERK and p-Tau, and angiogenesis mediators (VEGF and VCAM-1). Also, GaNPs elevated lipid peroxidation and GST activity.

Conclusion:

It is concluded that GaNPs may prevent metastasis via inhibition of BSSP4 mRNA expression leading to suppression of a variety of growth factors and cell adhesion molecules involved in tumor growth and angiogenesis.

Diosmin attenuates radiation-induced hepatic fibrosis by boosting PPAR-γ expression and hampering miR-17-5p-activated canonical Wnt-β-catenin signaling

BACKGROUND

Liver fibrosis is one of the major complications from upper right quadrant radiotherapy. MicroRNA-17-5p (miR-17-5p) is hypothesized to act as a regulator of hepatic stellate cell (HSCs) activation by activation of the canonical Wnt-β-catenin pathway. Diosmin (Dios), a citrus bioflavonoid, is known to possess potent antioxidant, anti-inflammatory, and anti-apoptotic properties.

PURPOSE

To explore the molecular mechanisms that underlie radiation-induced liver fibrosis, and to evaluate the possible influence of Dios on the miR-17-5p-Wnt-β-catenin signaling axis during fibrogenesis provoked by irradiation (IRR) in rats. Also, the effect of Dios on hepatic peroxisome proliferator activated receptor-γ (PPAR-γ) expression as a regulator for HSC activation was considered.

METHODS

We administered 100 mg·(kg body mass)^-1·day^-1 (per oral) of Dios were administered to IRR-exposed rats (overall dose of 12 Gy on 6 fractions of 2 Gy each) for 6 successive weeks.

RESULTS

Data analysis revealed that Dios treatment mitigated oxidative stress, enhanced antioxidant defenses, alleviated hepatic inflammatory responses, abrogated pro-fibrogenic cytokines, and stimulated PPAR-γ expression. Dios treatment repressed the miR-17-5p activated Wnt-β-catenin signaling induced by IRR. Moreover, Dios treatment restored the normal hepatic architecture and reversed pathological alterations induced by IRR.

CONCLUSION

We hypothesize that the stimulation of PPAR-γ expression and interference with miR-17-5p activated Wnt-β-catenin signaling mediates the antifibrotic properties of Dios.

Boswellic acid disables signal transduction of IL-6-STAT-3 in Ehrlich ascites tumor bearing irradiated mice

Boswellic acid (BA) is known for its ability to trigger apoptosis as well as to inhibit angiogenesis in tumor tissue. In this study, we investigated the effect of BA on the IL-6-STAT-3 signalling pathway in irradiated mice bearing solid tumors of Ehrlich ascites carcinoma (EAC). For this, we administered BA (25 mg·(kg body mass)(-1)·day(-1), by intraperitoneal injection) to mice with EAC, and then exposed them to 4 Gy of gamma radiation. Data analyses of the results revealed a specific impact from BA on IL-6R mRNA and survivin mRNA in EACs and irradiated EAC-bearing mice. Also, significant improvements were observed in the protein expression of JAK-1, P-JAK-1, STAT-3, P-STAT-3, and caspase-3, as well as VEGF and IL-6 levels. We propose that BA interfered with IL-6-STAT-3 signal transduction, thereby preventing the activation of caspase-3 and subsequently triggering the process of apoptosis. However, the alternative angiogenesis pathway, which includes the over-expression of VEGF and which depends on IL-6-STAT-3 signalling, was inhibited by the action of BA. Thus, we recommend that therapeutic strategies for cancer should include treatment with BA.

Effect of periodontitis on erectile function and its possible mechanism

INTRODUCTION

Periodontitis is one of the important risk factors resulting in cardiovascular diseases. Erectile dysfunction (ED) is strongly correlated with cardiovascular diseases. The expression of endothelial nitric oxide synthase (eNOS) in penile tissue has an important role in the mechanism of erection.

AIM

To investigate the effect of periodontitis on erectile function and the possible mechanism.

METHODS

After induction of periodontitis in rat, the ratio of maximum intracavernosal pressure/mean arterial pressure (ICPmax /MAP)×100, the expression of eNOS in penile tissue, the level of serum C-reactive protein (CRP) and tumor necrosis factor-α (TNF-α), and the ultrastructural changes of the cavernous tissue were examined and compared between periodontitis rats (group A) and control rats (group B).

MAIN OUTCOME MEASURE

Periodontitis significantly decrease not only the ICPmax/MAP×100 and the expression of eNOS but also the activity of NOS and the level of cyclic guanosine monophosphate (cGMP) in cavernous tissue of rat.

RESULTS

After electrostimulation by 3 and 5 voltage, the ratio of ICPmax /MAP×100 in group A was significantly less than that in group B (19.54±6.16 vs. 30.45±3.12; 30.91±5.61 vs. 50.52±9.52, respectively; P<0.05).The level of serum CRP and TNF-α in group A is significantly higher in group B (P<0.05).The quantitative real-time reverse transcription polymerase chain reaction study demonstrated no statistically significant difference in the expression of mRNA of eNOS in cavernous tissue between the two groups (P>0.05). But there was significant decrease in eNOS protein of the cavernous tissue in group A than in group B (P<0.05). Total NOS activity and cGMP level in cavernosal tissue were significantly lower in group A than in group B (P<0.05). There was no significant alternation occurred in the ultrastructures of penile cavernous tissue.

CONCLUSIONS

The function of penile erection is impaired by periodontitis. The decreased in the expression of eNOS and NOS activity in penile cavernous tissue caused by mild systemic inflammatory status in periodontitis may be one of the important risk factors of ED.

Inhibition of hypoxic pulmonary vasoconstriction of rats by carbon monoxide

Hypoxic pulmonary vasoconstriction (HPV), a unique response of pulmonary circulation, is critical to prevent hypoxemia under local hypoventilation. Hypoxic inhibition of K(+) channel is known as an important O(2)-sensing mechanism in HPV. Carbon monoxide (CO) is suggested as a positive regulator of Ca(2+)-activated K(+) channel (BK(Ca)), a stimulator of guanylate cyclase, and an O(2)-mimetic agent in heme moiety-dependent O(2) sensing mechanisms. Here we compared the effects of CO on the HPV (P(O(2)), 3%) in isolated pulmonary artery (HPV(PA)) and in blood-perfused/ventilated lungs (HPV(lung)) of rats. A pretreatment with CO (3%) abolished the HPV(PA) in a reversible manner. The inhibition of HPV(PA) was completely reversed by 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ), a guanylate cyclase inhibitor. In contrast, the HPV(lung) was only partly decreased by CO. Moreover, the partial inhibition of HPV(lung) by CO was affected neither by the pretreatment with ODQ nor by NO synthase inhibitor (L-NAME). The CO-induced inhibitions of HPV(PA) and HPV(lung) were commonly unaffected by tetraethylammonium (TEA, 2 mM), a blocker of BK(Ca). As a whole, CO inhibits HPV(PA) via activating guanylate cyclase. The inconsistent effects of ODQ on HPV(PA) and HPV(lung) suggest that ODQ may lose its sGC inhibitory action when applied to the blood-containing perfusate.

Effect of HO-1 cDNA-liposome complex transfer on erectile signalling of aged rats

This work aimed to assess the efficacy of haeme oxygenase-1 (HO-1) cDNA-liposome complex transfer as a mediator of erectile signalling in aged rats. One hundred and fifty aged white albino rats were equally divided into five groups: controls, rats receiving lipofectamine, rats receiving intracorporeal HO-1 cDNA-lipsome complex, rats receiving HO-1 cDNA-liposome complex plus nitric oxide synthase (NOS) inhibitor, and rats receiving HO-1 cDNA-liposome complex plus HO inhibitor. Six rats were killed from each group after 12, 24 and 48 h, and after1 and 2 weeks. In dissected cavernous tissues, the following were assessed: HO-1 gene expression, Western blot for HO-1, HO enzyme activity, cGMP and histopathology. The results showed that HO-1 cDNA-liposome complex transfer led to a significant increase in cavernous tissue HO-1 protein, HO-1 gene expression, HO enzyme activity and cGMP up to 1 week. NOS inhibition exhibited no effect on HO-1 gene enhancement of cavernous tissue HO enzyme activity or cGMP, whereas inhibition of HO significantly decreased these parameters. Histopathology of cavernous tissue demonstrated a significant dilatation of helicine arteries in HO-1 cDNA-liposome complex treated group after 48 h compared with the controls. It is concluded that HO-1 cDNA-liposome complex transfer augments cavernous tissue cGMP with subsequent sinusoidal relaxation.

The role of PDE5 inhibitors in heme oxygenase-cGMP relationship in rat cavernous tissues

INTRODUCTION

Heme oxygenase (HO) enzyme catalyzes oxidative degradation of heme to biliverdin and carbon monoxide (CO). CO shares many properties with nitric oxide (NO) including the activation of soluble guanyl cyclase.

AIM

To assess cavernous tissue HO activity and cyclic guanosine monophosphate (cGMP) levels in response to oral phosphodiesterase type 5 (PDE5) inhibitors.

METHODS

Seven hundred twenty male Sprague-Dawley rats, divided into six groups, were investigated. Group 1, controls; group 2 received sildenafil citrate orally; group 3 received vardenafil hydrochloride; and group 4 received tadalafil. Group 5 was subdivided into three equal subgroups, received the same dose of each drug added to the HO inhibitor, Zn protoporphyrin. Group 6 was subdivided into three equal subgroups, received the same dose of each drug added to the NO inhibitor, L-nitroarginine methylester. Eight rats from each group/subgroup were sacrificed at 0.5, 1, 2, 3, 4, 6, 18, 24, and 36 hours, respectively.

MAIN OUTCOME MEASURES

HO enzyme activity assay and cGMP tissue levels in dissected rat cavernous tissues.

RESULTS

Both cavernous tissue HO enzyme activity and cGMP levels were increased significantly in sildenafil-, vardenafil-, and tadalafil-treated rats compared with the controls, with significant decreases after either HO or NO inhibition. Cavernous tissue HO enzyme activity and cGMP showed a positive significant correlation (r = 0.854, P < 0.001).

CONCLUSION

The effects of PDE5 inhibitors in cavernous tissue are partly mediated through HO enzyme activity.

Effect of hemin and carbon monoxide releasing molecule (CORM-3) on cGMP in rat penile tissue

INTRODUCTION

Cyclic guanosine monophosphate (cGMP) levels can be regulated by heme oxygenase-1 and 2 (HO-1 and HO-2)-derived carbon monoxide (CO).

AIMS

Assessment of the effect of upregulating CO in rat corpora cavernosa (CC) on cavernous cGMP.

METHODS

Three experimental groups were studied: first group (N = 40), short-term HO induction over 2 weeks by injection of intraperitoneal increasing doses of hemin; the second group (N = 40) was subjected to intracavernosal injection of CO donor, CORM-3, or its inactive form (iCORM-3) over 2 weeks; the third group (N = 60) was subdivided into three subgroups: the first one received a combined hemin and CORM-3, the second one received hemin and its inhibitor stannus mesoporphyrin (SnMP), and third one received a combined hemin, CORM-3, and SnMP.

MAIN OUTCOME MEASURES

In CC, HO-1 and HO-2 gene expression, Northern blot and Western blot, cGMP levels, and HO enzyme activity.

RESULTS

In the first group, maximum induction of HO-1 gene expression, HO enzyme activity, and cGMP occurred with 4-mg hemin dose with a successive increase over 2 weeks. In the second group, CORM-3 increased cGMP by twofold compared with iCORM-3, and also increased HO-1 protein. In the third group, SnMP inhibited the enhancing effect of CORM-3 and HO on erectile signaling molecules; i.e., HO-1 gene, enzyme activity, and cGMP.

CONCLUSIONS

CORM-3- or hemin-mediated CO release could increase cavernous tissue cGMP.

Heme oxygenase vs. nitric oxide synthase in signaling mediating sildenafil citrate action

INTRODUCTION

Heme oxygenase (HO) enzyme catalyzes the rate limiting step in oxidative degradation of heme to biliverdin and carbon monoxide (CO). CO has been shown to share many properties with nitric oxide (NO), including activation of guanyl cyclase, signal transduction, and gene regulation.

AIM

To assess the signaling pathways mediating cavernous tissues response to sildenafil citrate intake experimentally.

MAIN OUTCOME MEASURES

In dissected cavernous tissues; detection of HO-1, HO-2 and nueronal nitric oxide synthase (nNOS) gene expressions by reverse transcriptase polymerase chain reaction (RT-PCR), HO enzyme activity assay, HO-1, HO-2 protein detection by Western blot, cyclic guanosine monophosphate (cGMP) tissue levels by enzyme linked immunosorbent assay (ELISA) and histopathology.

METHODS

Two hundred forty Sprague-Dawley rats divided into five equal groups were investigated: group (Gr) 1, controls received regular diet; Gr 2, received sildenafil citrate 4 mg/kg orally; Gr 3, received the same dose of sildenafil added to HO inducer, diferuloylmethane; Gr 4, received sildenafil added to HO inhibitor, zinc protoporphyrin, and Gr 5, received sildenafil kg orally by gastric tube. Gr 3 received the same dose of sildenafil added to HO inducer, added to nitric oxide synthase inhibitor, L-Nitroarginine methylester. Twelve rats from each group were sacrificed by cervical dislocation successively after 1/2, 1, 2, and 3 hours from the intake.

RESULTS

HO-2 gene expression was demonstrated in all groups. HO-1 was not expressed in controls, expressed in Gr 2, accentuated in Gr 3, and attenuated in Gr 4 and 5. These results were confirmed by Western blot. The nNOS was expressed in controls, increased in Gr 2 and 3, and decreased in Gr 4 and 5. HO enzyme activity and cGMP levels were significantly elevated in Gr 2, accentuated in Gr 3, and significantly decreased in Gr 4 and 5 compared to controls. Vasodilatations were observed in cavernous tissues of histopathologic sections of Gr 2 and increased in those of Gr 3.

CONCLUSION

Sildenafil citrate actions may be mediated by up-regulation of HO-1 gene expression.

Oral phosphodiesterase-5 inhibitors: effect of heme oxygenase inhibition on cGMP signalling in rat cavernous tissue

This work postulated that heme oxygenase (HO) is partly responsible for controlling phosphodiesterase-5 inhibitor actions by modulating cyclic guanosine monophosphate (cGMP) cavernous tissue levels. Five hundred and four male Sprague-Dawley rats, divided into five groups, were investigated. Group 1 (n=72) included controls, group 2 (n=72) received sildenafil citrate (Viagra) orally, group 3 (n=72) received vardenafil hydrochloride (Levitra), group 4 (n=72) received tadalafil (Cialis). Group 5 (n=216), subdivided into three subgroups (A, B and C, 72 each), received the same dose of each drug with the HO inhibitor, Zn protoporphyrin. Eight rats from each group/subgroup were killed at 0.5, 1, 2, 3, 4, 6, 18, 24 and 36 h when cGMP levels in the cavernous tissues were estimated. Cavernous tissue cGMP levels increased significantly in sildenafil, vardenafil and tadalafil-treated rats compared to the controls with significant decreases after HO inhibition. It is concluded that the effects of these PDE-5 inhibitors in rat cavernous tissue are partly mediated through HO activity via the cGMP signalling pathway.

Ketamine-induced gastroprotection during endotoxemia: role of heme-oxygenase-1

Inducible nitric oxide synthase contributes to lipopolysacharide-induced gastric injury. In contrast, heme-oxygenase-1 has anti-inflammatory effects and is protective against oxidative tissue injury. Ketamine attenuates injury from lipopolysacharide and is associated with changes in oxidative stress proteins, but its effects on the stomach remain to be fully elucidated. We hypothesized that ketamine would diminish gastric injury from lipopolysacharide via down-regulation of nuclear factor-kappass, activator protein-1, and inducible nitric oxide synthase, as well as up-regulation of heme-oxygenase-1. Ketamine up-regulated heme-oxygenase-1 and attenuated lipopolysacharide-induced changes in gastric nuclear factor-kappass, activator protein-1, and inducible nitric oxide synthase. Ketamine negated LPS-induced gastric injury from acidified ethanol, an effect reversed by tin protoporphorin IX. Ketamine diminishes the susceptibility of gastric mucosa to damage from luminal irritants during endotoxemia, which is mediated in part by down-regulation of iNOS and up-regulation of HO-1.

Endothelium-derived microparticles impair endothelial function in vitro

Endothelial cell dysfunction (ECD) is emerging as the common denominator for diverse and highly prevalent cardiovascular diseases. Recently, an increased number of procoagulant circulating endothelial microparticles (EMPs) has been identified in patients with acute myocardial ischemia, preeclampsia, and diabetes, which suggests that these particles represent a surrogate marker of ECD. Our previous studies showed procoagulant potential of endothelial microparticles and mobilization of microparticles by PAI-1. The aim of this study was to test the effects of isolated EMPs on the vascular endothelium. EMPs impaired ACh-induced vasorelaxation and nitric oxide production by aortic rings obtained from Sprague-Dawley rats in a concentration-dependent manner. This effect was accompanied by increased superoxide production by aortic rings and cultured endothelial cells that were coincubated with EMPs and was inhibited by a SOD mimetic and blunted by an endothelial nitric oxide synthase inhibitor. Superoxide was also produced by isolated EMP. In addition, p22(phox) subunit of NADPH-oxidase was detected in EMP. Our data strongly suggest that circulating EMPs directly affect the endothelium and thus not only act as a marker for ECD but also aggravate preexisting ECD.