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.

Immuno-Biochemical Impacts of Gamma Irradiation in Male Rats: A Dose-Response Study

During radiotherapy, immune-modulatory effects of radiation doses should be taken into consideration, not only the anti-tumor radiation effects. Thus, our study aimed to study how γ-radiation modulates immune response in comparison to common immune-suppressive/stimulant agents. Animals were divided into two groups. Category A received Echinacea purpura extract (EP) or irradiated at low radiation doses 0, .25 or .5 Gray (Gy), whereas Category B received cyclophosphamide (CP) or irradiated at high radiation doses 1, 2, or 5 Gy. Serum levels of immunological mediators interleukin-10 (IL-10) and tumor necrosis factor (TNF-α), as well as redox-markers malondialdehyde (MDA) and nitric oxide (NO), hemoglobin (Hgb), white and red blood cells (WBCs, RBCs), and platelet counts were assessed following irradiation. Of the immune-stimulant category, .25 Gy dose offered EP-comparable effects in TNF-α, RBCs, Hgb, and platelet counts cases. As for the immune-suppressive category; 5 Gy irradiation dose induced inflammatory/immunosuppressive responses indicated (rise in NO, TNF-α, and IL-10), and an oxidative stress status (increase in serum MDA). However, 5 Gy γ-irradiation was not observed, herein, as a single immunosuppressive agent. To conclude, during radiotherapy, immunological impact(s) of the used radiation doses should be optimized and followed-up closely to assess the risk/benefit of their usage.

Immune system modulation by low-dose ionizing radiation-induced adaptive response

OBJECTIVE

Hormesis or low-dose ionizing radiation is known to induce various biological responses, a subcategory of which is the adaptive response, which has been reported to protect against higher radiation doses via multiple mechanisms. This study investigated the role of the cell-mediated immunological component of low-dose ionizing radiation-induced adaptive response.

METHODS

Herein, male albino rats were exposed to whole-body gamma radiation, using a Cs¹³⁷ source with low-dose ionizing radiation doses of 0.25 and 0.5 Gray (Gy); 14 days later, another irradiation session at a dose level of 5 Gy was carried on. Four days post-irradiation at 5 Gy, rats were sacrificed. The low-dose ionizing radiation-induced immuno-radiological response has been assessed through the T-cell receptor (TCR) gene expression quantification. Also, the serum levels of each of interleukins-2 and -10 (IL-2, IL-10), transforming growth factor-beta (TGF-β), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) were quantified.

RESULTS

Results indicated that priming low irradiation doses resulted in significant decrements in TCR gene expression and the serum levels of IL-2, TGF-β, and 8-OHdG with an increment in IL-10 expression compared to the irradiated group, which did not receive low priming doses.

CONCLUSION

The observed low-dose ionizing radiation-induced radio-adaptive response significantly protected against high irradiation dose injuries, through immune suppression, representing a promising pre-clinical protocol that would be applied to minimize radiotherapy side effects on normal but not against the tumor cells.

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.

Pterostilbene Inhibits Dyslipidemia-Induced Activation of Progenitor Adipose Gene Under High-Fat Diet and Radiation Stressor

Repeated exposure to ionizing radiation has been reported to increase the risk of chronic metabolic disorders such as systemic hyperlipidemia and intracellular lipid accumulation that might lead to diabetes-induced heart disease. The purpose of this study was to investigate the effect of pterostilbene on high-fat diet rats suffering from ionizing radiation-induced hyperlipidemia. High-fat diet rats showed an increase in body weight and body fat compared with rats fed with normal chow. Pterostilbene and Orlistat treatments resulted in lower body weight and body fat gain, insulin resistance, reduced lipid peroxidation with attenuated liver enzyme levels, and regulated lipogenesis-related genes in the HFD + IR rat group. Regulation of Peroxisome proliferator-activated receptor-γ (PPAR-γ) mRNA enhanced paraoxonase-1 (PON-1) and arylesterase (AE) activities and inhibited that of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA). It also increased the activities of plasma lecithin-cholesterol acyltransferase (LCAT) and lipoprotein lipase (LPL). Pterostilbene and Orlistat also corrected the alterations of serum leptin and adiponectin levels in lipidemic rats. Such findings provide evidence that Pterostilbene and Orlistat can act as normolipidemic agents that possess lipid-lowering effects and potential as a radioprotector.

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.

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.