Calcitriol Ameliorates Brain Injury in the Rat Model of Cerebral Ischemia-Reperfusion Through Nrf2/HO-1 Signalling Axis: An in Silico and in Vivo Study.

OBJECTIVES: Calcitriol has been revealed to exert neuroprotective effects in ischemic stroke; however, its role and the underlying mechanisms in brain injury induced by ischemia are not well known. The purpose of this study was to determine the neuroprotective effects of calcitriol pretreatment and to assess the possible neuroprotective function of nuclear factor erythroid 2-related factor 2 (Nrf2)/ heme oxygenase-1 (HO-1) signalling pathway against brain ischemia/reperfusion (I/R) injury in the rat models which was followed by a bioinformatics approach. METHODS: The experimental I/R model induction was performed in male Wistar rats for 1 h followed by 23 h reperfusion. Calcitriol was administered intraperitoneally for 7 days prior to stroke. Following ischemia induction 24 h later, neurobehavioral deficits and infarction volume were examined. Oxidative stress was assessed by measurement of malondialdehyde (MDA), nitric oxide (NO) and total antioxidant capacity (TAC). The protein and mRNA expression of HO-1 and Nrf2 were determined by western blot and reverse transcription polymerase chain reaction (RT-PCR), respectively. A molecular docking approach was applied to identify the interaction value of Keap1 with calcitriol. RESULTS: Our data demonstrated that calcitriol significantly decreased infarction volume and ameliorated neurological deficits in brain I/R. MDA and NO levels were decreased and TAC level was elevated significantly after calcitriol pretreatment. Furthermore, calcitriol upregulated the expression of HO-1 and Nrf2 protein and mRNA in ischemic brain. Molecular modelling demonstrated that calcitriol could interact with the pocket of Keap1 by an appropriate binding energy. CONCLUSIONS: The results indicate that calcitriol protects the brain against I/R injury. This effect may pass through inhibition of oxidative stress and Nrf2/HO-1 pathway activation and this may arise by interaction of Keap1 and calcitriol.

Neuroprotective effect of melatonin on radiation-induced oxidative stress and apoptosis in the brainstem of rats.

This study aimed to determine the effects of melatonin on irradiation-induced apoptosis and oxidative stress in the brainstem region of Wistar rats. Therefore, the animals underwent whole-brain X-radiation with a single dose of 25 Gy in the presence or absence of melatonin pretreatment at a concentration of 100 mg/kg BW. The rats were allocated into four groups (10 rats in each group): namely, vehicle control (VC), 100 mg/kg of melatonin alone (MLT), irradiation-only (RAD), and irradiation plus 100 mg/kg of melatonin (RAM). An hour before irradiation, the animals received intraperitoneal (IP) melatonin and then were killed after 6 hr, followed by measurement of nitric oxide (NO), malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), and total antioxidant capacity (TAC) in the brainstem region. Furthermore, the western blot analysis technique was performed to assess the caspase-3 expression level. Results showed significantly higher MDA and NO levels in the brainstem tissues for the RAD group when compared with the VC group (p < .001). Moreover, the irradiated rats exhibited a significant decrease in the levels of CAT, SOD, GPx, and TAC (p < .01, p < .001, p < .001, and p < .001, respectively) in comparison to the VC group. The results of apoptosis assessment revealed that the expression level of caspase-3 significantly rose in the RAD group in comparison with the VC group (p < .001). Pretreatment with melatonin ameliorated the radiation-induced adverse effects by decreasing the MDA and NO levels (p < .001) and increasing the antioxidant enzyme activities (p < .001). Consequently, the caspase-3 protein expression level in the RAM group showed a significant reduction in comparison with the RAD group (p < .001). In conclusion, melatonin approximately showed a capacity for neuroprotective activity in managing irradiation-induced oxidative stress and apoptosis in the brainstem of rats; however, the use of melatonin as a neuroprotective agent in humans requires further study, particularly clinical trials.

Prenatal exposure to diesel exhaust particles causes anxiety, spatial memory disorders with alters expression of hippocampal pro-inflammatory cytokines and NMDA receptor subunits in adult male mice offspring.

Air pollution by Diesel exhaust (DE) consists of gaseous compounds and diesel exhaust particles (DEPs). Previous studies show associations between prenatal exposure to diesel exhaust affects the central nervous system (CNS). However, there was not reported that these effects were caused by gaseous compounds, diesel exhaust particles, or both. A limited number of studies in rodent models have shown that exposure to DEPs can result in CNS. Here, we explored the effects of prenatal exposure to DEPs on anxiety and learning and memory in NMRI mice male offspring. Three groups of pregnant mice were exposed to 350-400 µg DEPs/m3 for 2, 4 and 6 h daily in a closed system room. We examined anxiety and learning and memory in 8-to-9-week-old male offspring using the Elevated plus maze and Morris water maze (MWM) test. Hippocampi were isolated after the behavioral tests and measured pro-inflammatory cytokines and N-methyl-D-aspartate (NMDA) receptor expression by quantitative RT-PCR analysis. Mice exposed to DEPs in utero showed deficits in the Elevated plus maze and Morris water maze test. In addition, DEPs exposed mice exhibited decreased hippocampal NR2A and NR3B expression. Taken together, our data suggest that maternal DEP exposure is associated with anxiety, disrupts learning and memory and reduction hippocampal NR2A and NR3B expression in male offspring.

Exposure to nanoscale diesel exhaust particles: Oxidative stress, neuroinflammation, anxiety and depression on adult male mice.

Exposure to nanoscale diesel engines exhausted particles (DEPs) is a well-recognized risk factor for respiratory and cardiovascular diseases. Rodents as commonly used models for urban air pollution in health effect studies demonstrate constant stimulation of inflammatory responses in the main areas of the brain. Nevertheless, the primary effect of diesel exhaust particulate matter on some of the brain regions and relation by behavioral alterations still remains untouched. We evaluated the brain regional inflammatory responses to a nanosized subfraction of diesel engines exhaust particulate matter (DEPs < 200 nm) in an adult male mice brain. Adult male mice were exposed to DEPs for 3, 6, and 8 h per day, 12 weeks and five days per week. Degree of anxiety and the depression by elevated plus maze and Forced Swimming Test respectively (FST) did measurement. After behavior tests, the plasma and some of the brain regions such as olfactory bulb (OB) and hippocampus (HI) were analyzed for oxidative stress and inflammatory responses. The inflammation and oxidative stress changes in OB and HI, markedly coincides with the results of behavioral alterations. These responses corresponded with rapid induction of MDA and nitrite oxide (NO) in brain regions and neuronal nitric oxide synthase (nNOS) mRNA followed by IL6, IL1α, and TNFα in OB and HI. The different times of DEPs exposure, leads to oxidative stress and inflammatory in plasma and brain regions. That this cumulative transport of inhaled nanoscale DEPs into the brain and creating to inflammation responses of brain regions may cause problems of brain function and anxiety and depression.

Role of Steroid Therapy after Ischemic Stroke by n-Methyl-d-Aspartate Receptor Gene Regulation.

BACKGROUND: Stroke is the main cause of cerebrovascular disease mortality. Prolonged stimulation of n-methyl-d-aspartate (NMDA) receptor subtypes by the accumulation of glutamate neurotransmitter in the extracellular space after a stroke could activate cell death pathways. It is reported that progesterone provides different mechanisms of neuroprotection and could be considered as a candidate for stroke treatment. This study aimed to investigate progesterone impact on the expression of NMDA receptor subunits NR1, NR2 (A and B), NR3 (A and B) after an experimental model of ischemic stroke which is followed by an in silico analysis. METHODS: Progesterone was introduced subcutaneously after transient middle cerebral artery occlusion in male rats. After a period of reperfusion, a set of behavioral tests was performed to evaluate the postischemic neurological deficits. The 2,3,5-triphenyltetrazolium chloride staining method was done for quantification of infarct volume and gene expression analysis was performed in the penumbra region using reverse transcription polymerase chain reaction for NMDA receptor subunits. An AutoDock tool was employed to perform molecular docking analyses for evaluation of progesterone interaction with NMDA receptor. RESULTS: Cerebral ischemia caused a significant downregulation in NR1, NR2A, NR2B and a profound upregulation of NR3B in cortical penumbra region. Treatment with progesterone resulted in upregulation of NR1, NR2A, and NR3B which could explain a possible the neuroprotection of steroids via binding to NMDA glutamate receptor. In addition, in silico analysis revealed that progesterone could strongly interact with NR1/NR2B and NR2A. CONCLUSION: The findings elucidate a new aspect of the neuroprotective mechanism of progesterone via NMDA receptors gene regulation.

G-Protein-Coupled Receptors and Ischemic Stroke: a Focus on Molecular Function and Therapeutic Potential.

In ischemic stroke, there is only one approved drug, tissue plasminogen activator, to be used in clinical conditions for thrombolysis. New neuroprotective therapies for ischemic stroke are desperately needed. Several targets and pathways have been shown to confer neuroprotective effects in ischemic stroke. G-protein-coupled receptors (GPCRs) are one of the most frequently targeted receptors for developing novel therapeutics for central nervous system disorders. GPCRs are a large family of cell surface receptors that response to a wide variety of extracellular stimuli. GPCRs are involved in a wide range of physiological and pathological processes. More than 90% of the identified non-sensory GPCRs are expressed in the brain, where they play important roles in regulating mood, pain, vision, immune responses, cognition, and synaptic transmission. There is also good evidence that GPCRs are implicated in the pathogenesis of stroke. This review narrates the pathophysiological role and possible targeted therapy of GPCRs in ischemic stroke.

Effect of topical Areca palm L. hydroalcoholic extract on burn wound healing in rats.

OBJECTIVES: Wound healing is a complex and dynamic process that begins immediately following tissue injury and continues until the wound is completely healed and remodeled. Applying the most effective burn repair techniques is a constant challenge in medicine. Antiulcerogenic and wound healing properties of Areca palm leaves have been validated through various investigations and animal studies. This study aimed to determine the potential for A. palm hydroalcoholic extract to heal burn wounds in rats. MATERIALS AND METHODS: For 14 days, we examined 40 male Wistar albino rats in 5 groups: those receiving 1% silver sulfadiazine cream (reference standard), those receiving eucerin (positive control), and those receiving 5% and 10% ointments of Areca catechu hydroalcoholic extract (treatment groups). No treatment was given to the negative control group. On the dorsal part of the animals' necks, burn wounds were made. After the rats were sacrificed, the wound contraction rate (WCR) was determined, and the wound sites were histopathologically examined. RESULTS: On the 14th day, the WCR was significantly higher in rats treated with A. palm 10% extract ointment than in rats treated with 5% extract, positive or negative control groups (p < 0.001), or rats treated with silver sulphfadiazine (p = 0.01). After applying a 10% extract ointment to burn wound sites, complete healing occurred with only mild tissue inflammation and edema. CONCLUSION: The study's findings indicate that the hydroalcoholic extract of A. palm L. has the ability to expedite the wound healing process. Additional research is necessary to identify the compounds responsible for their wound healing properties and comprehend their action mechanism.

Protective effects of Echium amoenum Fisch. and C.A. Mey. against cerebral ischemia in the rats.

BACKGROUND: This study was designed to evaluate the protective effect of Echium amoenum total anthocyanin extract (ETAE) on partial/transient cerebral ischemia in the rats. MATERIALS AND METHODS: Rats received ETAE (50, 100 and 200 mg/kg, i.p.) 30 min before the induction of cerebral ischemia. Cerebral ischemia was induced by bilateral common carotid arteries occlusion (BCCAO) for 30 min, followed by 72 h reperfusion. The neurological deficit, brain performance, and sensory motor function were assessed 48 h and 72 h after surgery. After sacrification, the brains were evaluated for myeloperoxidase (MPO) activity and histopathological changes. RESULTS: Our results showed that motor function significantly decreased in ischemia/reperfusion (I/R) group as compared to the sham group. Histopathological analysis exhibited the shrinkage and atrophy of the neurons in I/R group. ETAE at the dose of 200 mg/kg improved spontaneous activity and memory induced by cerebral ischemia compared to the control group and also decreased brain MPO activity following cerebral ischemia. However, it could not affect the ability to climbing, body proprioception, vibrissae touch and brain water content. In addition, pretreatment with ETAE at higher doses significantly reduced ischemia-induced neuronal loss of the brain. CONCLUSION: The anthocyanin rich fraction from E. amoenum was found to have protective effects against some brain damages postischemic reperfusion. However, further researches are required for investigating the exact mechanisms of the effect of this plant in the prevention of cerebral ischemia in human.

Internalization and signal transduction of PrP(106-126) in neuronal cells.

Invasion of the nervous system and neuronal spread of infection are critical, but poorly understood steps in the pathogenesis of prion diseases. We have thus analyzed the internalization and signal transduction of the neurotoxic fragment of the prion protein PrP(106-126) in the rat neuroblastoma cell line B104 by fluorescence microscopy and quantification by ELISA and in primary neuronal cells from mice. Phospholipase D (PLD) is known to be an enzyme involved in the regulation of secretion, endocytosis and receptor signalling. We determined the PLD activity using a transphosphatidylation assay and could show that PLD is involved in PrP(106-126) internalization. The determination of receptor activity via quantification of ERK1/2 phosphorylation and cAMP level measurement verified the PrP(106-126)-induced signal transduction in B104 cells and primary neuronal cells. PrP(106-126)-induced a decrease in cAMP level in neuronal cells. These studies indicate the involvement of PLD in PrP(106-126)-endocytosis and mediated cellular signalling by an unidentified inhibitory G-protein-coupled receptor and may allow the development of therapeutic agents interfering with prion uptake and/or PLD function using PLD as a possible pharmaceutical target.