Effects of non-steroidal antiinflammatory drugs on D-serine-induced oxidative stressin vitro

Design, Synthesis, and Biological Evaluation of Novel Tomentosin Derivatives in NMDA-Induced Excitotoxicity

N-methyl-D-aspartate (NMDA) receptor stimulation may lead to excitotoxicity, which triggers neuronal death in brain disorders. In addition to current clinical therapeutic approaches, treatment strategies by phytochemicals or their derivatives are under investigation for neurodegenerative diseases. In the present study, novel amino and 1,2,3-triazole derivatives of tomentosin were prepared and tested for their protective and anti-apoptotic effects in NMDA-induced excitotoxicity. Amino-tomentosin derivatives were generated through a diastereoselective conjugate addition of several secondary amines to the α-methylene-γ-butyrolactone function, while the 1,2,3-triazolo-tomentosin was prepared by a regioselective Michael-type addition carried out in the presence of trimethylsilyl azide (TMSN3) and the α-methylene-γ-lactone function. The intermediate key thus obtained underwent 1,3-dipolar Huisgen cycloaddition using a wide range of terminal alkynes. The possible effects of the derivatives on cell viability and free-radical production following NMDA treatment were measured by Water-Soluble Tetrazolium Salts (WST-1) and Dichlorofluorescein Diacetate (DCF-DA) assays, respectively. The alterations in apoptosis-related proteins were examined by Western blot technique. Our study provides evidence that synthesized triazolo- and amino-tomentosin derivatives show neuroprotective effects by increasing cellular viability, decreasing ROS production, and increasing the Bcl-2/Bax ratio in NMDA-induced excitotoxicity. The findings highlight particularly 2e, 2g, and 6d as potential regulators and neuroprotective agents in NMDA overactivation.

Naproxen as a potential candidate for promoting rivastigmine anti-Alzheimer activity against aluminum chloride-prompted Alzheimer's-like disease in rats; neurogenesis and apoptosis modulation as a possible underlying mechanism

BACKGROUND AND AIM

Alzheimer's disease (AD) is one of the leading causes of dependence and disability among the elderly worldwide. The traditional anti-Alzheimer medication, rivastigmine, one of the cholinesterase inhibitors (ChEIs), fails to achieve a definitive cure. We tested the hypothesis that naproxen administration to the rivastigmine-treated aluminum chloride (AlCl3) Alzheimer's rat model could provide an additive neuroprotective effect compared to rivastigmine alone.

MATERIALS AND METHODS

The studied groups were control (Cont), AlCl3 treated (Al), rivastigmine treated (RIVA), naproxen treated (Napro), and combined rivastigmine and naproxen treated (RIVA + Napro). Rats' memory, spatial learning, and cognitive behavior were assessed followed by evaluation of hippocampal acetylcholinesterase (AChE) activity. Hippocampal and cerebellar histopathology were thoroughly examined. Activated caspase-3 and the neuroepithelial stem cells marker; nestin expressions were immunohistochemically assayed.

RESULTS

AD rats displayed significantly impaired memory and cognitive function, augmented hippocampal AChE activity; massive neurodegeneration associated with enhanced astrogliosis, apoptosis, and impaired neurogenesis. Except for the enhancement of neurogenesis and suppression of apoptosis, the combination therapy had no additional neuroprotective benefit over rivastigmine-only therapy.

CONCLUSION

Naproxen's efficacy was established by its ability to function at the cellular level, improved neurogenesis, and decreased, apoptosis without having an additional mitigating impact on cognitive impairment in rivastigmine-treated AD rats.

Putative Inflammatory Sensitive Mechanisms Underlying Risk or Resilience to Social Stress

It has been well recognized that exposure to stress can lead to the onset of psychosocial disorders such as depression. While there are a number of antidepressant therapies currently available and despite producing immediate neurochemical alterations, they require weeks of continuous use in order to exhibit antidepressant efficacy. Moreover, up to 30% of patients do not respond to typical antidepressants, suggesting that our understanding of the pathophysiology underlying stress-induced depression is still limited. In recent years inflammation has become a major focus in the study of depression as several clinical and preclinical studies have demonstrated that peripheral and central inflammatory mediators, including interleukin (IL)-1β, are elevated in depressed patients. Moreover, it has been suggested that inflammation and particularly neuroinflammation may be a direct and immediate link in the emergence of stress-induced depression due to the broad neural and glial effects that are elicited by proinflammatory cytokines. Importantly, individual differences in inflammatory reactivity may further explain why certain individuals exhibit differing susceptibility to the consequences of stress. In this review article, we discuss sources of individual differences such as age, sex and coping mechanisms that are likely sources of distinct changes in stress-induced neuroimmune factors and highlight putative sources of exaggerated neuroinflammation in susceptible individuals. Furthermore, we review the current literature of specific neural and glial mechanisms that are regulated by stress and inflammation including mitochondrial function, oxidative stress and mechanisms of glutamate excitotoxicity. Taken together, the impetus for this review is to move towards a better understanding of mechanisms regulated by inflammatory cytokines and chemokines that are capable of contributing to the emergence of depressive-like behaviors in susceptible individuals.

Radioprotective effect of mefenamic acid against radiation-induced genotoxicity in human lymphocytes

Purpose

Mefenamic acid (MEF) as a non-steroidal anti-inflammatory drug is used as a medication for relieving of pain and inflammation. Radiation-induced inflammation process is involved in DNA damage and cell death. In this study, the radioprotective effect of MEF was investigated against genotoxicity induced by ionizing radiation in human blood lymphocytes.

Materials and Methods

Peripheral blood samples were collected from human volunteers and incubated with MEF at different concentrations (5, 10, 50, or 100 µM) for two hours. The whole blood was exposed to ionizing radiation at a dose 1.5 Gy. Lymphocytes were cultured with mitogenic stimulation to determine the micronuclei in cytokinesis blocked binucleated lymphocyte.

Results

A significant decreasing in the frequency of micronuclei was observed in human lymphocytes irradiated with MEF as compared to irradiated lymphocytes without MEF. The maximum decreasing in frequency of micronuclei was observed at 100 µM of MEF (38% decrease), providing maximal protection against ionizing radiation.

Conclusion

The radioprotective effect of MEF is probably related to anti-inflammatory property of MEF on human lymphocytes.

Overdose of D-serine Induces Movement Disorder and Neuromuscular Changes of Zebrafish Larvae

D-serine is a well-known activator of N-methyl-D-aspartate receptors; however, little is known about the teratogenic effects of D-serine overdose during early embryonic development. Here, we used zebrafish as a model to test toxicity and teratogenicity, since they have transparent eggs, making the organogenesis of zebrafish embryos easier to be observed. After D-serine injection (100–1000 ppm), the most evident defective phenotypes were bent trunk phenotypes, including malformed somite boundary, twisted body axis and shorter body length. As the injection dosages increased, the rates of embryos with bent trunk phenotypes decreased (0% for 0 ppm, n=573; 59.9~84.3% for 100–1000 ppm of D-serine, n=383–451). In addition, D-serine-injected embryos exhibited significantly reduced the frequencies of spontaneous in-chorion contraction (21.7 for 0 ppm vs. 18.3–0.9 for 100–1000 ppm D-serine, n=30) in comparison with mock-treated controls (0 ppm). Subtle changes are easily observed by staining with specific monoclonal antibodies F59, Znp1, Zn5 and α-bungarotoxin to detect morphological changes in muscle fibers, primary motor axons, secondary motor axon projections and neuromuscular junctions, respectively. Our data show that overdose of D-serine leads to misalignment of muscle fibers and motor neuron defects, especially secondary motor neuron axonal growth defects.