Cuscuta epithymum Murr. crude extract pre-conditioning protects C6 cells from L-glutamate-induced neurotoxicity.

BACKGROUND: Cuscuta epithymum Murr. (C. epithymum), as an herbal medicine, has played an anti-cancerous role in various studies; however, its possible neuroprotective effects have been neglected. Here, we aimed to investigate the protective effects of C. epithymum seeds crude extract and different fractions on rat glioblastoma cells (C6) in L-glutamate oxidative condition. METHODS: Initially, the total phenolic content of C. epithymum crude extract and the fractions (all produced by maceration method) was determined. Subsequently, C6 cells were pre-treated with the various concentrations of crude extract and fractions 24 h before L-glutamate exposure. Likewise, C6 cells were treated with the same concentrations of crude extract and fractions 24 h after exposure to L-glutamate. The cell viability and morphology were compared in crude extract and fractions groups, then superoxide dismutase (SODs) activity, reactive oxygen species (ROS), and malondialdehyde (MDA) levels were measured. The flow cytometry test was used to study C. epithymum crude extract's effects on the cell cycle and also to quantify the apoptosis, necrosis, and live cells population in different groups. RESULTS: C. epithymum crude extract and fractions (hexanoic, dichloromethanolic, and methanolic) had concentration-dependent cytotoxicity (IC50:126.47, 2101.96, 140.97, and 218.96 µg/ml, respectively). The crude extract and methanolic fraction contained phenolic compounds (55.99 ± 2.795 and 50.80 ± 2.969 mg gallic acid/g extract), while in hexanoic and dichloromethanolic fractions, the phenolic content was undetectable. In the cell viability assay, in comparison to fractions, the crude extract showed a more protective effect against glutamate-induced oxidative condition (P < 0.0001). The crude extract increased the SODs activity (P < 0.001) and decreased MDA and ROS levels (P < 0.0001) in comparison to the glutamate group. The crude extract significantly increased the population of cells in G1 (from 63.04 to 76.29) and decreased the percentage of cells in G2 (from 11.56 to 6.7) and S phase (from 25.4 to 17.01). In addition, it decreased the apoptotic and necrotic cell populations (from 34 to 17.1) and also increased the percentage of live cells (from 66.8 to 83.4 percent) in the flow cytometry test. CONCLUSION: C. epithymum crude extract plays a neuroprotective role by activating the defense mechanisms in cell against the oxidative condition.

The Effect of 40-Hz White LED Therapy on Structure-Function of Brain Mitochondrial ATP-Sensitive Ca-Activated Large-Conductance Potassium Channel in Amyloid Beta Toxicity.

Photobiomodulation therapy has become the focus of medical research in many areas such as Alzheimer's disease (AD), because of its modulatory effect on cellular processes through light energy absorption via photoreceptors/chromophores located in the mitochondria. However, there are still many questions around the underlying mechanisms. This study was carried out to unravel whether the function-structure of ATP-sensitive mitoBKCa channels, as crucial components for maintenance of mitochondrial homeostasis, can be altered subsequent to light therapy in AD. Induction of Aß neurotoxicity in male Wistar rats was done by intracerebroventricular injection of Aß1-42. After a week, light-treated rats were exposed to 40-Hz white light LEDs, 15 min for 7 days. Electrophysiological properties of mitoBKCa channel were investigated using a channel incorporated into the bilayer lipid membrane, and mitoBKCa-ß2 subunit expression was determined using western blot analysis in Aß-induced toxicity and light-treated rats. Our results describe that conductance and open probability (Po) of mitoBKCa channel decreased significantly and was accompanied by a Po curve rightward shift in mitochondrial preparation in Aß-induced toxicity rats. We also showed a significant reduction in expression of mitoBKCa-ß2 subunit, which is partly responsible for a leftward shift in BKCa Po curve in low calcium status. Interestingly, we provided evidence of a significant improvement in channel conductance and Po after light therapy. We also found that light therapy improved mitoBKCa-ß2 subunit expression, increasing it close to saline group. The current study explains a light therapy improvement in brain mitoBKCa channel function in the Aß-induced neurotoxicity rat model, an effect that can be linked to increased expression of ß2 subunit.

Agmatine protects against intracerebroventricular streptozotocin-induced water maze memory deficit, hippocampal apoptosis and Akt/GSK3ß signaling disruption.

Centrally administered streptozotocin (STZ), is known to cause Alzheimer׳s like memory deterioration. It mainly affects insulin signaling pathways such as PI3/Akt and GSK-3ß which are involved in cell survival. Previous studies indicate that STZ increases the ratio of Bax/Bcl-2 and thereby induces caspase-3 activation and apoptosis. Agmatine, a polyamine derived from l-arginine decarboxylation, is recently shown to exert some neuroprotective effects. This study aimed to assess if agmatine reverses STZ-induced memory deficits, hippocampal Akt/GSK-3ß signaling disruption and caspase-3 activation. Adult male Sprague-Dawely rats weighing 200-250 g were used. The canules were implanted bilaterally into lateral ventricles. STZ was administered on days 1 and 3 (3 mg/kg) and agmatine treatment (40 or 80 mg/kg) was started from day 4 and continued in an every other day manner till day 14. The animal׳s learning and memory capability was assessed on days 15-18 using Morris water maze. After complement of behavioral studies the hippocampi was isolated and the amounts of hippocampal cleaved caspase-3 (the landmark of apoptosis), Bax/Bcl-2 ratio, total and phosphorylated forms of GSK-3ß and Akt were analyzed by western blot. The results showed that agmatine in 80 but not 40 mg/kg reversed the memory deterioration induced by STZ. Western blot analysis revealed that STZ prompted elevation of caspase-3; Bax/Bcl-2 ratio and disrupted Akt/GSK-3ß signaling in the hippocampus. Agmatine treatment prevented apoptosis and Akt/GSK-3ß signaling impairment induced by STZ. This study disclosed that agmatine treatment averts not only STZ-induced memory deterioration but also hippocampal apoptosis and Akt/GSK-3ß signaling disruption.