Effect of lidocaine on oxidative activity of peripheral blood phagocytes

BACKGROUND: Excessive production of reactive oxygen species (ROS) by leukocytes can cause damage to intrinsic tissues. The pathogenesis of sepsis is based on an excessive inflammatory response of the body. Several studies have reported the inhibitory effect of lidocaine on neutrophilic granulocytes. AIM: This study aimed to analyze the effect of lidocaine on the oxidative activity of phagocytes. MATERIALS AND METHODS: Blood from 16 healthy donors was used in this study. Leukocyte mass was extracted using spontaneous sedimentation. Half of the leukocyte samples were incubated in buffered physiological saline with lidocaine. The other half of the leukocyte samples were incubated in physiological saline without lidocaine. The generation of ROS was studied using two methods. Method 1 included a nitro blue tetrazolium (NBT) test), which is based on the ability of ROS to reduce NBT to insoluble diformazan. Method 2 was based on the chemiluminescence reaction. A culture of S. Aureus was used to induce the production of ROS. RESULTS: NBT test revealed a decrease in the oxidative activity of leukocytes in the presence of lidocaine by 18% (p 0.05). The study of luminol-dependent chemiluminescence of leukocyte suspension in the presence of lidocaine revealed a significant 2-fold decrease in both spontaneous and stimulated respiratory activity of cells. CONCLUSIONS: After incubation with lidocaine, phagocytes generated ROS to a significantly lower extent. However, their complete blockade was not recorded. This property of lidocaine may be used in clinical practice to treat an excessive inflammatory response in sepsis.

Evaluation of a natural compound extracted from Dolichandrone atrovirens as a novel antioxidant agent using Caenorhabditis elegans

The compound methyl cinnamoyl catalpol (DAM-1) was isolated from the methanol extract of Dolichandrone atrovirens. Studies have already reported the antioxidant activity of Dolichandrone atrovirens bark extract, but till date the antioxidant activity of the isolated compound DAM-1, remains unexplored. The endogenous process of reactive oxygen species generation which leads to various degenerative diseases, can be broken down using these exogenous moieties from plant origin, herein this study we sought to evaluate the antioxidant potential of the DAM-1 compound using Caenorhabditis elegans (C. elegans), which is the primary model to study the antioxidant activity of compounds. Cytotoxicity assay results showed that DAM-1 treatment in the concentration of 10, 25 and 50 μg/ml has shown 100%, 91%, and 50% survival respectively with overall p<0.0001 (treatment v/s control group). 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide–Formazan (MTT) assay results showed that treatment had better survival rates than the control group at different time intervals i.e. 48 h, and 72 h with p<0.01. Mechanosensation (behavioral study) as well as in vivo study results showed that at 0 h, 10 μg/ml of DAM-1 treatment showed a better anti-oxidative activity than the control group, 25 and 50 μg/ml of DAM-1 treated groups with p<0.001 but at 2.5 h incubation with 10, 25, 50 μg/ml of DAM-1 showed an increased anti-oxidative activity than the control group with p<0.001. Thermoresistance assay confirmed that the treatment group had more survival than control group with p<0.001. Absorption study of DAM-1 in C. elegans has shown that the absorption of the drug increases up to 180 mins with a slight decrease after 360 mins and then constant absorption up to 1440 mins. This study paves the way towards the initiative to explore the pharmacological role of DAM-1 in various oxidative stress mediated diseases at molecular levels and the absorption study points out its potential role which could be utilized in the metabolomics and proteomics analysis of this compound in other studies.

Study of the effects of Silicea terra and Zincum metallicum in various dilutions on the oxidative activity of macrophages in vitro

Silica (silicon dioxide) is found in nature, being composed of 2 chemical elements abundant on the Earth's crust, oxygen and silicon. As homeopathic medicine, silica is used for treatment of chronic ulcers due to its ability to modulate the macrophage activity. Zinc is a cofactor of several immune mediators, especially thymulin, which is also capable of modulating the macrophage activity and recruitment of B1 cells in mice. In the present study, we assessed the homeopathic medicines Silicea terra and Zincum in an in vitro experimental model to determine their effects on the interaction between RAW 264.7 macrophages and BCG (Bacillus Calmette-Guérin). In this step of the study, we assessed oxidative activity through measurement of hydrogen peroxide and nitrite/nitrate in the cell culture supernatant after 24 hours of treatment. Several homeopathic potencies were used for both drugs (6cH, 30cH, 200cH). The tests were performed in duplicate, and the data were analyzed by means one-way ANOVA. The results show no effect on nitric oxide (NO) production, but reduction of hydrogen peroxide production (p≤ 0.001) after treatment with the vehicle (0.03% alcohol). Such reduction was reversed with treatments Silicea terra30cH and Zincum metallicum 30cH (p≤ 0.001). Treatment with Silicea terra 200cH induced significant reduction of hydrogen peroxide production, even when compared to the vehicle (p≤ 0.005). Taken together, the results indicate that only treatment of BCG-challenged macrophages with Silicea terra 200cH was able to significantly reduce the oxidative activity of these cells after 24 hours of incubation. Since NO production in vitro usually occurs after 96 to 120 hours of incubation, one might infer that the negative result obtained in the present study might be associated with the time-point of assessment. Other aspects of the macrophage-BCG interaction are still under evaluation.

Melatonin Successfully Rescues the Hippocampal Molecular Machinery and Enhances Anti-oxidative Activity Following Early-Life Sleep Deprivation Injury

Early-life sleep deprivation (ESD) is a serious condition with severe cognitive sequelae. Considering hippocampus plays an essential role in cognitive regulation, the present study aims to determine whether melatonin, a neuroendocrine beard with significant anti-oxidative activity, would greatly depress the hippocampal oxidative stress, improves the molecular machinery, and consequently exerts the neuro-protective effects following ESD. Male weanling Wistar rats (postnatal day 21) were subjected to ESD for three weeks. During this period, the animals were administered normal saline or melatonin (10 mg/kg) via intraperitoneal injection between 09:00 and 09:30 daily. After three cycles of ESD, the animals were kept under normal sleep/wake cycle until they reached adulthood and were sacrificed. The results indicated that ESD causes long-term effects, such as impairment of ionic distribution, interruption of the expressions of neurotransmitters and receptors, decreases in the levels of several antioxidant enzymes, and impairment of several signaling pathways, which contribute to neuronal death in hippocampal regions. Melatonin administration during ESD prevented these effects. Quantitative evaluation of cells also revealed a higher number of neurons in the melatonin-treated animals when compared with the saline-treated animals. As the hippocampus is critical to cognitive activity, preserving or even improving the hippocampal molecular machinery by melatonin during ESD not only helps us to better understand the underlying mechanisms of ESD-induced neuronal dysfunction, but also the therapeutic use of melatonin to counteract ESD-induced neuronal deficiency.