Impact of Different Oxygen Supply Methods on the Healing of Corneal Epithelial Wound and the Level of Acetylcholine

Purpose. To investigate the impact of different oxygen supply methods on corneal epithelial wound healing and acetylcholine level during wound healing. Methods. We randomly divided 75 rabbits into three groups: A, B, and C, with 25 rabbits in each group. The central corneal epithelium was removed from all eyes of the rabbits using a 5 mm trephine. Group A rabbits were given low flow oxygen (3 L/min; concentration: 33%) for 2 h per day through goggles. Group B rabbits were given low flow oxygen (3 L/min; concentration: 33%) for 2 h per day via oxygen masks for inhalation. Group C rabbits healed naturally. The area of healed corneal epithelium and acetylcholine content in corneal epithelium were determined at 12 h, 24 h, and 36 h after injury. Results. At 12 h, 24 h, and 36 h after injury, the healing area of corneal epithelium in the three groups was in the order group A > group B > group C ( P < 0.05 ). At all timepoints, the acetylcholine level in corneal epithelium was in the order of group A > group B > group C ( P < 0.05 ). In all three groups, the acetylcholine content in corneal epithelium showed the order 12 h > 24 h > 36 h ( P < 0.05 ). There was a correlation between acetylcholine expression and the area of unhealed corneal epithelium, and the correlation coefficients of groups A, B, and C were 0.80, 0.83, and 0.85 respectively. Conclusion. Increasing oxygen concentration through inhalation or via goggles can promote corneal epithelial wound healing, but increasing local oxygen concentration of the eye showed a better effect. Acetylcholine may play an important role in the early process of corneal epithelial wound healing.

Exercise prevents HFD-induced insulin resistance risk: involvement of TNF-α level regulated by vagus nerve-related anti-inflammatory pathway in the spleen

Objectives Regular physical exercise can improve insulin resistance in insulin target tissues. However, the mechanisms about the beneficial effect of exercise on insulin resistance are not yet fully resolved. This study was carried out to address whether insulin resistance improvement by exercise is involved in an anti-inflammatory pathway in the spleen in high-fat diet (HFD) feeding mice. Methods Male C57Bl/6J mice with or without subdiaphragmatic vagotomy (sVNS) were subjected to medium-intensity treadmill exercise during HFD feeding. Glucose tolerance test and insulin tolerance test were detected, and spleen acetylcholine level, choline acetyltransferase activity (ChAT), protein kinase C (PKC) and tumor necrosis factor-alpha (TNF-α) were assayed. Results We found that exercise significantly improves HFD-induced glucose intolerance and insulin resistance, along with an increase in acetylcholine level, ChAT activity, and PKC activity, and decrease in TNF-α level in the system and the spleen from HFD-fed mice. However, sVNS abolished the beneficial effect of exercise on glucose intolerance and insulin resistance, decreased acetylcholine level, ChAT activity, and PKC activity, and increase TNF-α level of the spleen in HFD-mice exercise intervention. Conclusions These data reveal that the prevention of HFD-associated insulin resistance by exercise intervention involves reducing splenic TNF-α level, which is mediated by cholinergic anti-inflammatory activity via influencing PKC activity, ChAT activity, and acetylcholine concentration in mice spleen.

D-serine supplement ameliorates MPP+-induced neurotoxicity via attenuating DAPK1-associated pathway in Parkinson's disease models

Background: D-serine is reported to modulate neurotransmission via regulating the activation of N-methyl-D-aspartate receptor 1 (NMDAR1) in a narrow range, and dysfunction or dysregulation of NMDAR1 contributes to the pathophysiology of Parkinson's disease (PD), a chronic and progressive neurodegenerative disorder. This study aims to further elucidate the action mechanism of D-serine/NMDAR1 in PD. Methods and Results: At animal level, we found D-Serine and NMDAR1 were cooperatively distributed in mouse brains. Compared to the control mice, a dramatic increase in D-serine content and NMDAR1 expression was revealed in striatum, whereas a significant reduction was found in cortex, hippocampus, cerebellum and brainstem in PD mice. Thus, the tissue-specific D-serine/NMDAR1 was suspected to be associated with PD. Based on the decreased levels of NMDAR1 and D-serine in the MPP+-treated glioma cells, a D-serine supplement was introduced. We found that D-serine supplement enhanced NMDAR1 expression, and triggered neuronal cells to be rescued supporting by parkinsonian parameters including morphological observation, a decreased ROS level, an increased dopamine content, and a declined acetylcholine level. Additionally, a decreased calcium, reduced DAPK1 expression, and raised Bcl2 level were found in neuronal cells supplied with D-serine. Conclusions: We speculated that D-Serine attenuated neuronal cell death via inhibiting DAPK1-related pathway. Additionally, D-serine was confirmed to display an ability to ameliorate the MPTP injury using the MPTP-administrated mice injected with D-serine. Unlike the previous description, D-serine displays a protective effect on neuronal cells. Overall, our finding highlights D-serine as a strong enhancer for NMDAR1 expression and a candidate for PD therapy. This opens up an innovative perspective for neurobiological therapy using D-serine augmentation.

Exploration of Potent Multi-Target-Directed-Ligands as Anti-Alzheimer’s Disease Agents: A Moiety Based Review

: Dementia is a chronic neurodegenerative disease and maximum of the cases are directly related to Alzheimer’s disease. More than 4 million people are living with Alzheimer’s disease related dementia in India, making it a global crisis. Alzheimer’s disease deteriorates cognitive functions with the passage of time and consists of multifaceted factors such as decline of acetylcholine level, amyloid β-aggregation, tau hyperphosphorylation, oxidative stress, etc. The classical drugs used till date, are focused on only one target and not serving the cause properly. Hence, the community of scientists are rigorously working on multi-target-directed agents that incorporate two or more active scaffolds in one compound or hybrid of active moieties. This article aims at the evaluation of novel potential compounds and moieties such as quinolines, chalcones, coumarins, chromenes, piperazine, carbazoles, cinnamic acids, tacrine hybrids, donepezil hybrids and so on that have been introduced as multi-target-directed agents in recent five years.

Synthesis, Antioxidant, Anticholinesterase Activities and Molecular Docking Studies of coumaryl 1,3-selenazoles Derivatives

Inhibition of acetylcholinesterase (AChE) enzyme is a known procedure to treat severe Alzheimer's disease through increasing the acetylcholine level in the brain and thus slowing down the progression of Alzheimer's symptoms. The approved medications are only considered as palliative and addressed some reported deficiencies. Therefore, the demand for safe and effective compounds is substantially increasing. A newly series of coumaryl 1,3-selenazoles derivatives was synthesized in four steps. Then, their antioxidant activities were evaluated using DPPH, ABTS cation radical scavenging assay and cupric reducing antioxidant capacities (CUPRAC). The anticholinesterase activities were evaluated using the Ellman method. Then, the docking studies were carried out to explain the possible correlation between in vitro anticholinesterase activity results and the ligand-receptor interactions. Ten new coumaryl 1,3-selenazoles (5a-5d series and 6a-6f series) derivatives were successfully synthesized. The DPPH radical scavenging assay showed that all tested compounds have IC50 value &amp;gt; 200 &mu;M, for ABTS cation radical scavenging assay the IC50 value &amp;gt; 1000 &mu;M and for CUPRAC assay the IC50 value &amp;gt; 200 &mu;M. Compound 5c was found to be the most active compound against AChE and BChE in its series with IC50 value for AChE is 99.76 &mu;M and IC50 for BChE is 140.28 &mu;M while 6b exhibited the most potent inhibition in its series with IC50 value for AChE is 56.01 &mu;M and IC50 for BChE is 121.34 &mu;M. Besides, the docking studies showed that compound 5c and 6b formed &pi;-&pi; stacking interaction with aromatic residues at the active site of AChE and BChE, which is responsible for inhibiting the enzymes. This shows that the synthesized compounds contain skeletal structures that can interact and inhibit within the enzymes active site.

Behavioral and Biochemical Effects of Mukia madrespatana Following Single Immobilization Stress on Rats

Background and Objectives: Elevated oxidative stress has been shown to play an important role in the diagnosis and prognosis of stress and memory-related complications. Mukia madrespatana (M. madrespatana) has been reported to have various biological and antioxidant properties. We intended to evaluate the effect of M. madrespatana peel on single immobilization stress-induced behavioral deficits and memory changes in rats. Materials and Methods: M. madrespatana peel (2000 mg/kg/day, orally) was administered to control and immobilize stressed animals for 4 weeks. Anxiolytic, antidepressant, and memory-enhancing effects of M. madrespatana were observed in both unstressed and stressed animals. Results: Lipid peroxidation was decreased while antioxidant enzymes were increased in both unstressed and stressed animals. Acetylcholine level was increased while acetylcholinesterase activity was decreased in both M. madrespatana treated unstressed and stressed rats. There was also an improvement in memory function. Serotonin neurotransmission was also regulated in M. madrespatana treated rats following immobilization stress with anxiolytic and anti-depressive effects. Conclusion: Based on the current study, it is suggested that M. madrespatana has strong antioxidant properties and may be beneficial as dietary supplementation in stress and memory-related conditions.

Zn-Doped TiO2 Powder Prepared by Solution Combustion Synthesis as Non-Enzymatic Sensor for Acetylcholine Detection

Acetylcholine (ACh) is a main neurotransmitter functioning in smooth muscle and cardiovascular system control. It also plays a key role in memory and learning. While excessive acetylcholine level results in decreased heart rates, depleted level of acetylcholine in human brains can lead to Alzheimer disease. Therefore, detection of acetylcholine is clinically vital. This study aimed at examining potential usage of titanium dioxide (TiO2) doped with 2.5 mol% Zn as electrochemical sensors for acetylcholine detection. Zn-doped TiO2 powder was synthesized by a solution combustion technique. Phase identification, microstructural examination, as well as electrocatalytic activity evaluation of the synthesized powder were conducted. The synthesized powder showed anatase phase with fine particle sizes ranging from 9.3 to 11.4 nanometers on average. Specific surface area of 75.48 m2/g was observed. Electrocatalytic activities of the powder in cholin acetate solutions with concentrations ranging from 0.05 to 0.1 μM and 1 to 10 μM were evaluated via cyclic voltammetry technique. At applied voltage of 0.05 V, peak currents corresponding to oxidation reactions between ACh and Zn-doped TiO2 were detected. Sensitivity values of 3.13x10-4 and 1.32 μA/(μMmm2), which is in an acceptable range, were evident.

Association between ECG Alterations and Outcomes of Patients with Acute Organophosphate Poisoning

Background: Organophosphate (OP) poisoning leads to atrioventricular node blockade, alterations in ST segment, prolongation of QT interval, alterations in P wave, lethal arrhythmias, and cardiac arrest through the inhibition of acetylcholinesterase and consequent accumulation of free synaptic acetylcholine level. So the present study was aimed to investigate the role of electrocardiographic (ECG) monitoring combined with the introduction of anti-arrhythmic interventions on OPs poisoning outcomes. Methods: 41 patients with OPs poisoning were included. Patients with history of heart or liver diseases, cholinesterase deficiency, anemia, and poisoning with other toxins were excluded. Demographic characteristics, the time elapsed between OP ingestion and hospital admission, need for mechanical ventilation, and serum cholinesterase level were recorded. ECG of patients was analyzed for rate, rhythm, ST-T abnormalities, conduction defects, and measurement of PR and QT intervals. Study outcomes were measures of morbidity and mortality. Results: Of 41 patients, with mean age of 34.76±13 years, 19 were male. For 68.3% of the patients, the time elapsed between ingestion and hospital admission was 3-6 hours. Eight patients were treated with mechanical ventilation. There was a significant correlation between ST segment alterations and poisoning outcomes including uncomplicated discharge, complicated discharge, and death (P=0.02). Thirty one patients were discharged without any complication, 8 with morbidity and 2 expired. ST segment changes were seen in 4 patients. Two percent had PR interval greater than 0.21s and 3% had QT interval longer than 0.45s. The mean serum cholinesterase concentration was 3011.56 U/L. Conclusion: Due to lethal cardiac arrhythmia caused by OP poisoning, continuous monitoring, managing, and preventing irreparable effects of OP poisoning is highly emphasized.