Related Experiment Video

Updated: Jan 25, 2026

Sub-acute Cerebral Microhemorrhages Induced by Lipopolysaccharide Injection in Rats
06:39

Sub-acute Cerebral Microhemorrhages Induced by Lipopolysaccharide Injection in Rats

Published on: October 17, 2018

6.9K

Melatonin attenuates expression of cyclooxygenase-2 (COX-2) in activated microglia induced by lipopolysaccharide

Chunyan Yao1, Xiaoling Liu1, Zhengyu Zhou1

  • 1a Department of Epidemiology , College of Preventive Medicine, Army Medical University (Third Military Medical University) , Chongqing , China.

Journal of Toxicology and Environmental Health. Part A
|May 14, 2019
PubMed

Insights

Melatonin (MEL) reduces neuroinflammation by inhibiting lipopolysaccharide (LPS)-induced cyclooxygenase-2 (COX-2) in microglia. This occurs by blocking key signaling pathways like MAPK and NF-κB, offering potential therapeutic benefits.

Area of Science:

  • Neuroscience
  • Immunology
  • Pharmacology

Background:

  • Lipopolysaccharide (LPS) is a potent neurotoxin that activates microglia, leading to inflammatory neurodegeneration.
  • Melatonin (MEL), a pineal gland hormone, has diverse physiological roles, but its effects on microglia activation are not fully understood.

Purpose of the Study:

  • To investigate the molecular mechanisms by which MEL influences microglia activation, specifically its effect on cyclooxygenase-2 (COX-2) expression in LPS-induced microglia.

Main Methods:

  • Quantitative RT-PCR and Western blot analysis were used to assess COX-2 expression.
  • Enzyme-linked immunosorbent assay (ELISA) measured prostaglandin E2 (PGE2) levels.
  • Analysis of upstream signaling pathways including ERK1/2, JNK, p38 MAPK, and NF-κB activation.

Main Results:

  • MEL significantly inhibited LPS-induced upregulation of COX-2 in microglia.
  • MEL treatment led to reduced concentrations of PGE2, a downstream product of COX-2.
  • MEL decreased the activation of ERK1/2, JNK, p38 MAPK, and NF-κB signaling pathways.

Conclusions:

  • Melatonin attenuates the upregulation of COX-2 in LPS-stimulated microglia.
  • The anti-inflammatory effects of MEL on microglia are mediated through the inhibition of the MAPK/NF-κB signaling pathway.
Keywords:
Cyclooxygenase-2lipopolysaccharidemelatoninmicroglia

More Related Videos

Bronchoalveolar Lavage Exosomes in Lipopolysaccharide-induced Septic Lung Injury08:27

Bronchoalveolar Lavage Exosomes in Lipopolysaccharide-induced Septic Lung Injury

Published on: May 21, 2018

11.4K
Visualizing Lung Cellular Adaptations during Combined Ozone and LPS Induced Murine Acute Lung Injury14:48

Visualizing Lung Cellular Adaptations during Combined Ozone and LPS Induced Murine Acute Lung Injury

Published on: March 21, 2021

5.5K

Related Concept Videos

meta-Directing Deactivators: –NO2, –CN, –CHO, –⁠CO2R, –COR, –CO2H01:13

meta-Directing Deactivators: –NO2, –CN, –CHO, –⁠CO2R, –COR, –CO2H

All meta-directing substituents are deactivating groups. These substituents withdraw electrons from the aromatic ring, making the ring less reactive toward electrophilic substitution. For example, the nitration of nitrobenzene is 100,000 times slower than that of benzene because of the deactivating effect of the nitro group. The first step in an electrophilic aromatic substitution is the addition of an electrophile to form a resonance-stabilized carbocation. The energy diagrams for...
6.6K
Transcription Attenuation in Prokaryotes02:42

Transcription Attenuation in Prokaryotes

Transcriptional attenuation occurs when RNA transcription is prematurely terminated due to the formation of a terminator mRNA hairpin structure.  Bacteria use these hairpins to regulate the transcription process and control the synthesis of several amino acids including histidine, lysine, threonine, and phenylalanine. Transcription attenuation takes place in the non-coding regions of mRNA.
There are several different mechanisms used to attenuate transcription. In ribosome mediated...
18.2K
2° Amines to N-Nitrosamines: Reaction with NaNO201:20

2° Amines to N-Nitrosamines: Reaction with NaNO2

Secondary amines react with nitrous acid to form N-nitrosamines, as depicted in Figure 1. Nitrous acid, a weak and unstable acid, is formed in situ from an aqueous solution of sodium nitrite and strong acids, such as hydrochloric acid or sulfuric acid, in cold conditions. In the presence of an acid, the nitrous acid gets protonated. The subsequent loss of water results in the formation of the electrophile known as nitrosonium ion.
5.4K
SN2 Reaction: Kinetics02:14

SN2 Reaction: Kinetics

Kinetic Studies and Significance
In a chemical reaction, a relationship exists between the concentration of reactants and the rate at which the reaction proceeds. The study to measure this relationship is known as the kinetics of a chemical reaction. Kinetic studies are used to deduce the rate law of a chemical reaction, which provides information about the species involved during the transition state of the rate-determining step. Thus, kinetic studies help to derive the mechanism of a...
10.2K
SN2 Reaction: Mechanism02:27

SN2 Reaction: Mechanism

The kinetic studies of SN2 reactions suggest an essential feature of its mechanism: it is a single-step process without intermediates. Here, both the nucleophile and the substrate participate in the rate-determining step.
The presence of the more electronegative halogen in the substrate creates a polarized carbon-halide bond. The halide pulls the electron cloud generating an electrophilic center at the carbon atom. Thus, the carbon atom carries a partial positive charge while the halide has a...
17.2K
SN2 Reaction: Transition State02:26

SN2 Reaction: Transition State

An SN2 reaction of an alkyl halide is a single-step process in which bond formation between the nucleophile and the substrate and bond breaking between the substrate and the halide occurs simultaneously through a transition state without forming an intermediate.
When the nucleophile approaches the electrophilic carbon with its lone pairs, the halide acts as a leaving group and moves away with the electron-pair bonded to the carbon. Dotted partial bonds represent the bonds being formed or broken...
11.8K