Metal-Associated Particulate Matter (PM_2.5) Induces Cognitive Dysfunction: Polygonum multiflorum Improves...

Area of Science:

• Neuroscience
• Environmental Health
• Pharmacology

Background:

• Fine particulate matter (PM_2.5) exposure is linked to cognitive dysfunction.
• PM_2.5 induces neuroinflammation, oxidative stress, and mitochondrial dysfunction.
• Heavy metals in PM_2.5 contribute to these detrimental effects.

Purpose of the Study:

• To evaluate the neuroprotective effects of Polygonum multiflorum extract (EPM) against PM_2.5-induced cognitive impairment.
• To investigate the mechanisms underlying EPM's protective actions.
• To standardize EPM using HPLC for its bioactive compound, tetrahydroxystilbene glucoside (TSG).

Main Methods:

• A mouse model was used to assess PM_2.5-induced cognitive deficits.
• Behavioral tests evaluated learning and memory.
• Biochemical assays measured oxidative stress markers (SOD, GSH, MDA, mtROS), mitochondrial function (membrane potential, ATP), and inflammatory pathways (TLR4-MyD88-NF-κB, JNK).
• Blood-brain barrier integrity and synaptic plasticity markers (BDNF/TrkB) were analyzed.
• Cholinergic system components (ACh, AChE, ChAT) were quantified.
• High-performance liquid chromatography (HPLC) identified tetrahydroxystilbene glucoside (TSG).

Main Results:

• EPM treatment significantly improved learning and memory in mice exposed to PM_2.5.
• EPM restored redox homeostasis by increasing SOD and GSH and decreasing MDA and mtROS.
• Mitochondrial function, including membrane potential and ATP levels, was recovered.
• EPM inhibited neuroinflammation via the TLR4-MyD88-NF-κB pathway and maintained blood-brain barrier integrity.
• Neuronal apoptosis was modulated via the JNK pathway, reducing amyloid-beta and phosphorylated tau accumulation.
• Synaptic plasticity and cholinergic neurotransmission were preserved.
• HPLC confirmed TSG as a key component of EPM.

Conclusions:

• Polygonum multiflorum extract (EPM) demonstrates significant neuroprotective effects against PM_2.5-induced cognitive dysfunction.
• EPM mitigates cognitive impairment by combating oxidative stress, neuroinflammation, mitochondrial dysfunction, and neuronal apoptosis.
• EPM holds promise as a functional food for preventing or treating cognitive deficits associated with PM_2.5 exposure.