Quercetin Protects Human Thyroid Cells against Cadmium Toxicity

Area of Science:

• Toxicology
• Cell Biology
• Natural Products Chemistry

Background:

• Heavy metal exposure poses significant health risks.
• Cadmium chloride (CdCl2) is a toxic heavy metal with known adverse effects.
• Natural compounds are explored for their protective properties against heavy metal toxicity.

Purpose of the Study:

• To investigate the toxic effects of cadmium chloride on normal thyroid cells (Nthy-ori-3-1).
• To elucidate the molecular mechanisms of cadmium-induced thyroid cell damage.
• To evaluate the protective potential of quercetin against cadmium toxicity in thyroid cells.

Main Methods:

• Cell culture of immortalized, non-tumorigenic thyroid cells (Nthy-ori-3-1).
• Exposure of cells to varying concentrations of cadmium chloride (CdCl2).
• Assessment of cell viability, reactive oxygen species (ROS) production, lipid peroxidation, and protein expression (phospho-ERK, GRP78).
• Treatment with quercetin to determine protective effects.

Main Results:

• Cadmium chloride suppressed thyroid cell growth in a dose- and time-dependent manner (IC50 ~10 μM).
• CdCl2 exposure led to decreased phospho-ERK levels, increased ROS production, lipid peroxidation, and GRP78 expression.
• Quercetin supplementation reversed CdCl2-induced growth inhibition, restored ERK phosphorylation, reduced ROS and lipid peroxidation markers (MDA), and lowered GRP78 expression.

Conclusions:

• Cadmium chloride induces toxicity in normal thyroid cells through mechanisms involving suppressed ERK phosphorylation, oxidative stress, and ER stress.
• Quercetin demonstrates a significant protective effect against cadmium-induced damage in normal thyroid cells.
• This study highlights quercetin as a potential therapeutic agent for mitigating cadmium toxicity in thyroid tissues.