Nicotine enantiomers and oxidative stress

Area of Science:

• Toxicology
• Cell Biology
• Biochemistry

Background:

• Nicotine influences numerous cellular functions, including gene expression, hormone secretion, and enzyme activity.
• Understanding the differential toxicity and cellular effects of nicotine enantiomers is crucial for assessing its biological impact.

Purpose of the Study:

• To characterize the toxicity of nicotine enantiomers.
• To evaluate the capacity of nicotine enantiomers to induce oxidative stress in Chinese hamster ovary (CHO) cells.

Main Methods:

• Colony formation assay to assess cell viability and toxicity.
• Measurement of glutathione (GSH) and malondialdehyde (MDA) levels to evaluate oxidative stress.
• Assay of lactate dehydrogenase (LDH) activity to determine cell membrane integrity.
• Assessment of the protective effects of superoxide dismutase (SOD) and catalase (CAT) against nicotine-induced damage.

Main Results:

• (-)-Nicotine exhibited significantly higher toxicity compared to (+)-nicotine and racemic (+/-)-nicotine.
• Exposure to (-)-nicotine led to a substantial decrease in cellular glutathione (GSH) levels and a significant increase in malondialdehyde (MDA) levels.
• Increased lactate dehydrogenase (LDH) activity indicated compromised cell membrane integrity in nicotine-treated cells.
• The radical scavenging enzymes SOD and CAT reversed the nicotine-induced increase in LDH activity, suggesting a role for free radicals.

Conclusions:

• (-)-Nicotine is the more potent enantiomer in terms of toxicity and induction of oxidative stress in CHO cells.
• Nicotine-induced cell membrane damage is likely mediated by free radical generation.
• These findings highlight the enantiomer-specific toxicity of nicotine and its contribution to oxidative cellular damage.