Background to the study: Nicotine is the main active component of cigarettes. Smoking has been associated with higher prevalence of abnormalities in lipid metabolism. This study investigated the effects of nicotine withdrawal on the plasma lipid profile of wistar rats fed with high-fat diet (HFD). Methodology: The experiment involved 24 male wistar rats separated into 3 groups of 8 rats each. All the animals were placed on high-fat diet in addition to their respective doses of nicotine as follows; Groups 1, 2 and 3 received 200µg/kg, 400µg/kg and 800µg/kg of nicotine oral solution respectively. The experiment was performed in two phases. In the first phase, the animal groups were placed on their respective doses of nicotine solution for 4 weeks. Thereafter, 4 animals in each group were sacrificed and blood samples collected to determine their nicotine exposed plasma lipid profile. In the second phase of the experiment, nicotine was discontinued in all the groups. The remaining 4 animals in each group continued without nicotine for the next four weeks after which they were sacrificed and blood samples collected to determine their nicotine withdrawal plasma lipid profile. Results: The results showed that the levels of total cholesterol (TC), high-density lipoprotein (HDL) and low-density lipoprotein (LDL) increased significantly while there was no significant change in triglycerides (TG) concentration four weeks after withdrawal of 200µg of nicotine compared to the exposed groups. However, following cessation of 400µg and 800µg respectively of nicotine, the plasma levels of TC, TG, HDL and LDL increased significantly compared to their exposed groups suggestive of an initial suppression of the lipid profile parameters with nicotine exposure. Conclusion: Conclusively, higher concentrations of nicotine caused significant suppression of TC, TG, HDL and LDL with significant reversal in the four weeks preceding exposure. Therefore, in quitting smoking, it is important to reduce or stop the consumption of high-fat diet in the immediate periods following cessation of nicotine. The study also recommends that nicotine cessation programs should be accompanied by improved physical activity to prevent possible post-cessation excessive weight gain.

Keywords: Nicotine, withdrawal, Plasma lipid profile, high-fat diet, wistar rats.