Evaluation the Effect of Nicotine Injection on the Lungs of Mice

Background: Nicotine is the chief addictive substance in cigarette smoking which conceder as the main cause of mortality worldwide. 
Aims: Through the current in vivo study, we tried to evaluate the harmful effect of nicotine injection on the lungs of mice. 
Materials and Methods: A total of 40 healthy male mice were divided into four groups of 10 mice each, injected subcutaneously with 0.1 ml of (1 mg/kg) nicotine for 5 days a week for (8, 12, and 16) weeks, whereas the control group injected with 0.1 ml of normal saline. The mice were sacrificed, lungs were isolated and divided into two parts, the first for measurement malondialdehyde (MDA) and glutathione (GSH), the second was subjected to histopathological examination. 
Results: The results showed that the levels of MDA were significantly elevated (P ≤ 0.01) in all work groups and the mice of Group D had the highest MDA value (23.13 ± 3.4 nmol/ml) with statistically significant difference (P ≤ 0.01), and GSH levels were significantly decreased (P < 0.01) in all workgroups, the Group D had the lowest value (6.77 ± 1.33 mM/ml) with statistically significant difference (P ≤ 0.01), also the results clarified that nicotine injection was caused a pathological effect in mice lung tissues such as alveoli damage and emphysema, congestion of blood vessels, hemorrhage, alveolar edema, lung fibrosis, lymphocytes infiltration, and these effects were graded in terms of severity depending on the injection period of nicotine. 
Conclusion: It can be concluded that the nicotine injection causes significant changes in lung tissues and oxidant markers levels (MDA and GSH).