[Animal experiment]-The effect of cigarette smoke exposure on plasma nicotine and cotinine in male rats

  Objective: To study the intrinsic exposure level of tobacco in vivo by measuring the plasma nicotine and cotinine content of smoking rats.

  Method: 160 clean SD male rats were randomly divided into low, medium and high dose groups for 2, 4, 6, 8 and 12 weeks, with 10 control groups in each group. Expose the respiratory tract statically. Once a day, the exposure period is 2, 4, 6, 8, 12 weeks. Observe the general toxic effects of rats, and use gas chromatography-mass spectrometry to detect the levels of nicotine and cotinine in the plasma of smoking rats.

  Result: After the third week, the rats in the group exposed to cigarette smoke gradually began to feel symptoms such as intermittent cough, increased abdominal breathing, and nasal sounds. The longer the exposure time, the more obvious the symptoms, the higher the degree of exposure, and the longer the exposure period. The longer the weight, the more obvious the weight loss of the rats, which was statistically significant compared with the blank control group (P\u003c0.01). The retention time of rat plasma nicotine is 7.5-8.5 minutes, and the exposure dose increases with the increase of exposure time. Compared with the blank control group, the nicotine content in rat plasma increased (155±56.65) ng/mL; the retention time of cotinine in rat plasma was 11.5-12.5 minutes; long-term exposure compared with the blank control group ( Compared with 340±41.97) ng/mL, the exposure of rats increased, and the content of cotinine in plasma increased, showing a dose-response relationship. The difference in cotinine content between different exposure times was significant (P\u003c0.05), and there was an interaction between exposure time and exposure dose (P\u003c0.05).

  Conclusion: Exposure to cigarette smoke will cause varying degrees of damage to the body of mice. The concentration of cotinine in rat plasma can effectively reflect exposure to tobacco smoke and shows a good dose-response relationship.