The Empirical Studies On Addiction And Toxicity Of Mice Exposed To Environmental Tobacco Smoke,Nicotine And Smoke Tar Oil

Backgrounds:Smoking addiction has become a serious problem around the world. About 1/3 of the world adults are the smokers. WHO has given the passive smoking activity a conception as"exposed more than 15min Environmental Tobacco Smoke (ETS) during one day for a week", and thus it is inevitable to be a passive smoker as a world citizen. ETS could also be called as"secondhand smoke", which was a compound mixed with Nicotine,smoke tar oil and other 4000 substances from the smog breathed out by the smokers. From the epidemiologic survey, we could found that the rate of youth tobacco smokers is in accordance with that of passive smoking. The addictive substances in tobacco are used as the primary addicted drug for it could induce the human beings dependence and make a bad effect on the body and psychic health. However, people still know little about the purpose and mechanism of tobacco addiction and toxicity and deduce that ETS may become the main reason of youth smoking. Olfaction is the single sense pathway through into the brain and has the direct correlation with spontaneous movement of animals. The mechanism of addiction and learning–and-memory may involve the similar neurobiology backgrounds. Our research center has found out that little-doze toluene could induce addiction through olfactory pathway; eugeon could improve the learning-and-memory ability through olfactory pathway. Almost large number of passive smokers is surrounded by inferior chronic inhaling environment. The research was trying to set up a model of inferior chronic inhaling environment, in which the youth were inhaling some substances, aiming to explore the influence of ETS on smoking addiction through olfactory pathway and the influence on the body weigh and immunity.Objectives:1. To set up a model of inferior chronic inhaling environment,explore the relationship between ETS,NIC,STO exposed environment and the smoking addiction,find out the related mechanisms.2. To set up a olfactory epithelium model, explore the effect of olfactory pathway on the smoking addiction.3. To observe the changes of mice body weight growth rate,spleen index,thymus gland index/ alexin/ immune globulin level in peripheral blood serum after passive inhaling.4. To explore the influence of mice neuroethologic performances after inferior chronic inhaling ETS,Nic,STO.5 . To explore the mechanism through observing the changes of OERP and neurotransmitter on the smoking addiction-related brain areas.Methods:1 . ETS-exposed groups model: to evaluate the drug doze and the effective administration methods. The mice were selected and grouped into the following groups such as: the control group/ passive group/olfactory epithelium damaged plus passive smoking group. The mice were placed into the ETS-exposed bench for 1-3 months as the inferior chronic inhaling model. The neuroethology experiments such as: CPP,autonomic activities test,hole-board experiment and Morris water maze were used to test the influence of nervous excitation and space learning-and-memory ability after inhaling 4w and 8w later. 2. During the period of inhaling Nic and STO, the mice were grouped into: the control group,Nic inhaling group,olfactory epithelium damaged plus Nic inhaling group; STO inhaling group,olfactory epithelium damaged plus STO inhaling group. The neuroethology experiments such as CPP and other tests listed above were used after inhaling 8w later.3. Testing and recording the changes of mice body weight growth rate,spleen index,thymus gland index,alexin,immune globulin level in peripheral blood serum after inhaling ETS,Nic,STO. Through immunoturbidimetry (ITM), we tested content of C3,C4,IgA,IgG in periphery arterial blood serum on the ETS–exposed group; the content of IgA,IgG in blood serum on the Nic inhaling group,the epithelium damaged plus passive smoking group ,trying to explore the influence on non-specific immunity function.4 . Through stereotaxic apparatus , localize the region using the PowerLab Multichannel physiology massage collection and processing system to record the changes of potentials on the OB/NA/SN after inhaling ETS/NIC5. Through immunohistochemistry methods, we tested the expression of GABA,nAChR and NMDAR on the OB,CC,HIP and other brain areas.Results:1.The testing results of mice addiction: No statistical significance could be come up with on the 4w time long ETS-exposed mice(P>0.05); The time of staying in the white box was longer than the control group(P<0.05) and the obvious addiction abstinent symptom could be observed on the 8w time long ETS-exposed mice(P< 0.05). No statistical significance ON the CPP testing results could be come up with between the ETS plus olfactory epithelium damaged group,Nic-exposed mice group,the STO-exposed group and the control group(P>0.05).2.The neuroethology experimental results:(1) the results of autonomic activities hole-board experiment : obvious increasing autonomic activities could be observed between the ETS-exposed group and the control group(P<0.05),obvious decreasing frequencies could be observed on the visiting-hole experiment(P<0.05). The obvious increasing frequencies could be observed on the Nic-exposed group in the autonomic activities and autonomic activities hole-board experiments. On the contrary, no obvious changes could be observed on the other groups compared with the control group.(2) the results of morris water maze experiment: the latency of parameters were recorded much higher for the first time on the ETS-exposed group,olfactory epithelium damaged plus passive smoking group and the STO-exposed group than the control group(P<0.05); The average swimming speed parameter on the model groups listed above was lower than the control group(P<0.05); the frequencies of passing through the safe platform on the ETS-exposed group,the epithelium damaged plus NIC smoking group/STO exposed group were lower than the control group(P<0.05)。.3.(1)The body weight growth rate parameter on the ETS-exposed group,STO exposed group were much lower than the control group(P<0.05);the spleen index on the ETS-exposed group was much lower than the control group(P<0.05);(2)The content of C3,C4,IgA,IgG in periphery arterial blood serum on the ETS–exposed group was much lower than the control group(P<0.05); The content of IgA,IgG in blood serum on the Nic inhaling group,the epithelium damaged plus passive smoking group was much lower than the control group(P<0.05). 4.The results of OERP on olfactory bulb(OB),nucleus accumbens septi (NA),substantia nigra(SN):(1) The results of OERP on OB:Similar waveshape without obvious changes on frequencies and amplitude of vibration (less than 0.1V) could be found on olfactory nerve-evoked field potentials when the mice were forced to inhale nicotine. The changes of double-shoulder-shaped wave into single- shoulder-shaped wave without obvious changes on frequencies(less than 1/2) and the amplitude of vibration when the mice were forced to inhale ETS. (2) The results of OERP on NA: the amplitude of vibration were added by 0.075V and the frequencies were 1/2 lower when the mice were forced to inhale nicotine. Compared with the spontaneous potential parameters, olfactory nerve-evoked field potentials involved higher amplitude of vibration and lower frequencies without too much changes. (3) The results of OERP on SN: The changes of positive-orientation-shaped wave into negative- orientation-shaped wave with amplitude of vibration added by 0.5v and 1/2 less frequencies could be observed when the mice were forced to inhale nicotine. Compared with the spontaneous potential parameters, olfactory nerve-evoked field potentials involved little changes on the amplitude of vibration and obvious lower frequencies.5. The immunohistochemistry results:(1) the expression of GABA on the mice cerebral cortex (CC) and the hippocampus(Hip) could be observed much higher on the ETS-exposed group than the control group;no obvious changes could be found on Nic-inhaling group compared with the control group. (2) the expression of nAChR on CC could be found much higer on the ETS-exposed group than the control group;no obvious changes could be found on Nic-inhaling group compared with the control.(3) the expression of NMDAR (Glu receptors) on the CC and striate cortex could be observed much higher on the ETS-exposed group,NIC-inhaling group and the control group. Conclusions:1. Long-term ETS-exposed environment could induce mice addiction through the olfactory pathway.2. Long-term ETS-exposed and STO-exposed environment could obviously lessen the learning-and-memory ability on the mice and make an effect on the neuroethology.3. Long-term ETS-exposed and STO-exposed environment could cut down the body weight growth rate and non-specific immunological function on the mice.4. Long-term ETS-exposed and STO-exposed environment could induce specific OERP changes on the OB,NA and SN.5. Long-term ETS-exposed and STO-exposed environment could induce the changes on the expression of neurotransmitter and receptors on OB,CC,the thalamencephal and the other areas of the brain.