| Our country is a big country of tobacco,in which the people of smoking is great.The harmful matter in tobacco finally enter blood circulation through aspiratory system and digest system,inducing many system's pathological changes.The woman smoking lead to the decline of procreation ability,the abnormity of chromosome and the increasing of the ratio of abortion .The harm of passive smoking greatly exceed initiative smoking.It lead to the obvious toxicity of embryo.Many research only rest on the whole period of pregnant,b-ut the research to distinct pregnant is little .To study the phase of mostly effect of tobacco and interfering it ,we use pregnant Wister-rat to discuss the harm of smoking in distinct pregnant. Purpose: To study the effect to embryo growth and placenta of passive smoking in distinct pregnant and c-fos gene expression of embryo brain,to find out nicotian embryo toxicity to distinct pregn-ant rat and the relation between pregnant period and c-fos gene expression.Method:Making the model of passive smoking in distinct pregnancy,we use HE coloration and reverse transcription polymerase chain reaction to measure the pathology changes of the placenta and brain and c-fos gene expression in hippocampi.Result:(1)the ratio of absorbable embryo and died embryo in A group is 15.58%,and the ratio of B group is 4.87%.They increase evidently comparing with C group (P<0.01,P<0.05);They increase evidently comparing with D group ,too.(P<0.01,P<0.05) ;C group differ little comparing with D group(2)The middle weight and the average placenta weight of A group is 3.75±0.12g and 0.593±0.183mg,it is 3.42±0.10g and0.574±0.348mg in B group . They increase evidently comparing with C group (P<0.01,P<0.05);They increase evidently comparing with D group,too.(P<0.01,P<0.05);A group differ evidently comparing with B group(P<0.05); C group differ little comparing with D group(P>0.05)(3)The average height and trailheight of B group is 3.47±0.14mm and 1.02±0.56mm, and They dicline evidently comparing with the other groups (P<0.05).(4)The ratio of IUGR in B group is 28.2%(22/78),increasing evidently comparing with the other groups (P <0.05)(.5)The pathology changes of placenta and brain in B group is greatest。(6)The c-fos gene expression in hippocampi in B group is 0.42±0.09,and it increasing evidently comparing with other groups (P<0.05)。Conclusion:Embryo toxicity leaded by passive smoking,infection to placenta and brain and c-fos gene expression relate to pregnant period.⑴Embryo growth in uterus by tobacco have time-domino effect relation.Tobacco is commix smog of much injurant,affecting embryo growth by many mechanism.Embryo growth is disparted to three stages.The second stage and the initial of the third stage is the sensitive stage of embryo growth,being the most liable to be affected by environment.The two stages are eight-thirteen days in rat(five-eight weeks in human being).Wegroup the rat basing on this,in favor of comparing and differentia-ting embryo toxicity and behaving of embryo growth in different pregnant period in uterus. The result show that embryo toxicity is died embryo,absorbable embryo and IUGR.By comparing , died embryo and absorbable embryo in A group is greatest. Embryo toxicity in B group is IUGR.Its middle weight,average height and trailheight differ form the other groups. This show that embryo growth in uterus by tobacco have time-domino effect relation , and different pregnant period have different behaving of embryo growth. This embryo toxicity in pregnant forepart exceed it in pregnant afternoon.So the pregnant woman should avoid passivity smoking in five-eight weeks after gestation,which has important meaning to prevent died embryo,absorbable embryo and IUGR⑵Passivity smoking in pregnant period may lead to pathology changes of placenta and brain tissue ,which is the most evident in eight-thirteen days after pregnancy.The result shows that pathology changes of placenta in B group is the most evident. It is obvious that chronic non-special inflammation as fibrotic putrescence and lymphocyte and plasm cell soakage in labyrinth layer and floor layer ,and tiny villus become short and thick evidently in decidua layer.Although this is an anoxic having ,but this make blood's efficient exchange lower.The average placenta weight,The middle weight,The average height and trailheight of B group differ evidently.But the ratio of IUGR increase evidently .These also show that pathologychanges of placenta relate to the ratio of IUGR .These show that the occur of IUGR have similar mechanism with human being. ⑶Passive smoking in pregnant period lead to c-fos gene excessive expressing,which is the most obvious in eight-thirteen weeks after pregnancy.The result show that there is lacking oxygen and dropsical behaving as glia cell hyperplasia and glia network loosen in eight cases from B group.At the same time,we can see the morphological changes as chromatin border collection,crinking and concreting in nucleus.It is the most obvious in B group.Discussing the mechanism,it maybe relate to lacking blood and oxygen,maybe relate to decreasing of zinc absorbability ,maybe injure the germ plasm DNA,maybe make cell abruption resort in G0 G1 period ,which restrain cell growth .In our experiment,we discover cell languish in pathology of the brain tissue.This shows that smoke can evocate cell languish ,which lead to injure brain tissue.This discovery make investigation of smoke influencing come into molecule field.C-fos gene is one of the uppermost rapid reactive gene in nerve centre.When stimulation leading to brain cell's damage,c-fos gene expression increase obviously and fasten cell's damage.The result show which is more obvious than the other group that lacking oxygen and edema of brain tissue and c-fos gene expression increase in B group.This also show that eight-thirteen days after pregnant is a time –window ,in which smoke may lead to brain tissue damage.We may intervene and...
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