Effect of passive smoking on content of nerve growth factor in cerebellar cortex of fetal rats and the interventional effect of taurine / 中国组织工程研究

ABSTRACT

BACKGROUND: Reported about passive smoking on development of nervous system are rare and it is lack of preventive and therapeutic measures.Previous animal experiments proved that passive smoking at pregrancy could decrease content of Nerve growth factor (NGF) in hippocampal tissue and eliminate abilities of learning of fetal rats. Cerebellar cortex contain high levels of NGF at embryonic phase. Passive smoking decrease content of NGF in cerebellar cortex. Brain of mammalis animal is full of taurine which is released by neuron and neuroglia cell to maintain normal activities in cerebral tissue. Inhibitory synthesis and ingestion of taurine can cause disfunction.Therefore, a certain level of taurine is possibly correlated with expression of NGF gene in embryoids. However, the decrease of NGF content in cerebellar cortex may be one of factors for brain injury of fetal rats.OBJECTIVE: To investigate the mechanism of brain injury induced by passive smoking in fetal rats and the interventional effect of taurine.DESIGN: Randomized controlled animal study.SETTING: Fenyang College of Shanxi Medical University.MATERIALS:Twenty-one 2-month-old female Wistar rats,weighing 150-210 g, were randomly divided into 3 group with 7 rats in each group,including passive smoking group, passive smoking+taurine group and normal control group. All rats in the three groups were treated till naturalpartrition from the second day of cyesis. Rats in the passive smoking group were suffered from successively experimental smoking after intragastrical administration with 0.65 mL/ampoule saline; rats in the passive smoking+taurine group were intragastrically administrated with 500 mg/kg taurine before smoking rats in the normal contrl group did not smoke and were intragastrically administrated with 0.65 mL/ampoule saline every day.METHODS: Newborn rats were weighed and then their heads were cut off. Rapidly, brains were separated,weighed,boiled in boiling saline for 5 minuters. Then, cerebellum was separated. Content of NGF in cerebellar tissue of fetal rats were measured with immune-radio technique. Changes of NGF protein in cerebellar cortex were regarded as the indexes to analyze the effect of passive smoking and taunine on them.MAIN OUTCOME MEASURES: Comparisons of body mass, cerebral mass and the contents of NGF protein.RESULTS: A total of 147 fetal rats were involved in the final analysis,Levels of body mass, cerebral mass and the contents of NGF protein were markedly lower in passive smoking group than those in normal control group and passive smoking + taurine group (P ＜ 0.001). There was no significant difference of the three indexes between passive smoking + taurine group and normal control group (P ＞ 0.05).CONCLUSION: Passive smoking is a possible factor for decreasing level of NGF in cerebellar cortex of fetal rats, and taurine may protect brain injury induced by passive smoking.