香烟烟雾暴露对雄性大鼠的生殖毒性及仔鼠学习记忆的影响

Recent survey data indicate an upward trend in the rate of smoking cigarettes，cigarettes are eroding people's health and economic wealth , and deeply influenced the next generation. Our previous study also showed that smoking would cause some degree of damage on male reproductive function and affect growth and development of offspring, learning and memory in which the offspring worth exploring. But male reproductive toxicity mechanism caused by smoking is not clear, while an animal model of smoking is lack of a unified specification, cigarette smoke exposure dose in vivo and dose-response relationship between cigarette smoke exposure dose and Recent survey data indicate an upward trend in the rate of smoking cigarettes，cigarettes are eroding people's health and economic wealth , and deeply influenced the next generation. Our previous study also showed that smoking would cause some degree of damage on male reproductive function and affect growth and development of offspring, learning and memory in which the offspring worth exploring. But male reproductive toxicity mechanism caused by smoking is not clear, while an animal model of smoking is lack of a unified specification, cigarette smoke exposure dose in vivo and dose-response relationship between cigarette smoke exposure dose and metabolites to be explored. This study intends to integrate different of cigarette exposure dose and different exposure times, establish superior animal model of human smoking. To determinate nicotine and cotinine content changes in plasma of passive smoking male rat, discuss cigarette smoke exposure dose in vivo and dose-response relationship between cigarette smoke exposure dose and metabolites, determine exposure biomarkers of smoking. To detect reproductive toxicity and genotoxicity of passive smoking parent, explore the effects and mechanisms of parent smoking on learning and memory in the offspring, to provide experimental data and scientific evidence for further understand and predict genetic hazards of smoking and further epidemiological studies.

近期调查数据表明我国吸烟率呈上升趋势，香烟正在侵蚀着人们的健康和财富，并将深深影响下一代。本课题组前期研究显示吸烟会造成雄性小鼠生殖功能损伤，并会影响仔鼠生长发育，其中对仔鼠学习记忆的影响值得探讨。目前吸烟所致雄（男）性生殖毒性的机制尚不明确，吸烟动物模型的建立也缺乏统一的规范，香烟烟雾在体内的内暴露水平及吸烟量与体内代谢产物之间的剂量-效应关系有待探讨。本研究拟将香烟不同染毒剂量融合不同染毒时间，建立更符合人类吸烟状态的动物模型；测定香烟烟雾暴露对雄性大鼠血浆中尼古丁及可替宁水平的影响，探讨香烟烟雾在体内的内暴露水平及吸烟量与体内代谢产物之间的剂量-效应关系，确定吸烟的接触生物学标志；检测父代被动吸烟的生殖毒性和遗传毒性，并进一步探讨父代吸烟对仔鼠学习记忆的影响及机制，为深入理解和预测吸烟的遗传性危害以及进一步进行人群流行病学研究提供实验数据及科学依据。

调查数据表明我国吸烟率呈上升趋势，香烟正在侵蚀着人们的健康和财富，并将深深影响下一代。世界卫生组织(WHO)估计，目前全世界共有6000～8000万对夫妇患不育症，而且有逐年增长的趋势，其中男性不育症占一半左右，推测原因可能与环境污染和不良生活习惯等因素有关，其中吸烟对男性生殖机能的不良影响成为研究热点。本研究构建不同暴露时间和不同暴露剂量的雄性大鼠吸烟模型，评估吸烟对雄性大鼠的生殖毒性，进一步探讨吸烟引起生殖毒性的分子生物学机制；通过Morris水迷宫实验测定不同性别子代空间学习记忆能力的改变，并在分子生物学层面探讨父代吸烟引起子代学习记忆能力改变的机制。结果显示吸烟可引起雄性大鼠睾丸组织结构损伤，精子生成减少，精子畸形率升高，雌鼠受孕率及子代出生数量降低，其分子生物学机制可能是吸烟使睾丸组织发生了不可逆性的损伤，损伤机制包括睾丸组织中过度的氧化应激反应，上调的死亡受体Fas/FasL凋亡信号通路和抑制的wnt/β-catenin增殖通路。父代吸烟可导致子代空间学习记忆能力受损，且对雄性子代影响更明显，引起这种表现的可能原因是父代吸烟引起了雄性子代海马组织中氧化和抗氧化系统失衡；BDNF蛋白表达下调；父代吸烟使子代海马组织中凋亡率增加，同时激活了wnt/β-catenin增殖通路，凋亡与增殖之间相抗衡使子代未出现更为明显的学习记忆损伤。此研究为父源性香烟暴露引起的子代学习记忆功能障碍提供了数据支撑和理论依据，为下一步的机制研究奠定基础。