孕期尼古丁暴露子代大鼠饲喂高脂饮食对下丘脑-垂体-肾上腺轴敏感性的影响及发生机制  

Prenatal nicotine exposure induced high sensitivity of hypothalamic-pituitary-adrenal axis in offspring rats under high fat diet

作　　者：何厦 徐丹[1,2] 卢娟[1] 董婉婷[1] 胡泽文[1] 汪晖[1,2] 

机构地区：[1]武汉大学基础医学院药理学系,湖北武汉430071 [2]发育源性疾病湖北省重点实验室,湖北武汉430071

出　　处：《中国药理学与毒理学杂志》2017年第1期80-86,共7页Chinese Journal of Pharmacology and Toxicology

基　　金：国家自然科学基金(81220108026);国家科学自然基金(81371483);国家科学自然基金(81430089)~~

摘　　要：目的观察孕期尼古丁暴露(PNE)所致子代大鼠高脂饮食下下丘脑-垂体-肾上腺(HPA)轴应激高敏感性改变,并探讨其发生机制。方法受孕Wistar大鼠从孕9~20 d sc给予尼古丁2 mg·kg-1。自然出生仔鼠断奶后给予高脂饮食喂养至20周(PW20),其中一半仔鼠从PW17至PW20给予3周不可预计性慢性刺激(UCS)。HE染色观察组织形态学改变,放免试剂盒和ELISA分别检测大鼠血清促肾上腺皮质激素(ACTH)及皮质酮(CORT)水平,PCR检测ACTH释放激素(CRH)、精氨酸加压素(AVP)、囊泡谷氨酸转运蛋白2(VGlu T2)、谷氨酸脱羧酶65(GAD65)、盐皮质激素受体(MR)、糖皮质激素受体(GR)和谷氨酸脱羧酶67(GAD67)等相关基因的m RNA表达。结果正常对照组雌、雄仔大鼠经UCS刺激后,血清ACTH和CORT分别升高了1.96倍(P<0.01),1.63倍(P<0.01)和3.24倍(P<0.01),3.54倍(P<0.01),PNE组雌、雄仔大鼠经UCS刺激后,血清ACTH和CORT分别升高了3.96倍(P<0.01),3.04倍(P<0.01)和5.98倍(P<0.01),5.22倍(P<0.01)。与UCS处理的正常对照组仔大鼠相比,UCS处理的PNE组雌、雄仔大鼠下丘脑AVP m RNA表达分别升高了2.04倍(P<0.01)和1.13倍(P<0.05),雌性下丘脑CRH m RNA表达和VGlu T2/GAD65 m RNA比值分别升高了2.49倍(P<0.01)和1.14倍(P<0.01)。全部PNE组雌、雄仔大鼠海马各区均出现不同程度的病理损伤,表现为神经元数量减少、排列稀疏和细胞间隙增大。与无UCS处理的正常对照组相比,无UCS处理的PNE雌、雄仔大鼠海马MR/GR m RNA比值分别降低了88.0%和86.0%(P<0.01),GAD67 m RNA表达分别升高了1.38倍和1.97倍(P<0.05);与UCS处理的正常对照组相比,UCS处理的PNE组雌性仔大鼠海马GAD67 m RNA表达升高了2.17倍(P<0.05)。结论 PNE可致高脂饮食成年子代大鼠HPA轴应激高敏感性发生,其机制可能与海马MR/GR比值失衡、GAD67表达上调,进而介导下丘脑局部潜在兴奋性增加有关。OBJECTIVE To observe prenatal nicotine exposure（PNE） induced high sensitivity of hypothalamic-pituitary-adrenal（HPA） axis in offspring rats which were fed with a high-fat diet, and to explore the mechanism. METHODS Nicotine（2 mg·kg-1per day） was injected subcutaneously to pregnant Wistar rats from gestational day（GD） 9 to GD20,and then the young rats were naturally delivered.After weaning, half of the offspring was fed with a high-fat diet until postnatal weeks（PW） 20. The others were exposed to unpredictable chronic stress（UCS） from PW17 to PW20. The pathological changes in the hippocampus were analyzed by HE staining. The blood concentration of adrenocorticotropic hormone（ACTH） and corticosterone（CORT） was detected by RIA kits and ELISA kits, respectively. Meanwhile,real-time PCR was used to detect the m RNA expression of ACTH releasing hormone（CRH）, arginine vasopressin（AVP）, vesicular glutamate transporter 2（VGlu T2）, glutamic acid decarboxylase 65（GAD65）, mineralocorticoid receptor（MR）,glucocorticoid receptor（GR） and glutamic acid decarboxylase67（GAD67）. RESULTS In the normal control group,UCS treatment increased the level of serum ACTH and CORT 1.96 and 3.24 times in female rats,but 1.63 and 3.54 times in male rats. In the PNE group, UCS treatment increased the level of serum ACTH and CORT 3.96 and 5.98 times in female rats, but 3.04 and 5.22 times male rats. PNE increased the m RNA expression of AVP in the female and male rats 2.04 and 1.13 times in UCS treatment control group, and the m RNA expression of hypothalamus CRH and the ratio of VGLu T2/GAD65 were increased 2.49 and 1.14 times in female rats, respectively.Furthermore, the nicotine group exhibited histological changes to different degrees in the hippocampus and dentate gyrus area of the hippocampus. In the female and male nicotine groups, the m RNA ratio of hippocampal MR/GR decreased by 88.0% and 86.0% in comparison with the normal control group without UCS, and the m RNA expression of

关 键 词：尼古丁 海马 下丘脑-垂体-肾上腺轴 高敏感性 

分 类 号：R114[医药卫生—卫生毒理学]