雌激素对原发性和内分泌性高血压大鼠大脑的保护作用。
Protective effect of estrogens on the brain of rats with essential and endocrine hypertension.
作者信息
De Nicola Alejandro F, Pietranera Luciana, Bellini Maria José, Goya Rodolfo, Brocca Maria Elvira, Garcia-Segura Luis Miguel
出版信息
Horm Mol Biol Clin Investig. 2010 Dec 1;4(2):549-57. doi: 10.1515/HMBCI.2010.044.
Estrogen neuroprotection has been shown in pathological conditions damaging the hippocampus, such as trauma, aging, neurodegeneration, excitotoxicity, oxidative stress, hypoglycemia, amyloid-β peptide exposure and ischemia. Hypertensive encephalopathy also targets the hippocampus; therefore, hypertension seems an appropriate circumstance to evaluate steroid neuroprotection. Two experimental models of hypertension, spontaneously hypertensive rats (SHR) and deoxycorticosterone (DOCA)-salt hypertensive rats, develop hippocampal abnormalities, which include decreased neurogenesis in the dentate gyrus, astrogliosis, low expression of brain-derived neurotrophic factor (BDNF) and decreased number of neurons in the hilar region, with respect of their normotensive strains Wistar Kyoto (WKY) and Sprague-Dawley rats. After estradiol was given for 2 weeks to SHR and DOCA-treated rats, both hypertensive models normalized their faulty hippocampal parameters. Thus, estradiol treatment positively modulated neurogenesis in the dentate gyrus of the hippocampus, according to bromodeoxyuridine incorporation and doublecortin immunocytochemistry, decreased reactive astrogliosis, increased BDNF mRNA and protein expression in the dentate gyrus and increased neuronal number in the hilar region of the dentate gyrus. A role of local estrogen biosynthesis is suggested in SHR, because basal aromatase mRNA in the hippocampus and immunoreactive aromatase protein in cell processes of the dentate gyrus were highly expressed in these rats. Estradiol further stimulated aromatase-related parameters in SHR but not in WKY. These observations strongly support that a combination of exogenous estrogens to those locally synthesized might better alleviate hypertensive encephalopathy. These studies broaden estrogen neuroprotective functions to the hippocampus of hypertensive rat models.
雌激素的神经保护作用已在多种损害海马体的病理状况中得到证实,如创伤、衰老、神经退行性变、兴奋性毒性、氧化应激、低血糖、淀粉样β肽暴露和缺血。高血压脑病也会影响海马体;因此,高血压似乎是评估类固醇神经保护作用的合适情形。两种高血压实验模型,即自发性高血压大鼠(SHR)和脱氧皮质酮(DOCA)-盐性高血压大鼠,相较于其正常血压品系的Wistar Kyoto(WKY)大鼠和Sprague-Dawley大鼠,会出现海马体异常,包括齿状回神经发生减少、星形胶质细胞增生、脑源性神经营养因子(BDNF)表达降低以及海马门区神经元数量减少。在给SHR和DOCA处理的大鼠给予雌二醇2周后,两种高血压模型的海马体参数异常均恢复正常。因此,根据溴脱氧尿苷掺入和双皮质素免疫细胞化学检测,雌二醇治疗对海马体齿状回的神经发生有正向调节作用,减少了反应性星形胶质细胞增生,增加了齿状回中BDNF mRNA和蛋白表达,并增加了齿状回海马门区的神经元数量。在SHR中提示了局部雌激素生物合成的作用,因为这些大鼠海马体中的基础芳香化酶mRNA以及齿状回细胞突起中的免疫反应性芳香化酶蛋白高度表达。雌二醇进一步刺激了SHR中与芳香化酶相关的参数,但对WKY大鼠没有作用。这些观察结果有力地支持了外源性雌激素与局部合成的雌激素联合使用可能能更好地缓解高血压脑病。这些研究将雌激素的神经保护功能扩展到了高血压大鼠模型的海马体。