Dursun Erdinç, Gezen-Ak Duygu, Yilmazer Selma
Department of Medical Biology, İstanbul University Cerrahpaşa Faculty of Medicine, İstanbul, Turkey.
Noro Psikiyatr Ars. 2014 Jun;51(2):163-168. doi: 10.4274/npa.y7089. Epub 2014 Jun 1.
Neurodegeneration is a process that is characterized by the loss of neuronal structure and function and eventually ends with neuronal death. An elevated level of inducible nitric oxide synthase (iNOS) is suggested to accompany this process by inducing oxidative and nitrosative damage. Vitamin D is reported to protect glial cells against neurotoxicity via suppressing iNOS synthesis. Though there was no data about whether iNOS is regulated by vitamin D in hippocampal neurons. In this study our aim was to determine any alteration in iNOS expression of hippocampal neurons in response to vitamin D treatment.
Twenty four and 48 hours of vitamin D treatments were performed on primary hippocampal neuron cultures that were prepared from Sprague dawley rat embryos (E18). The alterations in the iNOS mRNA expression were determined with quantative real time polymerase chain reaction (qRT-PCR). The cytotoxicity levels of each group were investigated by the measurement of lactate dehydrogenase (LDH) that is released to culture medium.
No difference was observed between groups in 24 hours of treatment regarding the iNOS expression. Though the iNOS mRNA level of vitamin D treated group was significantly lower than that of control group on the 48th hours of treatment (p<.001). Vitamin D treatment also attenuated the LDH release which is an indicator of cytotoxicity (p<.001).
Our results indicated that vitamin D has the potential to prevent oxidative damage by suppressing iNOS expression.
神经退行性变是一个以神经元结构和功能丧失为特征的过程，最终以神经元死亡告终。诱导型一氧化氮合酶（iNOS）水平升高被认为通过诱导氧化和亚硝化损伤而伴随这一过程。据报道，维生素D通过抑制iNOS合成来保护神经胶质细胞免受神经毒性。尽管尚无关于海马神经元中iNOS是否受维生素D调节的数据。在本研究中，我们的目的是确定维生素D处理后海马神经元iNOS表达的任何变化。
对从Sprague dawley大鼠胚胎（E18）制备的原代海马神经元培养物进行24小时和48小时的维生素D处理。用定量实时聚合酶链反应（qRT-PCR）测定iNOS mRNA表达的变化。通过测量释放到培养基中的乳酸脱氢酶（LDH）来研究每组的细胞毒性水平。
在24小时处理时，各组之间在iNOS表达方面未观察到差异。尽管在处理的第48小时，维生素D处理组的iNOS mRNA水平显著低于对照组（p<0.001）。维生素D处理还减弱了作为细胞毒性指标的LDH释放（p<0.001）。
我们的结果表明，维生素D具有通过抑制iNOS表达来预防氧化损伤的潜力。
