Zare Ali, Ghanbari Alireza, Hoseinpour Mohammad Javad, Eskandarian Boroujeni Mahdi, Alimohammadi Alimohammad, Abdollahifar Mohammad Amin, Aliaghaei Abbas, Mansouri Vahid, Arani Hamid Zaferani
Young Researchers and Elite Club, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran.
Department of Stem Cells and Regenerative Medicine, Faculty of Medical Biotechnology, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran.
Galen Med J. 2021 Feb 2;10:e2016. doi: 10.31661/gmj.v10i0.2016. eCollection 2021.
Methamphetamine (MA), is an extremely addictive stimulant that adversely affects the central nervous system. Accumulating evidence indicates that molecular mechanisms such as oxidative stress, apoptosis, and autophagy are involved in the toxicity of MA. Considering experimental animal studies exhibiting MA-induced neurotoxicity, the relevance of these findings needs to be evidently elucidated in human MA users. It is generally assumed that multiple chemical substances released in the brain following MA-induced metabolic activation are primary factors underlying damage of neural cells. Hence, this study aimed to investigate the role of autophagy and apoptosis as well as oxidative stress in the brain of postmortem MA-induced toxicity.
In this study, we determine the gene expression of autophagy and apoptosis, including BECN1, MAP1ALC3, CASP8, TP53, and BAX genes in ten healthy controls and ten chronic users of MA postmortem dorsolateral prefrontal cortex (DLPFC) by real-time polymerase chain reaction. Also, we applied immunohistochemistry in formalin-fixed and paraffin-embedded human brain samples to analyze brain-derived neurotrophic factor (BDNF). Also, spectrophotometry was performed to measure glutathione (GSH) content.
The expression level of apoptotic and autophagic genes (BECN1, MAP1ALC3, CASP8, TP53, and BAX) were significantly elevated, while GSH content and BDNF showed substantial reductions in DLPFC of chronic MA users. Discussion: Our data showed that MA addiction provokes transduction pathways, namely apoptosis and autophagy, along with oxidative mechanisms in DLPFC. Also, MA induces multiple functional and structural perturbations in the brain, determining its toxicity and possibly contributing to neurotoxicity.
Our study showed BDNF-positive cells as well as GSH amount, displayed significant declines in DLPFC of MA user. MA addiction provokes transduction pathways, namely apoptosis and autophagy, along with oxidative mechanisms in DLPFC. However, further investigations are needed to throw light on the cellular and molecular mechanisms that act in the various regions of the addicted brain, especially in DLPFC.
甲基苯丙胺（MA）是一种极易成瘾的兴奋剂，会对中枢神经系统产生不利影响。越来越多的证据表明，氧化应激、细胞凋亡和自噬等分子机制与MA的毒性有关。考虑到实验动物研究显示出MA诱导的神经毒性，这些发现与人类MA使用者的相关性需要得到明确阐明。一般认为，MA诱导的代谢激活后在大脑中释放的多种化学物质是神经细胞损伤的主要因素。因此，本研究旨在探讨自噬、细胞凋亡以及氧化应激在MA诱导的死后毒性大脑中的作用。
在本研究中，我们通过实时聚合酶链反应测定了10名健康对照者和10名MA慢性使用者死后背外侧前额叶皮质（DLPFC）中自噬和凋亡相关基因的表达，包括BECN1、MAP1ALC3、CASP8、TP53和BAX基因。此外，我们在福尔马林固定、石蜡包埋的人脑样本中应用免疫组织化学分析脑源性神经营养因子（BDNF）。同时，采用分光光度法测量谷胱甘肽（GSH）含量。
慢性MA使用者的DLPFC中凋亡和自噬基因（BECN1、MAP1ALC3、CASP8、TP53和BAX）的表达水平显著升高，而GSH含量和BDNF则显著降低。讨论：我们的数据表明，MA成瘾会引发转导通路，即细胞凋亡和自噬，以及DLPFC中的氧化机制。此外，MA会在大脑中诱导多种功能和结构紊乱，决定其毒性，并可能导致神经毒性。
我们的研究表明，MA使用者的DLPFC中BDNF阳性细胞以及GSH含量显著下降。MA成瘾会引发转导通路，即细胞凋亡和自噬，以及DLPFC中的氧化机制。然而，需要进一步研究以阐明在成瘾大脑的各个区域，特别是DLPFC中起作用的细胞和分子机制。
