Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand; Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand.
Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand.
Life Sci. 2019 Dec 15;239:116878. doi: 10.1016/j.lfs.2019.116878. Epub 2019 Oct 31.
We previously demonstrated that iron-overload in non-thalassemic rats induced neurotoxicity and cognitive decline. However, the effect of iron-overload on the brain of thalassemic condition has never been investigated. An iron chelator (deferiprone) provides neuroprotective effects against metal toxicity. Furthermore, a T-type calcium channels blocker (efonidipine) effectively attenuates cardiac dysfunction in thalassemic mice with iron-overload. However, the effects of both drugs on brain of iron-overload thalassemia has not been determined. We hypothesize that iron-overload induces neurotoxicity in Thalassemic and wild-type mice, and not only deferiprone, but also efonidipine, provides neuroprotection against iron-overload condition.
Mice from both wild-type (WT) and β-thalassemic type (HT) groups were assigned to be fed with a standard-diet or high-iron diet containing 0.2% ferrocene/kg of diet (HFe) for 4 months consecutively. After three months of HFe, 75-mg/kg/d deferiprone or 4-mg/kg/d efonidipine were administered to the HFe-fed WT and HT mice for 1 month.
HFe consumption caused an equal impact on circulating iron-overload, oxidative stress, and inflammation in WT and HT mice. Brain iron-overload and iron-mediated neurotoxicity, such as oxidative stress, inflammation, glial activation, mitochondrial dysfunction, and Alzheimer's like pathologies, were observed to an equal degree in HFe fed WT and HT mice. These pathological conditions were mitigated by both deferiprone and efonidipine.
These findings indicate that iron-overload itself caused neurotoxicity, and T-type calcium channels may play a role in this condition.
我们之前的研究表明,非地中海贫血症大鼠的铁过载会导致神经毒性和认知功能下降。然而,铁过载对地中海贫血症患者大脑的影响尚未得到研究。一种铁螯合剂(地拉罗司)具有对抗金属毒性的神经保护作用。此外,T 型钙通道阻滞剂(依福地平)可有效减轻铁过载地中海贫血症小鼠的心脏功能障碍。然而,这两种药物对铁过载地中海贫血症患者大脑的影响尚未确定。我们假设铁过载会导致地中海贫血症和野生型小鼠的神经毒性,不仅地拉罗司,而且依福地平也能提供针对铁过载状态的神经保护作用。
将来自野生型(WT)和β地中海贫血型(HT)的两组小鼠分别喂食标准饮食或含有 0.2%二茂铁/千克饮食的高铁饮食(HFe),连续 4 个月。在 HFe 喂养 3 个月后,75mg/kg/d 的地拉罗司或 4mg/kg/d 的依福地平分别给予 HFe 喂养的 WT 和 HT 小鼠 1 个月。
HFe 的摄入对 WT 和 HT 小鼠的循环铁过载、氧化应激和炎症产生了同等的影响。在 HFe 喂养的 WT 和 HT 小鼠中观察到脑铁过载和铁介导的神经毒性,如氧化应激、炎症、胶质细胞激活、线粒体功能障碍和阿尔茨海默病样病理,其程度相当。这两种病理状况都得到了地拉罗司和依福地平的缓解。
这些发现表明铁过载本身会导致神经毒性,而 T 型钙通道可能在这种情况下发挥作用。