Abstract：
Recently, we characterized the ferroptotic phenotype in the liver of diabetic mice and revealed nuclear factor (erythroid-derived-2)-related factor 2 (Nrf2) inactivation as an integral part of hepatic injury. Here, we aim to investigate whether sulforaphane, an Nrf2 activator and antioxidant, prevents diabetes-induced hepatic ferroptosis and the mechanisms involved. Male C57BL/6 mice were divided into four groups: control (vehicle-treated), diabetic (streptozotocin-induced; 40 mg/kg, from Days 1 to 5), diabetic sulforaphane-treated (2.5 mg/kg from Days 1 to 42) and non-diabetic sulforaphane-treated group (2.5 mg/kg from Days 1 to 42). Results showed that diabetes-induced inactivation of Nrf2 and decreased expression of its downstream antiferroptotic molecules critical for antioxidative defense (catalase, superoxide dismutases, thioredoxin reductase), iron metabolism (ferritin heavy chain (FTH1), ferroportin 1), glutathione (GSH) synthesis (cystine-glutamate antiporter system, cystathionase, glutamate-cysteine ligase catalitic subunit, glutamate-cysteine ligase modifier subunit, glutathione synthetase), and GSH recycling - glutathione reductase (GR) were reversed/increased by sulforaphane treatment. In addition, we found that the ferroptotic phenotype in diabetic liver is associated with increased ferritinophagy and decreased FTH1 immunopositivity. The antiferroptotic effect of sulforaphane was further evidenced through the increased level of GSH, decreased accumulation of labile iron and lipid peroxides (4-hydroxy-2-nonenal, lipofuscin), decreased ferritinophagy and liver damage (decreased fibrosis, alanine aminotransferase, and aspartate aminotransferase). Finally, diabetes-induced increase in serum glucose and triglyceride level was significantly reduced by sulforaphane. Regardless of the fact that this study is limited by the use of one model of experimentally induced diabetes, the results obtained demonstrate for the first time that sulforaphane prevents diabetes-induced hepatic ferroptosis in vivo through the activation of Nrf2 signaling pathways. This nominates sulforaphane as a promising phytopharmaceutical for the prevention/alleviation of ferroptosis in diabetes-related pathologies.
摘要：
最近,我们对糖尿病小鼠肝脏中的铁变性表型进行了表征，并揭示了核因子（红系衍生的2）相关因子2（Nrf2）失活是肝损伤的组成部分。这里,我们的目的是调查萝卜硫素，Nrf2活化剂和抗氧化剂，预防糖尿病诱导的肝脏铁死亡及其相关机制。将雄性C57BL/6小鼠分为四组：对照组（载体处理），糖尿病（链脲佐菌素诱导的；40毫克/千克，从第1天到第5天)，糖尿病萝卜硫素治疗组(第1天至第42天2.5mg/kg)和非糖尿病萝卜硫素治疗组(第1天至第42天2.5mg/kg)。结果表明，糖尿病诱导的Nrf2失活及其下游抗铁分子的表达降低，对抗氧化防御至关重要（过氧化氢酶，超氧化物歧化酶,硫氧还蛋白还原酶），铁代谢（铁蛋白重链（FTH1），铁蛋白1），谷胱甘肽（GSH）合成（胱氨酸-谷氨酸反转运系统，胱抑素,谷氨酸-半胱氨酸连接酶亚单位，谷氨酸-半胱氨酸连接酶修饰亚基，谷胱甘肽合成酶），GSH回收-谷胱甘肽还原酶（GR）被萝卜硫烷处理逆转/增加。此外,我们发现糖尿病肝脏的铁细胞表型与铁细胞吞噬增加和FTH1免疫阳性降低相关.通过GSH水平的增加进一步证明了萝卜硫烷的抗铁作用，不稳定铁和脂质过氧化物的积累减少（4-羟基-2-壬烯醛，脂褐素)，减少铁细胞吞噬和肝损伤(纤维化减少，丙氨酸氨基转移酶，和天冬氨酸氨基转移酶）。最后,萝卜硫烷显著降低了糖尿病诱导的血清葡萄糖和甘油三酯水平升高。尽管这项研究仅限于使用一种实验性糖尿病模型，获得的结果首次证明萝卜硫烷通过激活Nrf2信号通路在体内预防糖尿病诱导的肝铁蛋白死亡。这表明萝卜硫烷是一种有前途的植物药物，可用于预防/减轻糖尿病相关病理中铁死亡。
