Departamento de Sistemas Biológicos, Universidad Autónoma Metropolitana Unidad Xochimilco Ciudad de México, Mexico.
Departamento de Neuroquímica, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez, Ciudad de México, Mexico.
Oxid Med Cell Longev. 2018 Nov 5;2018:3265918. doi: 10.1155/2018/3265918. eCollection 2018.
After spinal cord injury (SCI), some self-destructive mechanisms start leading to irreversible neurological deficits. It is known that oxidative stress and apoptosis play a major role in increasing damage after SCI. Metallothioneins I and II (MT) are endogenous peptides with known antioxidant, neuroprotective capacities. Taking advantage of those capacities, we administered exogenous MT to rats after SCI in order to evaluate the protective effects of MT on the production of reactive oxygen species (ROS) and lipid peroxidation (LP), as markers of oxidative stress. The activities of caspases-9 and -3 and the number of annexin V and TUNEL-positive cells in the spinal cord tissue were also measured as markers of apoptosis. Rats were subjected to either sham surgery or SCI and received vehicle or two doses of MT (10 g per rat) at 2 and 8 h after surgical procedure. The results showed a significant increase in levels of MT protein by effect of SCI and SCI plus treatment at 12 h, while at 24 h an increase of MT was observed only in the injury plus treatment group ( < 0.05). ROS production was decreased by effect of MT in lesioned tissue; likewise, we observed diminished LP levels by MT effect both in the sham group and in the group with SCI. Also, the results showed an increase in the activity of caspase-9 due to SCI, without changes by effect of MT, as compared to the sham group. Caspase-3 activity was increased by SCI, and again, MT treatment reduced this effect only at 24 h after injury. Finally, the results of the number of cells positive to annexin V and TUNEL showed a reduction due to MT treatment both at 24 and 72 h after the injury. With the findings of this work, we conclude that exogenously administered MT has antioxidant and antiapoptotic effects after SCI.
脊髓损伤（SCI）后，一些自我破坏机制开始导致不可逆转的神经功能缺损。已知氧化应激和细胞凋亡在 SCI 后增加损伤中起主要作用。金属硫蛋白 I 和 II（MT）是具有已知抗氧化、神经保护能力的内源性肽。利用这些能力，我们在 SCI 后给大鼠施用外源性 MT，以评估 MT 对活性氧（ROS）和脂质过氧化（LP）产生的保护作用，作为氧化应激的标志物。还测量了脊髓组织中 caspase-9 和 -3 的活性以及膜联蛋白 V 和 TUNEL 阳性细胞的数量作为细胞凋亡的标志物。大鼠接受假手术或 SCI，并在手术后 2 和 8 小时接受载体或 MT（每只大鼠 10g）两次剂量。结果显示，SCI 后 MT 蛋白水平显著增加，12 小时后 SCI 加治疗组也观察到 MT 增加，而 24 小时后仅在损伤加治疗组观察到 MT 增加（<0.05）。MT 对损伤组织中的 ROS 产生有抑制作用；同样，我们观察到 MT 对 sham 组和 SCI 组的 LP 水平都有降低作用。此外，结果显示由于 SCI，caspase-9 的活性增加，而 MT 没有变化，与 sham 组相比。Caspase-3 活性因 SCI 而增加，而 MT 治疗仅在损伤后 24 小时降低了这种作用。最后，膜联蛋白 V 和 TUNEL 阳性细胞数的结果显示，MT 治疗在损伤后 24 和 72 小时均减少。根据这项工作的结果，我们得出结论，外源性给予 MT 后具有抗氧化和抗细胞凋亡作用。
