颅脑损伤合并海水浸泡对大鼠脑线粒体的研究及意义

Mitochondria of damaged brain tissues following traumatic brain injury and immersion in rat models

目的为研究海战伤中脑损伤的病理机制,检测海水浸泡对伤后不同时间点脑皮质组织中线粒体功能。方法雄性SD大鼠55只,随机分为假手术组(n=5)、创伤性脑损伤(TBI)组(n=25)、TBI+海水组(n=25),两损伤组按伤后不同时间点(6 h、12 h、1 d、3 d、5 d)再分5个亚组。采用尼氏染色观察神经细胞损伤;凋亡染色观察神经细胞凋亡;检测线粒体膜电位(MMP)、H+-ATPase活性、三磷酸腺苷(ATP)含量以及线粒体丙酮酸脱氢酶(PDH)、还原型辅酶Ⅰ(NADH)、琥珀酸脱氢酶(SDH)活性,观察海水浸泡后脑皮质组织中线粒体功能的变化。结果 TBI组结果显示3 d时损伤最重;TBI+海水组在伤后个时间点的结果均低于TBI组且1 d时神经细胞损伤最重、凋亡细胞最多、线粒体功能最低(P<0.05)。结论海水浸泡在撞击创伤基础上加重了对脑组织的损伤,使得短时间内损伤更严重。这也给今后海战伤脑保护的机制研究提供了一定的实验基础,对脑损伤者进行有效的保护至关重要。

Objective The mild and moderate traumatic brain injury （TBI） model with seawater immersion was set up and the pathogenesis of seawater on mitochondria of damaged brain tissues was investigated.Methods Fifty-five adult Sprague-Dawley （SD） rats were used in the study and divided into sham group （n=5）, TBI group （n=25）, and TBI ＋seawater group （n=25）, respectively.TBI was produced by a modified weight-drop model.TBI and TBI ＋seawater were divided into five subgroups according to different time points after injury （6 h, 12 h, 1 d, 3 d, 5 d ）.The damage of neuron was observed by Nepalˊs staining.Apoptosis was observed by terminal dexynucleotidyl transferase （TdT）-mediated 2ˊ-Deoxyuridine 5ˊ-Triphosphate （dUTP） Nick-End labeling （TUNEL）. Mitochondrial membrane potential （MMP）, H＋-ATPase activity and adenosine triphosphate （ATP） content were measured by multifunctional enzyme-labeled instrument.Pyruvate dehydrogenase （PDH）, succinate dehydrogenase （SDH） and nicotinamide adenine dinucleotide （NADH） activity were measured by microplate reader.Results TBI group showed that the injury in brain tissues was the most severe at 3 d.In TBI＋seawater group the injury in brain tissues was the most severe at 1 d and the mitochondrial function was worse than that of TBI group at different time points （P〈0.05）.Conclusion Seawater can promote neuronal apoptosis and aggravate brain damage in a short period.These could provide the experimental basis for mechanism of brain protection after seawater immersion.