丁苯酞对大鼠脑组织放射性损伤的保护作用

Protective effect of DL-3-n-Butylphthalide on radiation injury of rat brain tissue

目的探讨丁苯酞对大鼠单次全脑照射后的防护作用机制。方法120只SD大鼠采用随机数字法分为假照射组、照射组和丁苯酞组。采用10Gy单次全脑照射模型，制模后丁苯酞组大鼠分别按剂量0．3、1．0和3．0mg／kg丁苯酞腹腔注射；测定脑组织中丙二醛（MDA）含量和超氧化物歧化酶（SOD）活性，采用免疫组织化学法检测海马凋亡相关基因蛋白表达的变化，并在电镜下观察组织学超微结构。结果与假照射组比较，照射后大鼠脑组织中MDA含量升高、SOD活性降低，促凋亡基因bax表达增高（t=-3．78--1．89；2．69-3．48，P〈0．05）、抑凋亡基因bcl-2表达下降，电镜下照射组大鼠海马CAl区神经元呈明显的凋亡超微结构形态；与照射组比较，丁苯酞组大鼠脑组织中MDA含量降低、SOD活性升高，Bcl-2蛋白表达显著增加、Bax蛋白表达明显降低（t=2．94～3．76，-3．89～-1．96，P〈0．05），神经细胞结构损伤明显轻于照射组。结论丁苯酞通过降低大鼠全脑照射后脑组织中MDA含量、升高SOD活性，有效抑制凋亡，对放射性脑损伤的保护作用呈现剂量依赖性。

Objective To investigate the protective effect and its mechanism of DL-3-n- Butylphthalide on the brain damage in rats following whole brain irradiation. Methods A total of 120 male Sprague Dawley rats were randomly divided into sham-irradiation group, irradiation group and DL-3-n- Butylphthalide group. The model of whole-brain irradiation was established by exposuring rat brain to 4 MeV X-rays with a single-dose of 10 Gy. The rats were intraperitoneally injected with DL-3-n- Butylphthalide at the dosages of 0. 3, 1.0, and 3.0 mg/kg once a day. The contents of malondialdehyde and super oxide dismutase activity were measured, while the expressions of apoptosis-associated genes and the ultrastructural changes in hippocampus were examined by immunohistochemisty staining and electron microscope, respectively. Results After irradiation, the content of malondialdchyde and the expression of apoptosis gene bax in rat brain tissue increased while the activity of super oxide dismutase（SOD） and the expression of anti-apoptosis gene bcl-2 decreased. Apoptosis was also observed in the neurons of hippocampus CA1. Compared with irradiation group, the content of malondialdehyde and the expression of bax gene in the DL-3-n-Butylphthalide group were significantly reduced （ t = - 3.89 - - 1.96,2.72 - 3.48 ,P 〈 0.05 ） , while the activity of SOD and bcl-2 gene were significantly elevated （ t = 2. 94 - 3.76, -3. 18- -2.08, P 〈 0.05）, and the injury degree of neuron structure in the DL-3-n-Butylphthalide group was slighter than that in the irradiation group. Conclusions DL-3-n-Butylphthalide executes protective effects in a dose-dependent manner againest the radiation injury in rats brain by reducing the induction of malondialdehyde, raising the activity of SOD and inhibiting the generation of apoptosis.