牛磺酸对重型颅脑创伤大鼠线粒体呼吸链酶活性的影响

Effect of taurine on respiratory chain enzyme activities in mitochondria from rats with severe traumatic brain injury

目的 研究牛磺酸对重型颅脑创伤大鼠伤后24h脑线粒体呼吸链酶活性的影响及保护作用.方法 56只SD雄性大鼠按随机数字表法分为假手术组、颅脑创伤组、牛磺酸治疗组、牛磺酸预防组,每组14只.液压冲击制作颅脑创伤模型,尾静脉给药（前两组伤后即刻给予等渗盐水,牛磺酸治疗组给予牛磺酸,牛磺酸预防组伤前4d每天给予牛磺酸,剂量200 mg/ml）.于24 h后处死取脑组织,行常规HE染色、透射电镜观察脑超微结构;检测线粒体呼吸链酶复合物Ⅰ、Ⅱ、Ⅳ、Ⅴ的活性.结果 （1）HE染色：颅脑创伤组神经细胞肿胀、细胞丢失、细胞核固缩、突起短小消失,坏死灶边缘可见炎性细胞浸润.与颅脑创伤组比较,牛磺酸治疗组形态上有显著改善,牛磺酸预防组仅部分神经元较完整.（2）电镜：与假手术组比较,颅脑创伤组线粒体肿胀畸形、嵴断裂或消失;而牛磺酸治疗组线粒体正常或轻度肿胀;牛磺酸预防组细胞质稍疏松,线粒体嵴部分断裂.（3）呼吸链酶：颅脑创伤组线粒体呼吸链酶复合物Ⅰ、Ⅱ、Ⅴ活性较假手术组显著下降（32.52±2.41∶34.03 ±0.46,4.68 ±0.15∶5.04 ±0.29,2.49 ±0.73∶3.20 ±0.68,P均＜0.05）;与颅脑创伤组比较,牛磺酸治疗组线粒体呼吸链复合物Ⅰ （33.95 ±0.85）、Ⅱ（5.12 ±0.23）、Ⅴ（3.53 ±0.48）及牛磺酸预防组复合物Ⅰ （34.44±0.36）活性均有明显升高（P＜0.05）.结论 外源性牛磺酸均对颅脑创伤大鼠早期脑组织及线粒体结构具有一定保护作用,其机制可能与提高脑组织线粒体呼吸链酶活性和减少继发能量损失有关.

Objective To investigate effect of taurine on respiration chain enzyme activity of mitochondria 24 hours after severe traumatic brain injury （TBI） in rats.Methods Fifty-six SD rats were divided into sham group,TBI group,taurine treatment group,and taurine prevention group according to the random number table,with 14 rats per group.Fluid percussion brain injury models were used.Via the caudal vein,normal saline was administered to animals in sham and traumatic brain injury groups immediately after injury,while taurine （200 mg/kg）was administered to animals in taurine treatment group after injury and in taurine prevention group 4 days before injury.Brains were harvested 24 hours postinjury for assays of HE staining and electron microscopy.Mitochondrial respiratory chain complex Ⅰ-Ⅴ activities were detected.Results TBI group presented swelling neurocytes,cell loss,karyopyknosis,shortened even vanished process,and inflammation cell infiltration at the edge of necrosis in HE staining.By contrast,morphological improvement was significant in taurine treatment group but only some neurons were intact in taurine prevention group.Swelling mitochondria and broken or vanished mitochondrial crests were seen in TBI group under the electron microscope.However,normal or minor swelling mitochondria was seen in taurine treatment group and cytoplasm slightly porous and absence of mitochondrial crests were seen in taurine prevention group.Activities of complex Ⅰ,Ⅱ and Ⅴ were significant lower in TBI group （32.52±2.41,4.68 ±0.15,2.49 ±0.73） compared to those in sham group （34.03 ±0.46,5.04 ±0.29,3.20±0.68） and in taurine treatment group （33.95±0.85,5.12-±0.23,3.53 ±0.48） （P〈0.05）.And complex Ⅰ in taurine prevention group was significantly enhanced as well （34.44 ± 0.36,P 〈 0.05）.Conclusion Taurine may protect the brain tissues and mitochondrial structure from impairment in TBI rats by improving mitochondrial enzymes activity and reducing secondary energy loss.