消脱止-M对创伤性脑损伤后脑部微循环和神经功能的保护作用

The protective effects of melilotus extract tablet on neurological function and cerebral microcirculation after traumatic brain injury in rats

目的探讨消脱止-M对创伤性脑损伤（TBI）脑部微循环的保护作用及神经功能的影响。方法将52只雄性sD大鼠按随机数字表法分为假手术组（n=12）、TBI组（n=20）和消脱止-M组（n=20）。采用动物液压冲击仪（2．0arm，1arm=101．325kPa）建立大鼠TBI模型，消脱止-M组灌胃消脱止-M30ms／ks，假手术组和TBI组灌胃等量生理盐水，均连用7d。扫描电镜下观察大鼠脑部微循环结构的改变。术后1、3、7d采用实时定量-聚合酶链反应（RT—PCR）检测TBI后脑部炎症细胞因子肿瘤坏死因子-α（TNF—Of）及核转录因子-KB（NF—KB）基因表达；采用黄嘌呤氧化酶法测定脑组织与血清中超氧化物歧化酶（SOD）活性。TBI后7d和14d采用神经系统疾病严重程度评分（NSS）评价大鼠神经功能的改善状况。结果TBI组大鼠脑血管水肿、神经元胞质和细胞器肿胀、溶解、消失，以及外周神经毡肿胀、电子密度降低；消脱止-M组给药7d后脑血管水肿和神经元细胞肿胀较TBI组有所缓解，电子密度也有所增加。与假手术组比较，TBI组和消脱止-M组脑组织TNF—d和NF—xB基因表达水平明显上升，SOD活性明显下降（均P〈0．05）；与TBI组比较，消脱止-M组大鼠脑部微循环明显改善，给药后1d消脱止-M组TNF-α、NF—KB基因表达水平即明显降低（TNF-α：1．483±0．062比2．231±0．051；NF—KB：1．692±0．063比2．250±0．059，均P〈0．05），血清与脑组织SOD（U／mg）活性即明显升高（血清：213．37±12．02比190．12±6．73，脑组织：211．56±11．14比163．22±14．32，均P〈O．05），给药后7dNSS（分）即明显降低（8．10±0．35比9．30±0．53，P〈0．05）。结论消脱止-M对大鼠TBI后的微循环结构有明显保护作用，且可促进神经功能的修复，其作用机制可能与炎症因子TNF-a、NF—KB基因表达下降及SOD上升相关。

Objective To explore the protective effects of melilotus extract tablet （MET） on cerebral microcirculation and neurological function after traumatic brain injury （TBI） in rats. Methods Fifty-two male SD rats were randomly divided into sham operation （n= 12）, TBI （n=20） and MET groups （n=20）. The rat＇s TBI model was reproduced with fluid percussion （2.0 atm, 1 atm = 101.325 kPa）. After the establishment of TBI model, the rats in MET group were treated with MET （30 mg/kg） by gavage, while rats in sham operation and TBI groups were given the gavage of equal amount of normal saline for consecutive 7 days. The structure of rat cerebral microcirculation was observed by scanning electron microscope （SEM）. On 1,3 and 7 days after TBI, the mRNA expressions of tumor necrosis factor-ct （TNF-ct ） and nuclear factor-KB （NF-KB） in the brain were measured by real-time polymerase chain reaction （RT-PCR）, and the activities of superoxide dismutase （SOD） in rat brain and serum were determined by xanthine oxidase method. The improvement of neurological function was evaluated by the modified neurological severity score （NSS） on the 7th and 14th day after TBI. Results The cerebral edema, the swelling of neuronal cytoplasm and organelles with their disappearance and dissolution, distension of peripheral neuropil and low density of the pathological area were more obvious in TBI group. Seven days later, the cerebral edema and neuronal swelling in MET group were milder than those in TBI group, and the electron density in the former group was also higher. Compared with sham operation group, the expressions of TNF- c~ and NF-KB mRNA were significantly higher, whereas SOD level was markedly lower in TBI and MET groups （all P〈0.05）. Compared with TBI group, the improvement in cerebral microcirculation in MET group was obvious, one day after TBI, the expressions of mRNA TNF- c~ and NF-gB were lowered significantly （TNF-a ： 1.483＋0.062 vs. 2.231＋0.051 ; NF-KB ： 1.692＋0.063 vs. 2.250＋0.059, all P〈0.05）, while the SOD （U/mg）levels in serum and brain were remarkably increased （serum ：213.37 ＋ 12.02 vs. 190.12＋6.73 ; brain ： 211.56＋ 11.14 vs. 163.22＋ 14.32, both P 〈 0.05）, and NSS score was much lower after 7 days＇ treatment in the MET group （8.10＋0.35 vs. 9.30＋0.53, P〈0.05）. Conclusion It is shown that MET has an obvious protective effect on structure of cerebral microcirculation and can improve neurological function after TB! in rat brain, and the mechanism is possibly related to the down-regulation of mRNA TNF- a and NF-KB and up-regulation of SOD.