人工合成E-选择素对大鼠局灶性脑缺血再灌注损伤后脑组织一氧化氮合酶表达的影响

The Effects of Synthetic E-selectin on Nitric Oxide Synthase Expression in Brain of Rats with Focal Cerebral Ischemia Reperfusion Injury

目的探讨人工合成E-选择素对大鼠局灶性脑缺血/再灌注(I/R)损伤后脑组织一氧化氮合酶(NOS)及血清一氧化氮(NO)含量的影响。方法采用改良的Zea Longa法建立脑I/R损伤模型。66只雄性SD大鼠随机分为对照组、模型组和人工合成E-选择素治疗组(治疗组)。治疗组大鼠采用股静脉注射人工合成E-选择素10 mg·kg-1。应用硝酸盐还原法测定血清中NO含量和免疫组化法检测缺血区脑组织神经型一氧化氮合酶(nNOS)、诱导型一氧化氮合酶(iNOS)阳性细胞数。结果①NO:以对照组NO含量为正常生理数据,模型组脑缺血2 h/再灌注2~24 h NO含量呈上升趋势,24 h时达高峰,72 h有所降低但仍高于对照组,各时间点与对照组比较明显增高(P<0.01);治疗组NO变化趋势同模型组,NO含量较模型组减少(P<0.05),较对照组增多(P<0.01)。②NOS:以对照组nNOS、iNOS阳性细胞数为正常生理数据,模型组nNOS阳性细胞在脑缺血2 h/再灌注2 h后开始表达,12 h达高峰,至24 h开始降低,各时间点与对照组比较明显增高(P<0.01);模型组iNOS阳性细胞在脑缺血2 h/再灌注2 h开始出现,并持续增多,随时间延长呈上升趋势,24h达高峰,至72 h出现下降,各时间点与对照组比较明显增多(P<0.01);治疗组各时间点nNOS、iNOS阳性细胞变化趋势同模型组,但较模型组减少(P<0.05),较对照组增多(P<0.01)。结论大鼠脑I/R损伤后脑组织NOS活性表达增多,NO浓度升高导致脑组织损伤;人工合成E-选择素通过降低NOS表达,减少NO释放、减轻炎症反应和脑I/R损伤,起脑保护作用。

Aim To investigate the effects of synthetic E-selectin on nitric oxide synthase(NOS) and plasma nitric oxide(NO) in brain of rats with focal cerebral ischemia reperfusion injury. Methods SD rats with focal cerebral ischemia reperfusion injury model were established by Zea Longa suture method improved, 66 male SD rats were randomly divided into a control group, a model group and a treatment group with artificial synthesis of E-selectin. Serum nitric oxide content was determined. Neuronal nitric oxide synthase(nNOS) and inducible nitric oxide synthase(iNOS) positive cell number in cerebral ischemic region were analyzed with immunohistochemistry. Results ① There was no significant change of NO in the control group. In the model group, the NO content in serum of perfusion 2 h was higher than that of the control group. The content of NO interval 2 h^24 h increased, and reached a peak at 24 h, decreased at 72 h, but still higher than that of the control group at each time point. Compared with the control group, there was a significant increase(P<0.01). The change trend of the content of serum NO in the treatment group was in accord with that of the model group. The content of serum NO in the treatment group was less than that of the model group(P<0.05), and more than that of the control group(P<0.01). ② There was no significant change of NOS in the control group. In the model group, the number of nNOS positive cells began to express at 2 h after reperfusion, reached a peak at 12 h, and began to decrease after 24 h. At each time point, compared with the control group, the number of nNOS positive cells increased significantly(P<0.01). The number of iNOS positive cells appeared at 2 h after reperfusion, and continued to increase, reached a peak at 24 h, began to decrease after 72 h. At each time point, compared with the control group, the number of iNOS positive cells increased significantly(P<0.01). At each time point, the change trend of the number of nNOS and iNOS positive cells in the treatment group were accord with that of the model group. But the number of nNOS and iNOS positive cells in the treatment group were less than that of the model group(P<0.05), and more than that of the control group(P<0.01). Conclusion Brain NOS activity increased in rats with cerebral ischemia reperfusion injury. Because the release of high concentrations of NO led to brain tissue injury. Artificial synthetic E-selectin can protect brain through reducing the expression of NOS, decreasing the release of NO, relieving inflammatory reaction and cerebral ischemic reperfusion damage.