肌肽对局灶性脑缺血大鼠外周血T淋巴细胞亚群的影响

目的:观察肌肽对局灶性脑缺血大鼠外周血中T淋巴细胞免疫功能的影响,探讨肌肽脑保护作用的免疫学机制?方法:将36只雄性SD大鼠随机分成假手术组(12只)?模型组(12只)和肌肽组(12只)?模型组和肌肽组以线栓法建立大鼠右侧大脑中动脉缺血模型,肌肽组于造模后按体质量1 g/(kg?d)予肌肽水溶液灌胃,其他两组予等量生理盐水灌胃?分别于造模后清醒时?缺血后24?72 h采用Longa评分法进行神经功能评分,于缺血后24?72 h流式细胞仪测定外周血T细胞亚群(CD3+?CD4+?CD8+)水平,并计算CD4+/CD8+值;于缺血后72 h用TTC染色测量脑梗死体积?结果:模型组与肌肽组均可见大脑中动脉供血区梗死灶,肌肽组梗死灶较模型组缩小(P < 0.05);造模后清醒时?缺血后24 h的肌肽组神经功能缺损评分与模型组比较无差异(P > 0.05),缺血后72 h肌肽组神经功能缺损评分较模型组降低(P < 0.05);缺血后24?72 h,模型组外周血CD3+?CD4+及CD4+/CD8+值明显低于假手术组(P < 0.05),CD8+水平明显高于假手术组(P < 0.05),缺血后72 h肌肽组CD8+水平明显低于模型组(P < 0.05)?结论:肌肽对脑缺血大鼠外周免疫抑制有调节作用,其机制可能与升高CD3+水平?CD4+/CD8+值和降低CD8+水平有关?

Effects of carnosine on T-lymphocyte immunity in peripheral blood of rats with focal cerebral ischemia

Objective:To explore effects of carnosine on peripheral blood T-lymphocyte immunity in MCAO rats and the neuroprotective mechanisms. Methods: Thirty-six male SD rats were randomly divided into three groups: the sham-operated group (n=12), the model group (n=12), and the carnosine-treated group (n=12). The middle cerebral artery occlusion model was established by suture method in the model group and the carnosine-treated group. After establishment of MCAO model, the rats in the carnosine-treated group were lavaged with soluble canosine once a day at the dose of 1 000 mg/kg, and the same volume of normal saline was lavaged in the sham operation and model group. The neurological function was scored with Longa 5-point scale at baseline, 24 h and 72 h. The level of peripheral blood T-lymphocyte subset (CD3+, CD4+, CD8+) was detected by flow cytometry at 24 and 72 h, and calculate CD3+/CD8+ ratio. The infarction volume was revealed by TTC stain at 72 h. Results: The infarction volumn was detected in both of the model group and the camosine-treated group. Compared with the model group, the infarction volume was smaller (P < 0.05); Compared with the model group, there was no significant different in the neurological outcome scores in the carnosine-treated group at baseline and 24 h (P > 0.05); however, there was a significant decrease at 72 h of the carnosine-treated group (P < 0.05); Compared with the sham-operated group, the level of CD3+, CD4+ and the CD4+/CD8+ ratio was significant decreased (P < 0.05) and the level of CD8+ was increased in the model group at 24 and 72 h (P < 0.05). Compared with the model group, the level of CD8+ was significant decreased in the carnosine-treated group at 72 h (P < 0.05). Conclusions: Carnosine could has potential protective effective on peripheral immune suppression of MCAO rats and the mechanism could be CD3+, CD4+/CD8+ elevation and CD8+ inhibition.