羧甲基化灵芝多糖预处理对大鼠脑缺血再灌注损伤的影响及其机制

Influence of carboxymethylated ganoderma lucidum polysaccharide pretreatment on cerebral ischemia-reperfusion injury in rats

目的探讨羧甲基化灵芝多糖(CM-GLP)预处理对大鼠脑缺血再灌注损伤的影响及其可能的作用机制。方法将100只SD大鼠随机分为假手术组、模型组、灵芝多糖(GLP)组、CM-GLP组、尼莫地平组,每组20只。GLP组腹腔注射GLP 40 mg/(kg·d),CM-GLP组腹腔注射CM-GLP 40 mg/(kg·d),尼莫地平组腹腔注射尼莫地平1 mg/(kg·d),假手术组和模型组腹腔注射等体积生理盐水。各组用药均为1次/d,连续注射7 d。除假手术组外,其余各组均建立脑缺血再灌注模型。各组脑缺血再灌注24 h行神经功能缺损评分,处死后采用干湿法检测脑组织含水量,采用ELISA法检测脑组织超氧化物歧化酶(SOD)活性、丙二醛(MDA)表达以及NF-κB、TNF-α、IL-1、IL-6表达,采用Western blotting法检测脑组织热休克蛋白70(HSP70)、磷酸化丝氨酸/苏氨酸蛋白激酶(p-Akt)蛋白表达。结果模型组神经功能评分高于假手术组,GLP组、CM-GLP组及尼莫地平组均低于模型组,且CM-GLP组及尼莫地平组较模型组降低更明显(P均<0.01)。模型组脑组织含水量、MDA表达及NF-κB、TNF-α、IL-1、IL-6表达均高于假手术组,SOD活性及HSP-70、p-Akt蛋白相对表达量均低于假手术组(P均<0.01)。GLP组、CM-GLP组、尼莫地平组脑组织含水量、MDA、NF-κB、TNF-α、IL-1、IL-6表达均低于模型组,SOD活性及HSP-70、p-Akt蛋白相对表达量均高于模型组,且CM-GLP组及尼莫地平组变化更明显(P<0.05或<0.01)。结论 CM-GLP预处理可减轻大鼠脑缺血再灌注损伤;其机制可能与调控HSP70/PI3K/Akt信号通路、减轻再灌注后继发的炎症反应有关。

Objective To observe the influefice of earboxymethylated ganoderma lueidum polysaecharide （CM-GLP） pretreatment on the cerebral ischemia-reperfusion injury in rats and its possible mechanism. Methods Totally 100 SD rats were randomly divided into five groups： the sham group, the model group, the GLP group, the CM-GLP group, and the ni- modipine group, with 20 in each. The GLP group received intraperitoneal injection of GLP 40 mg/（ kg · d）, the CM-GLP group received CM-GLP of 40 rag/（ kg · d）, the nimodipine group received nimodiping of 1 rag/（ kg · d）, and the sham group and the model group both received the same volulne of normal saline. The rat cerebral ischemia reperfusion model was established by the middle cerebral artery occlusion method in rats of all groups except for the sham group. At 24 h ＇after ischemia-reperfusion, the neurologic deficit score was detected as well as the content of water in brain tissues. The expression of superoxide dismutase （SOD） and malondialdehyde （MDA）, the levels ofNF-κB, TNF-α, IL-1, and IL-6 in the brain tissues were detected by ELISA. Western blotting was used to detect the protein expression levels of heat shock protein-70 （HSP-70） and p-Akt. Results The neurologic deficit score of the model group was significantly higher than that of the sham group, and the GLP group, the CM-GLP group, and the nimodipine group were lower than the model group, further more, the CM-GLP group and the nimodipine group decreased more significantly （P 〈 0.01 ）. The content of water in the brain tissues of the rats, the levels of MDA and the levels of NF-KB, TNF-α, IL-1, and IL-6 of the model group were high er than those of the sham group, while the SOD activity and the protein expression of p-Akt and the HSP-70 were lower than those of the sham group （ all P 〈 0.01 ）. The content of water in the brain tissues of the rats, the levels of MDA and the levels of NF-KB, TNF-α, IL-1, and IL-6 of the GLP group, the CM-GLP group, and the nimodipine group were lower than those of the model group, while the SOD activity, the protein expression of p-Akt, and the HSP-70 were higher than those of the mod- el group, furthermore the CM-GLP group and the nimodipine group changed more significantly （ P 〈 O. 05 or P 〈 0.01 ）. Conclusion CM-GLP pretreatment can effectively relieve the cerebral ischemia-reperfusion injury in rats by regulating the HSPTO/PI3K/Akt signaling pathway and inhibiting the inflanunatory reaction damage to the nerve cells after reperfusion.