Klotho蛋白灌胃对急性脑梗死大鼠脑缺血再灌注损伤的改善作用及其机制

Ameliorating effect of Klotho protein on cerebral ischemia-reperfusion injury in rats with acute cerebral infarction and its mechanism

目的观察Klotho蛋白灌胃对急性脑梗死(ACI)大鼠脑缺血再灌注损伤(CIRI)的改善作用,并探讨其作用机制。方法50只SPF级SD雄性大鼠分为假手术组、模型组、Klotho低剂量组、Klotho中剂量组、Klotho高剂量组,每组10只。模型组和Klotho低剂量组、Klotho中剂量组、Klotho高剂量组大鼠建立ACI后CIRI模型。假手术组只做颈动脉血管分离和伤口缝合,不做颈动脉夹闭处理。大鼠继续饲养24 h后,Klotho低、中、高剂量组分别用25、50、100 mg/kg的Klotho蛋白进行灌胃处理,模型组与假手术组均采用等体积生理盐水进行灌胃处理。5组大鼠均每天灌胃处理1次,持续处理14 d。取各组大鼠,采用Longa评分法和平衡木评分法进行神经功能评分。取各组大鼠,断头处死后取脑组织,采用苏木精染色法测算大鼠大脑皮层神经元凋亡率,采用Western Blotting法检测大鼠大脑皮层组织中受体相互作用蛋白激酶1(RIP1)、RIP3蛋白,采用酶联免疫法检测大鼠大脑皮层组织中炎症介质IL-1β、TNF-α、IL-6,采用TBA法检测MDA,采用酶联免疫法检测SOD,采用紫外比色法检测GSH-Px。结果假手术组大鼠神经功能评分、大脑皮层神经元凋亡率均低于其余各组(P均<0.05),模型组均高于其余各组(P均<0.05),Klotho高剂量组均高于Klotho低剂量组、Klotho中剂量组(P均<0.05),Klotho中剂量组均高于Klotho低剂量组(P均<0.05)。假手术组大鼠大脑皮层组织中RIP1、RIP3蛋白相对表达量和IL-1β、TNF-α、IL-6、MDA表达水平均低于其余各组,SOD、GSH-Px表达水平均高于其余各组(P均<0.05),模型组大鼠大脑皮层组织中RIP1、RIP3蛋白相对表达量和IL-1β、TNF-α、IL-6、MDA表达水平均高于其余各组,SOD、GSH-Px表达水平均低于其余各组(P均<0.05),Klotho高剂量组大鼠大脑皮层组织中RIP1、RIP3蛋白相对表达量和IL-1β、TNF-α、IL-6、MDA表达水平均低于Klotho低剂量组、Klotho中剂量组,SOD、GSH-Px表达水平均高于Klotho低剂量组、Klotho中剂量组(P均<0.05),Klotho中剂量组大鼠大脑皮层组织中RIP1、RIP3蛋白相对表达量和IL-1β、TNF-α、IL-6、MDA表达水平均低于Klotho低剂量组,SOD、GSH-Px表达水平均高于Klotho低剂量组(P均<0.05)。结论100 mg/kg Klotho蛋白灌胃对ACI大鼠CIRI具有改善作用,其作用机制可能与抑制大脑皮层组织中RIP1和RIP3蛋白表达、抑制脑损伤部位炎症反应和氧化应激反应有关。

Objective To observe the ameliorating effect of intragastric administration of Klotho protein on cerebral ischemia-reperfusion injury(CIRI)in rats with acute cerebral infarction(ACI)and to explore its mechanism.Methods Fifty SD male rats were divided into the sham operation group,model group,low-dose Klotho group,medium-dose Klotho group and high-dose Klotho group,with 10 rats in each group.CIRI models after ACI were established in the model group,low-dose Klotho group,medium-dose Klotho group and high-dose Klotho group.In the sham operation group,only carotid artery vessel separation and wound suture were performed,and carotid artery clamping was not performed.After being fed for 24 h,the rats in the low-dose,medium-dose and high-dose Klotho groups were treated with 25,50 and 100 mg/kg Klotho protein,respectively,and the rats in the model group and sham operation group were treated with equal volume of normal saline.All rats in the five groups were treated once a day,for 14 days.Longa scoring method and balance beam scoring method were used to evaluate the neurological scores of rats in each group.Cerebral tissues of rats in each group were taken after decapitation.Hematoxylin staining method was used to measure the apoptosis rate of cerebral cortex neu‑rons of rats,and receptor-interacting protein kinase 1(RIP1)and RIP3 proteins in cerebral cortex tissues of rats were de‑tected by Western blotting.The inflammatory mediators interleukin(IL)-1β,tumor necrosis factor(TNF)-αand IL-6 were detected by enzyme-linked immunoassay,MDA was detected by TBA,SOD was detected by enzyme-linked immuno‑assay,and GSH-Px was detected by ultraviolet colorimetry.Results The the neurological score and cerebral cortical neuron apoptosis rate of rats in the sham operation group were lower than those in the other groups(all P<0.05),and those in the model group were higher than those in the other groups(all P<0.05),and those in the high-dose Klotho group were higher than those in the low-dose Klotho group and medium-dose Klotho group(all P<0.05),and those in the mediumdose Klotho group were higher than those in the low-dose Klotho group(all P<0.05).The relative expression levels of RIP1 and RIP3 proteins and the expression levels of IL-1β,TNF-α,IL-6 and MDA in the cerebral cortex of rats in the sham operation group were lower than those in the other groups,while the expression levels of SOD and GSH-Px were high‑er than those in the other groups(all P<0.05).The relative expression levels of RIP1 and RIP3 proteins and the expres‑sion levels of IL-1β,TNF-α,IL-6 and MDA in cerebral cortex of rats in the model group were higher than those in the oth‑er groups,while the expression levels of SOD and GSH-Px were lower than those in the other groups(all P<0.05).The rel‑ative expression levels of RIP1 and RIP3 proteins and the expression levels of IL-1β,TNF-α,IL-6 and MDA in the cere‑bral cortex of rats in the high-dose Klotho group were lower than those in the low-dose Klotho group and medium-dose Klotho group,while the expression levels of SOD and GSH-Px were higher than those of the low-dose and medium-dose Klotho groups(all P<0.05).The relative expression levels of RIP1 and RIP3 protein and the expression levels of IL-1β,TNF-α,IL-6 and MDA in cerebral cortex of rats in the medium-dose Klotho group were lower than those in the low-dose Klotho group,while the expression levels of SOD and GSH-Px were higher than those in the low-dose Klotho group(all P<0.05).Conclusion Gastric administration of 100 mg/kg Klotho protein can alleviate CIRI in ACI rats,and its mecha‑nism may be related to inhibiting the expression of RIP1 and RIP3 proteins in cerebral cortex and inhibiting the inflammato‑ry response and oxidative stress response at the site of brain injury.