杜仲不同部位及不同提取方法的提取物对大鼠肝脏缺血再灌注损伤的保护作用

Protective effects of extracts from different parts of Eucommia ulmoides and by different extraction methods against hepatic ischemia-reperfusion injury in rats

背景与目的:已有研究证实杜仲提取物具有抗炎、抗氧化作用,且对器官缺血再灌注损伤具有保护作用,但杜仲的不同部位及不同提取方法所得提取物的药理效应有所不同。本研究对比性研究杜仲叶与皮的不同提取物对大鼠肝缺血再灌注损伤(HIRI)的保护作用,以期为临床HIRI的防治提供给参考。方法:48只雄性SD大鼠随机分均为假手术组、HIRI模型组与4个预处理组。4个预处理组大鼠分别用杜仲皮水提取物、杜仲皮醇提取物、杜仲叶水提取物、杜仲叶醇提取物灌胃,1次/d,连续10 d,提取物浓度80 g生药/kg;假手术组、HIRI模型组用等体积生理盐水按相同的方式灌胃,第11天,除假手术组行假手术外,其余各组采用阻断左肝叶及肝中叶血供1 h后再灌4 h的方式诱导HIRI,随后采集各组大鼠左肝叶与下腔静脉取血标本,用HE染色法观察肝脏病理变化,检测血清肝功能指标丙转氨酶(ALT)、谷草转氨酶(AST)以及肝组织中炎性指标肿瘤坏死因子α(TNF-α)、白细胞介素1β(IL-1β)与氧化应激指标丙二醛(MDA)、超氧化物歧化酶(SOD)。结果:除假手术组外,其余各组大鼠肝组织均有不同程度的病理改变,但各预处理组的肝损伤情况均较HIRI组有明显改善,其中杜仲叶醇提取物预处理的作用最为明显。与假手术组比较,HIRI模型组及各预处理组大鼠血清ALT、AST活性明显升高,肝组织TNF-α、IL-1β水平及MDA浓度明显升高,SOD活性明显降低,而各预处理组以上指标的变化程度均较HIRI模型组降低,其中杜仲叶醇提取物预处理最为明显(均P<0.05)。结论:杜仲不同部位及不同提取方法的提取物对HIRI的保护作用,尤以杜仲叶醇提取物保护作用最为显著,提示杜仲叶中的黄酮类化合物可能是抗HIRI最有效的成分,值得进一步的研究与开发。

Background and Aims:Studies have confirmed that the extracts of Eucommia ulmoides have anti-inflammatory and antioxidant effects,and offer a protective effect against organ ischemia-reperfusion injury.However,the pharmacological effects will vary among the extracts from different parts of Eucommia ulmoides and by different extraction methods.This study was conducted to compare the protective effects of the extracts from Eucommia bark and bark as well as by different extraction methods on liver ischemia-reperfusion injury (HIRI),so as to provide reference for the prevention and treatment of HIRI in clinical practice.Methods:Forty-eight male SD rats were equally randomized into sham operation group,HIRI model group,and 4 different pretreatment groups.Rats in the 4 pretreatment groups underwent gavage with Eucommia bark water extract,Eucommia bark ethanol extract,Eucommia leaf water extract and Eucommia leaf ethanol extract,respectively,once per day,for 10 d,and the concentration of each extract was 80 g crude drug/kg.Rats in sham operation group and HIRI model group were given the saline of the same volume in the same fashion.On the 11th day,except the rats in sham operation group HIRI was induced in all rats in the other groups by means of 1-h occlusion of the blood supply for the left hepatic lobe and the middle hepatic lobe followed by 4-h reperfusion.After that,the specimens of left hepatic lobe and blood sample from the inferior vena cava were harvested.Then,the pathological changes of the liver were observed by HE staining,and the serum liver function parameters alanine aminotransferase (ALT) and aspartate aminotransferase (AST),and the inflammatory index tumor necrosis factor-α (TNF-α),interleukin-1β (IL-1β) as well as the oxidative stress variables malondialdehyde (MDA) and superoxide dismutase (SOD) in the liver tissue were determined.Results:Except the sham operation group,pathological changes of the liver tissue of different degrees were presented in all remaining groups of rats,but the liver injuries were milder in all pretreatment group that that in HIRI model group,particularly in Eucommia leaf ethanol extract pretreatment group.Compared with sham operation group,the activities of serum ALT and AST were significantly increased,the TNF-α and IL-1β levels and MOD concentrations in the liver tissue were significantly increased,while the SOD activities in the liver tissue were significantly decreased in HIRI group and all pretreatment group,but the changing amplitudes in all above parameters were lower in each pretreatment group than those in HIRI group,particularly those in Eucommia leaf ethanol extract pretreatment group (all P<0.05).Conclusion:The extracts from different parts of Eucommia ulmoides and by different extraction methods all have protective effects against HIRI,especially,the ethanol extract from Eucommia leaves has most evident protective effect,suggesting that the flavonoids in the Eucommia leaves is the most effective compounds against HIRI,which deserves to be further explored and developed.