蓝莓对酒精性肝损伤大鼠肝组织TLR4表达的影响

Effect of blueberry on hepatic expression of TLR4 in a rat model of alcoholic liver injury

目的:探讨蓝莓对酒精性肝损伤大鼠的保护作用及可能机制.方法:48只健康SD大鼠随机均分为4组:正常组、蓝莓组、异甘草酸镁组及模型组.除正常组不灌胃乙醇溶液,给予等体积生理盐水外,其余各组均使用560 mL/L的乙醇溶液灌胃.蓝莓组与异甘草酸镁组在灌乙醇溶液1 h后分别灌服蓝莓原浆及异甘草酸镁溶液.4 wk后处死所有大鼠.HE染色观察各组肝脏形态变化,采用自动生化仪检测血清谷丙转氨酶(alanine aminotransferase,ALT)、谷草转氨酶(aspartate aminotransferase,AST)、甘油三酯(triglyceride,TG)、总胆固醇(total cholesterol,TC)含量;Elisa法测定肝组织匀浆中超氧化物歧化酶(superoxide dismutase,SOD)活性、肿瘤坏死因子α(tumor necrosis factor alpha,TNF-α)及白介素-8(interleukin8,IL-8)的含量;RT-PCR、Western blot检测大鼠肝组织中Toll样受体4(Toll-likereceptor 4,TLR4)的表达.结果:正常组大鼠HE染色未见异常,模型组HE病理切片出现弥漫性空泡,部分区域出现炎症细胞浸润,蓝莓组与异甘草酸镁组明显少见.与蓝莓组及异甘草酸镁组比较,模型组大鼠血清ALT、AST、TG、TC含量明显升高(F=47.984,14.974,149.338,94.896,均P<0.01);蓝莓组及异甘草酸镁组肝组织中SOD的蛋白活性明显高于模型组(F=35.390,P<0.01),而TNF-α、IL-8含量、TL R4 mRNA和蛋白质的表达明显低于模型组(F=76.250,37.971,141.932,62.750,均P<0.01).结论:蓝莓对酒精性肝损伤大鼠有较好的保护的作用,其机制可能与下调肝组织中TLR4的表达,并降低肝组织中TNF-α、IL-8的含量,提高SOD活性相关.

AIM：To investigate the protective effect of blueberry in rats with alcoholic hepatic injury and explore the possible mechanism.METHODS：Forty-eight healthy SD rats were randomly divided into a control group,a blueberry group,a magnesium isoglycyrrhizinate group and a model group.The rats in the control group were given physiological saline,and other groups were all given 56 mL/L ethanol solution intragastrically.The blueberry group and magnesium isoglycyrrhizinate group were,respectively,given blueberry juice and magnesium isoglycyrrhizinate solution 1 h after intragastric alcohol infusion.All SD rats were sacrificed after 4 wk.Pathological changes in the hepatic tissue were assessed by hematoxylin-eosin（HE） staining,and alanine aminotransferase（ALT）,aspartate aminotransferase（AST）,triglyceride（TG） and total cholesterol（TC） in serum were detected with automatic biochemical analyzer.The activity an of superoxide dismutase（SOD）,the contents of tumor necrosis factor alpha（TNF-α）and interleukin 8（IL-8） in liver homogenates were determined by enzyme linked immunosorbent assay（ELISA）.The expression of Toll-like receptor 4（TLR4） in liver tissue was detected by reverse transcription-PCR（RT-PCR） and Western blot.RESULTS：In the control group,hepatocytes were intact,and no vacuoles were observed.In the model group,vacuoles were noted in the cytoplasm of hepatocytes.The degree of cytoplasmic vacuolation was significantly alleviated in the blueberry group and magnesium isoglycyrrhizinate group.The levies of ALT,AST,TG,and TC in the model group were significantly higher than those in the blueberry group and magnesium isoglycyrrhizinate group（F = 47.984,14.974,149.338,94.896,P 〈 0.01 for all）.Compared with the model group,the activities of SOD in liver homogenates were significantly higher（F = 33.102,P 〈 0.01） and the contents of TNF-α and IL-8 in liver homogenates were significantly lower（F = 76.250,37.971,P 〈0.01 for both） in the blueberry group and magnesium isoglycyrrhizinate group.The expression of hepatic TLR4 in the model group was significantly higher than that in the blueberry group and magnesium isoglycyrrhizinate group（F = 141.932,62.750,P〈0.01 for both）.CONCLUSION：Blueberry exerts a protective effect on alcoholic hepatic injury in rats,and the mechanism might be associated with down-regulating the expression of TLR4,reducing the contents of hepatic TNF-a and IL-8,and up-regulating the activity of hepatic SOD.