Aim To study the protective effect of Ghrelin against liver injury induced by lipopolysaccharide ( LPS ) insult and to explore its potential molecular mechanism.Methods L-02 liver cell lines were cultured in vitro and challenged with LPS to induce injury.Reverse Transcription-PCR assay was used to measure mRNA expression of endogenous Ghrelin and its receptor, growth hormone ( GH ) secretagogue receptor ( GHSR )1a, Western blot to evaluate NF-ΚB protein level in nuclei, and Hoechst-staining to detect apoptosis in cells.Results Compared with the controls , LPS ( 5 mg·L-1 ) treatment significantly increased mRNA level of endogenous Ghrelin and GH-SR1a in L-02 liver cells, induced more content of p65, a subunit of NF-ΚB protein, in nuclei, and caused more cell apoptosis, respectively.While, Gh-relin( 10 nmol·L-1 ) co-incubation remarkably inhibited the p65 nuclear translocation and attenuated the cell apoptosis induced by LPS insult, respectively.Conclusions Endogenous Ghrelin and its receptor are up-regulated in liver injury induced by LPS insult, and supplement of exogenous Ghrelin remarkably protects liver cells against LPS-induced apoptosis through the inhibition of nuclear translocation of NF-ΚB.The increased Ghrelin and its receptor may play an important protective role in liver injury induced through inflammation through inhibition of the downstream pathway of NF-ΚB activation signaling.%目的 研究Ghrelin对内毒素(lipopolysaccharide,LPS)肝损伤的保护作用,并探讨潜在的分子药理学作用机制.方法 体外培养肝细胞L-O2细胞株,建立LPS损伤模型,采用Reverse Transcription-PCR评价细胞内源性Ghrelin前体原及其受体GHSR1a的mRNA表达水平,外源性Ghre-lin处理细胞后,Western blot检测评价NF-κB蛋白的核转位情况,Hoechst染色方法检测细胞凋亡.结果 5 mg·L-1的LPS处理肝细胞L-O2可诱导内源性Ghrelin及其受体GHSR1a的表达上调.5 mg·L-1的LPS刺激2.5 h诱导肝细胞核内NF-κB的含量增高,刺激24 h诱导大量肝细胞凋亡,而10 mol·L-1的Ghrelin预处理明显降低肝细胞核内NF-κB的含量,抑制LPS的促凋亡作用.结论 LPS诱导肝损伤时,内源性Ghrelin及其受体GHSR1a均表达上调,而外源性Ghrelin通过抑制LPS诱导的NF-κB的核转位拮抗其诱导的细胞凋亡,提示感染性肝损伤时,Ghrelin及其受体信号的上调可能通过抑制NF-κB介导的炎症反应,从而实现肝细胞的保护作用.
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