中文摘要：

目的探讨PACS-2（phosphofurinacidicclustersortingprotein一2）及其所调控的葡糖调节蛋白78（glucoseregulatingprotein，GRP78）和细胞凋亡标志蛋白Bax、Caspase-3在非酒精性脂肪性肝病（non—alcoholicfattyliverdisease，NAFLD）中的表达变化及意义。方法应用软脂酸诱导HepG2细胞脂肪变建立非酒精性脂肪性肝病体外模型，并按0、4、8、12、24h时相点收获细胞，通过油红O（0ilred）染色检测细胞脂肪变程度。同时应用高脂饮食喂sD大鼠建立NAFLD模型，并按时相点分为4、8、12、16、20周组，以普通饮食喂养为对照组。通过q-PCR及Westernblot检测PACS-2及内质网应激标志蛋白GRIt78和Bax、Caspase．3的表达。结果软脂酸成功诱导HepG2细胞脂肪变性，应用高脂饮食喂养sD大鼠成功建立NAFLD大鼠模型。与对照组相比，PACS-2mRNA相对表达量在HepG2细胞脂肪变模型早期（4、8h）下降，脂肪变模型晚期（12、24h）升高；GRP78在8h组开始上升后，24h组达到高峰（P〈0．01）；Bax、Caspase-3的表达均在12、24h组显著上升（P〈0．01）。在蛋白水平上，PACS-2、GRP78、Bax、Caspase-3的表达与mRNA水平表达基本一致（P〈0．01）。NAFLD大鼠模型蛋白表达上，与对照组相比，PACS．2同样在早期（4．8周）下降，晚期（16、20周）上升（P〈0．01）；GRP78在表达在4周上调后，20周达到高峰（P〈0．01）。Bax、Caspase-3的表达均在晚期显著上升（P〈0．01）。结论PACS-2早期的低表达可能参与了NAFLD过程中的内质网应激，晚期升高可能与肝细胞凋亡所致的肝损伤密切相关。

英文摘要：

Objective To clarify the expression change and significance of phosphofurin acidic cluster sorting protein-2 （ PACS-2 ） in non-alcoholic fatty liver disease （ NAFLD ）. Methods An in vitro NAFLD model was established by inducing the steatosis of HepG2 cells using palmitic acid. The cells were collected at the time points of 0, 4, 8, 12, and 24 h after induction. The steatosis levels were measured by oil red staining. Rat NAFLD model was established in SD rats by feeding high fat diet, while the rats fed with normal food were set as control group. These rats were killed at 4, 8. 12, 16 and 20 weeks after feeding. The expression of PACS-2, endoplasmic reticulum stress marker-glucose, regulating protein 78 （ GRP78 ） , Bax and Caspase-3 in the cell model and liver tissue samples were detected by q-PCR and Western blotting. Results The steatosis of HepG2 cells was induced by fatty acid successfully. The rat NAFLD model was established in SD rats successfully. The relative expression of PACS-2 at mRNA level was significantly decreased in the early stages （4 and 8 h）, but increased in the late stages （12 and 24 h after treatment）. That of GRP78 was up-regulated in 8 h, and then reached the highest level in 24 h after induction （P 〈 0.01 ）. That of Bax and Caspase-3 was also significantly increased in 12 and 24 h （P 〈 0.01 ）. The expression of these proteins showed similar trends as those at mRNA level （P 〈0.01 ）. In the rat NAFLD model, the expression of PACS-2 protein