跨膜蛋白16A在胆汁淤积性肝硬化门脉高压大鼠血管重构中的意义

Role of transmembrane protein 16A in vascular remodeling in portal hypertension induced by bile duct ligation of SD rats

目的 探讨跨膜蛋白16A（TMEM16A）在胆汁淤积性肝硬化门脉高压大鼠门静脉重构中的作用及其机制.方法 将60只雄性SD大鼠随机分为模型组（n=40）及假手术对照组（n=20）,模型组结扎胆管制备胆汁淤积性肝硬化门脉高压模型,4周后取材.通过肝脏苏木素-伊红（HE）染色和测量门静脉压力判断是否造模成功.HE染色观察大鼠门静脉组织学形态变化,采用免疫组织化学法、Western blot检测门静脉TMEM16A、磷酸化细胞外信号调节激酶1/2（p-ERK1/2）、细胞外信号调节激酶1/2（ERK1/2）表达的变化.结果 与对照组比较,模型组大鼠肝脏有假小叶形成,呈肝硬化改变,且门静脉压力升高[（16.79±2.65） mmHg（1 mmHg=0.133 kPa）比（8.86±0.53） mmHg,P＜0.05],其中膜厚度显著增加[（43.27±9.62） μm比（21.75 ±5.56） μm,P＜0.05],TMEM16A表达下降,p-ERK1/2表达增高,ERK1/2表达无明显变化.结论 TMEM16A可能通过影响丝裂原活化蛋白激酶（MAPK）/ERK通路活性来调控门静脉平滑肌细胞增殖,其下调可能在门脉高压导致的门静脉重构中起重要作用.

Objective To investigate the role of transmembrane protein 16A （TMEM16A） in murine portal vein remodeling in cirrhotic portal hypertension induced by bile duct ligation （BDL）.Methods Sixty male SD rats were randomly divided into the model group （n =40） and the control group （n =20）.Rats in the model group were subjected to BDL.Animals were sacrificed at 4th week.Hematoxylin and eosin （HE） staining was used to observe the liver cirrhosis in rats,and the portal vein pressure was measured to determine portal hypertension in rats.The change of histological structure of the portal vein was observed by HE staining.In addition,immunohistochemistry and Western blotting were applied to detect the expression of TMEM16A,phosphorylated extracellular signal-regulated kinase 1/2 （p-ERK1/2） and extracellular signal-regulated kinase 1/2 （ERK1/2） proteins.Results Compared with sham control group,the liver of rats in model group had false lobules and the portal vein pressure significantly increased [（16.79 ±2.65） mmHg （1 mmHg =0.133 kPa） vs.（8.86 ±0.53） mmHg,P 〈0.05].And the intima-media thickness of portal vein in model group was increased as compared with sham control group [（43.27 ±9.62） μm vs.（21.75 ± 5.56） μm,P 〈 0.05].The protein expression of TMEM16A was significantly decreased,and that of p-ERK1/2 was significantly increased in model group as compared with sham control group.The protein expression of ERK1/2 almost had no changes.Conclusion TMEM16A may regulate the proliferation of portal vein smooth muscle cells by influencing the activity of mitogen-activated protein kinase （MAPK）/ERK signal pathway.Downregulation of TMEM16A may play an important role in the occurrence of portal vein remodeling induced by portal hypertension.