Essential Oil from Alpiniae Zerumbet Fructus Alleviates High Glucose-induced HUVEC Injury via TXNIP Signaling Pathway / 中国实验方剂学杂志

ABSTRACT

Objective:To study the protective effect of essential oil from Alpiniae Zerumbet Fructus （EOAZF） against high glucose （HG）-induced injury of human umbilical vein endothelial cells （HUVECs） <italic>in vitro</italic>， so as to provide experimental evidence for the treatment of diabetes-induced cardiovascular diseases with EOAZF. Method:The cells were divided into the normal group， model group （25 mmol·L^-1 glucose）， positive control group （100 mg·L^-1 vitamin C）， and the low- （0.25 μg·L^-1）， medium- （1 μg·L^-1）， and high-dose （4 μg·L^-1） EOAZF groups. The HUVECs were damaged by HG. The secretion amounts of malondialdehyde （MDA）， nitric oxide （NO）， and endothelin-1 （ET-1） in HUVECs of different groups were measured to assess the protective effect of EOAZF against HG-induced injury. The effects of EOAZF on the apoptosis and reactive oxygen species （ROS） generation of HUVECs damaged by HG were detected by Annexin V-fluorescein isothiocyanate/propidium iodide （Annexin V-FITC/PI） staining and dichloro-dihydro-fluorescein diacetate （DCFH-DA） assay. The protein and mRNA expression levels of thioredoxin interacting protein （TXNIP） and thioredoxin 1 （Trx-1） were determined by Western blot and Real-time polymerase chain reaction （Real-time PCR）， followed by the measurement of total intracellular Trx-1 activity with insulin disulfide reduction method. Result:The comparison with the control group revealed that the proliferation of HUVECs in the model group was significantly inhibited and their shape was damaged. Compared with the model group， EOAZF protected HUVECs against HG-induced injury in a concentration-dependent manner. The secretion amounts of MDA and ET-1 （<italic>P</italic><0.05） in the model group were increased in contrast to those in the control group， while the NO level was decreased （<italic>P</italic><0.01）. Compared with the model group， EOAZF at all the three concentrations， especially at 4 μg·L^-1， obviously reduced the secretion of MDA and ET-1 （<italic>P</italic><0.05）， but elevated NO after HG induction （<italic>P</italic><0.05）. The cell apoptosis assay and ROS detection results demonstrated that the apoptosis and ROS level in the model group were higher than those in the control group （<italic>P</italic><0.01）. Compared with the model group， EOAZF at 4 μg·L^-1significantly lowered the ROS level and apoptosis （<italic>P</italic><0.05） of HUVECs damaged by HG. The Western blot assay and Trx-1 activity detection uncovered that the protein and mRNA expression levels of TXNIP in the model group were significantly up-regulated as compared with those in the control group （<italic>P</italic><0.05）， whereas the Trx-1 activity was decreased （<italic>P</italic><0.01）. Compared with the model group， EOAZF at 4 μg·L^-1significantly down-regulated the mRNA and protein （<italic>P</italic><0.05） expression levels of TXNIP and enhanced the total Trx-1 activity （<italic>P</italic><0.05） in HUVECs， thus suppressing the oxidative stress. Conclusion:EOAZF exerts the protective effects against HG-induced injury in HUVECs by improving the endothelial function and reducing intracellular ROS and apoptosis. Its efficacy in anti-oxidative stress may be related to the down-regulation of mRNA and protein expression levels of TXNIP and the enhancement of Trx-1 activity.