The Protective Effects and Underlying Mechanisms of a New Synthetic Derivative of Caffeic Acid on Cardiomyocytes under Oxidative Stress
| Autor: | Mong-Han Li, 李孟翰 |
|---|---|
| Rok vydání: | 2014 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 102 Background: Ischemic heart disease is one of the most prevalent cardiovascular problems in the world. Once ischemia occurs, restoration of blood flow as soon as possible is necessary for minimizing the damage to the least. However, reperfusion injury may even lead to more horrible outcome to the heart. As far, there is still no guideline for treatment of reperfusion injury. Caffeic acid is recognized as a good antioxidant and proved beneficial for cardioprotection by previous works. In this study, we try to figure out whether a synthetic caffeic acid derivative, compound 36-12, has cardioprotective effects under oxidative stress, and investigate the underlying mechanisms as well. Methods and Results: In this study, 50 μM H2O2 was used to induce oxidative stress in H9c2 cell line to mimic myocardial reperfusion injury. Firstly, we examined the protective effect of compound 36-12 by MTT assay, and compared it with NAC, a well-known antioxidant. Secondly, we measured intracellular ROS level by fluorescent probes to observe antioxidant activity of the drug. Besides, we also used different protein inhibitors to block signaling pathways which make contribution to cardioprotection, and then observed whether the protective effects of compound 36-12 was influenced by doing so. Lastly, activation extents of these proteins at different time points under oxidative stress were shown by Western blotting. Results showed that 3 μM compound 36-12 not only enhanced cell viability but also reduced intracellular ROS level under oxidative stress significantly. This protective effect was comparable to 50 μM NAC. Then, we found that the protective effect of compound 36-12 was totally abolished by STAT3 inhibition, and its ROS scavenging activity was attenuated as well. On the other hand, JAK2 inhibition could enhance cell viability and lower intracellular ROS level under oxidative stress. The results by Western blotting showed that compound 36-12 provoked STAT3 and AMPK phosphorylation obviously. At the same time, however, it also diminished the phosphorylation extent of ERK, as well as H2O2-induced phosphorylation of eNOS and JAK2. Conclusion: Compound 36-12 shows marvelously cardioprotective and ROS scavenging effects under oxidative stress, which have something to do with activation of STAT3 and inhibition of JAK2. Besides, the phosphorylation of STAT3 induced by compound 36-12, is through a JAK2-independent mechanism. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
| Externí odkaz: |
|