Protective effects of histone deacetylase inhibitor on stress-induced myocardial injury in rats / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To observe the protective effects of histone deacetylase inhibitor on stress-induced myocardial injury.</p><p><b>METHODS</b>Healthy male Wistar rats were randomly divided into 3 groups( n = 6), and the stress-induced myocardial injury model was established with chronic restraint stress method. The protective effects of histone deacetylase inhibitor on stress-induced myocardial injury were observed with Trichostatin A (TSA) intervention. Histone acetylation levels in myocardium of rats were detected by Western blot method, spectrophotometry method was used to dynamically determine the activity of rat serum lactate dehydrogenase (LDH), serum creatine kinase isoenzyme-MB (CK-MB) and Caspase 3, and nagar Olsen staining were used to observe the early myocardial damage.</p><p><b>RESULTS</b>Restraint stress could significantly reduce the level of histone acetylation of myocardium in rats, and TSA intervention could inhibit the stress-induced reduction of myocardial levels of histone acetylation. Restraint stress could cause the significant increase of serum LDH activity ( P < 0.05), serum CK-MB activity ( P < 0.05), and the Caspase 3 activity of myocardial tissue (P < 0.05), and early myocardial damage also occurred during restraint stress. ISA intervention could significantly reduce the serum LDH activity (P < 0.05), the serum CK-MB activity (P < 0.05), the activity of myocardial tissue caspase 3 induced by restraint stress (P < 0.05), and the stress-induced myocardial injury was also attenuated by TSA intervention.</p><p><b>CONCLUSION</b>The histone deacetylase inhibitor TSA can protect stress-induced myocardial injury.</p>

Study of the protective effect of L-arginine on relative ischemic/reperfusion injury in myocardium of rat / 中国应用生理学杂志

<p><b>AIM</b>To explore the protective effect of L-arginine on isolated rat heart with ischemia/reperfusion injury.</p><p><b>METHODS</b>24 wistar rats were randomly divided into 3 groups (each 8): control group, ischemia group, L-arginine group. The myocardiac relatively ischemia/reperfusion models in vitro were set up by using weak current stimulating isolated rat hearts. During the pre-ischemia, post-ischemia 15 min and post-ischemia 30 min, the coronary fluid was collected for testing contents of MDA and activities of both CK and LDH. Cardiac functional indexes were recorded through Pclab. At the time of 5 min, 10 min, 20 min, 30 min after ischemia, the recovery of PRP, + DP/dt(max) and - DP/dt(max) were calculated.</p><p><b>RESULTS</b>(1) During the reperfusion, L-arginine group achieved better recovery of cardiac function than that of the ischemia group. (2) MDA content, CK and LDH activities both in the coronary fluid and in the myocardium of L-arginine group were lower than those of the ischemia group, while SOD activities in the myocardium of L-arginine group were higher than that of the ischemia group.</p><p><b>CONCLUSION</b>To some extent, L-arginine could protect the myocardium from ischemia/reperfusion injury.</p>

The delayed protection of exercise preconditioning from the relative myocardial ischemia-reperfusion injury / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore the delayed protection of exercise preconditioning from the relative myocardial ischemia-reperfusion injury.</p><p><b>METHODS</b>The experiment included the vivo experiment and the vitro experiment, 32 Wistar rats in each experiment were divided into 4 groups randomly: control group (CN), relative ischemia reperfusion group (IR), exercise preconditioning group (EP) and Exercise preconditioning + relative ischemia-reperfusion group (EI). We detected the third loading exercise time, the levels of MDA in serum in vivo experiment and the Cardiac function parameter, the levels of MDA in coronary effluent in vitro experiment.</p><p><b>RESULTS</b>(1) The vivo experiment: The third loading exercise time of EI group [(71.67 +/- 9.00) min] increased significantly compared with that of IR group [(58.67 +/- 4.13) min] (P < 0.05); The levels of MDA in serum of EP group (107.00 +/- 35.99) micromol/L and EI group [(152.23 +/- 29.94) micromol/L] decreased significantly contrasted to IR group (313.20 +/- 43.40 micromol/L) (P < 0.05). (2) The vitro experiment: The PRP (heart rate * left ventricular developed pressure) in reperfusion period of CN group and EP group were stable relatively, while it reached the peak after 30 minutes and almost recovered to the level before ischemia in EI group. The parameter of IR group recovered slightly but was lower significantly than that before ischemia. There was significant difference between the recovery rate of Cardiac function of EI group and that of IR group. The increase of MDA in coronary effluent after Ischemia-reperfusion of EP group (0.34 +/- 0.24 micromol/L) and EI group [(0.41 +/- 0.26) micromol/L] decreased significantly contrasted to that of IR group [(1.27 +/- 0.52) micromol/L] (P < 0.05).</p><p><b>CONCLUSION</b>EP has the obvious delayed protection from the relative myocardial ischemia-reperfusion injury.</p>