Wojcik B, Miklosz A, Zabielski P, Chabowski A, Gorski J
Departments of Physiology, Medical University of Bialystok, Bialystok, Poland.
Department of Medical Biology, Medical University of Bialystok, Bialystok, Poland.
J Physiol Pharmacol. 2017 Oct;68(5):731-736.
There is a convincing piece of evidence showing that most of free fatty acids (FFA) entering cardiomyocytes are first esterified into triacylglycerols (TG) before being oxidized or used for synthesis of complex lipids. The enzyme adipose triglyceride lipase (ATGL) initiates lipolysis of TG by hydrolyzing the first ester bond of the compound. As a result, free fatty acid and diacylglycerol (DG) are released in that process. Finally, DG may be further hydrolyzed by the enzyme hormone sensitive lipase (HSL). The aim of the present study was to examine effect of tachycardia on mRNA and protein expression of ATGL, CGI-58 (an activator of ATGL), G0S2 (an inhibitor of ATGL) and HSL in the left and right ventricle of the rat. The experiments were carried out on male Wistar rats, 240 - 260 grams of body weight. After anesthesia, two electrodes were inserted in the right jugular vein and connected to SC-04 stimulator. The rats were randomly allocated into one of the three groups, namely: control, 30 min and 60 min of the heart stimulation at the rate of 600 times/min. The expressions of ATGL, CGI-58, G0S2 and HSL were evaluated at both gene and protein levels using real-time PCR and Western Blot analysis, respectively. Both 30 and 60 min stimulation reduced ATGL, HSL, CGI-58 and G0S2 mRNA content in the left ventricle. The stimulation had only insignificant impact on ATGL, HSL and CGI-58 transcript levels in the right ventricle. Interestingly, Western Blot analysis showed that the stimulation, regardless of the time, reduced the ATGL and G0S2 protein expression, but did not change the CGI-58 and HSL expression in the left ventricle. Furthermore, in the right ventricle, the protein expressions of ATGL, HSL and G0S2 decreased after stimulation. In conclusion, the obtained results clearly show that tachycardia affects both mRNA and protein expression of particular compounds of the TG lipolytic system in the heart ventricles. Additionally, there are marked differences in the expressions of the examined compounds between the ventricles.
有确凿证据表明，进入心肌细胞的大多数游离脂肪酸（FFA）在被氧化或用于合成复合脂质之前，首先会被酯化为三酰甘油（TG）。脂肪甘油三酯脂肪酶（ATGL）通过水解该化合物的第一个酯键启动TG的脂解作用。结果，在此过程中释放出游离脂肪酸和二酰甘油（DG）。最后，DG可能会被激素敏感性脂肪酶（HSL）进一步水解。本研究的目的是检测心动过速对大鼠左、右心室中ATGL、CGI-58（ATGL的激活剂）、G0S2（ATGL的抑制剂）和HSL的mRNA和蛋白表达的影响。实验在体重240 - 260克的雄性Wistar大鼠身上进行。麻醉后，将两个电极插入右颈静脉并连接到SC-04刺激器。大鼠被随机分为三组之一，即：对照组、以600次/分钟的频率进行30分钟和60分钟心脏刺激组。分别使用实时PCR和蛋白质印迹分析在基因和蛋白质水平评估ATGL、CGI-58、G0S2和HSL的表达。30分钟和60分钟的刺激均降低了左心室中ATGL、HSL、CGI-58和G0S2的mRNA含量。该刺激对右心室中ATGL、HSL和CGI-58的转录水平仅有微不足道的影响。有趣的是，蛋白质印迹分析表明，无论刺激时间长短，该刺激均降低了左心室中ATGL和G0S2的蛋白表达，但未改变CGI-58和HSL的表达。此外，在右心室中，刺激后ATGL、HSL和G0S2的蛋白表达降低。总之，所得结果清楚地表明，心动过速会影响心室中TG脂解系统特定化合物的mRNA和蛋白表达。此外，所检测化合物在心室之间的表达存在显著差异。
