The Role And Preliminarymechanism Of Plin5 In Heart Failuremice

Heart failure(HF) is the disease of myocardial systolic function abating and reducing the amount of blood of the heart pumps. Heart can’t beat out enough blood tissue metabolism needs. HF is a common outcome of various cardiovascular diseases. In normal circumstances, the heart of most of the energy is derived from the oxidation of fatty acid. But in the heart failure occurs, the energy metabolism of myocardial cells occur obvious changes, also the fatty acid metabolism appear obvious abnormally. Studies have shown that, the occurrence of heart failure was due to the imbalance of ATP between produced by heart fatty acids beta oxidation to its demand.At present, the lipid droplets are considered to be the "organelles" of metabolic actively. Lipid droplets play a very important role in the metabolism and storage of lipid. The lipid droplet-associated proteins are the important molecular of regulating metabolism of lipid droplets. Plin5, a lipid droplet-associated protein, is the fifth member of the PAT family, plays a very important role in the process of fatty acid metabolism, Plin5 is mainly exist in oxidative tissues, including the heart, liver, BAT and skeletal muscle. At the same time, Plin5 is also named as perilipin 5, LSDP5, OXPAT or MLDP. Past studies have shown that, Plin5 knockout can speed up the lipolysis and fatty acid oxidation, resulting in cardiac lipid toxic injury.This experiment established the animal model of heart failure through transverse aortic constriction(TAC) in Plin5 knockout mice, to research the role and the molecular mechanism of Plin5 in heart failure, provide reference for the treatment of heart failure.1. TAC surgery leads to myocardial hypertrophy and myocardial hypertrophy is more serious in Plin5 knockout mice, and Plin5 deficiency exacerbated heart function decline caused by TAC mice.Experiments mice are divided into four groups, respectively is WT control group, WT surgery group, control group of Plin5 knockout and surgery group of Plin5 knockout. Treat with TAC surgery for the surgery group at 8-week old. Four weeks after surgery, calculate the results of mice heart weight(HW) /mice body weight(BW). At the same time, Mice heart frozen section, HE staining, and then statistics myocyte cross-sectional area using Cell Sens Entry software randomly selected five different views. We found that the HW/BW and the myocyte cross-sectional area were obviously higher in Plin5 knockout mice than the WT group after TAC surgery. Hinted Plin5 deficiency added the degree of myocardial hypertrophy caused by TAC surgery.Four weeks after surgery, application of ultrasonic instrument and high frequency probe two-dimensional echocardiographic examination, measurement of the left ventricular systolic internal dimension(LVID; S), ejection fraction(EF) and fraction shortening(FS) of left ventricular. We found that Plin5 deficiency exacerbated the left ventricular end systolic heart ventricular cavity expansion and heart function decline caused by TAC mice.2. Plin5 deficiency reduced the heart of lipid droplets storage and increased the number of fatty acid participation in the oxidation.Four weeks after surgery, mice heart frozen section, Oil Red O staining, we found that Plin5 deficiency reduced the heart of lipid droplets storage; at the same time, extracting the fat of each group heart tissues, detected the contents of the TAG using the test kits; detected the contents of the FFA in the serum and heart tissue. We found that the FFA levels were no significant difference in the serum, but the FFA levels increased significantly in the Plin5 knockout mice. Hinted Plin5 deficiency increased the number of fatty acid participation in the oxidation.3. Plin5 deficiency increased the number of mitochondria significantly, that reduced in heart failure mice, and Plin5 deficiency exacerbated the peroxidation damage caused by TAC surgery.Four weeks after surgery, the specimens of each heart tissue was observed by JEM-1011 transmission electron microscopy, we found that the number of mitochondria was reduced in heart failure mice after TAC surgery, but Plin5 deficiency increased the number of mitochondria significantly. At the same time, we detected the contents of proteins related with mitochondria, including Cox IV and Cytochrome C, using Western Blot and Real-Time PCR. The results were same with that observed by transmission electron microscopy.Four weeks after surgery, detected the level of lipid peroxidation in the myocardial tissue of each group mice. We found that Plin5 deficiency exacerbated the peroxidation damage caused by TAC surgery.4. Plin5 deficiency exacerbated the rise of PGC-1α and PPARα expression level in mice myocardial tissue caused by TAC surgery.Four weeks after surgery, we detected the proteins contents of PGC-1α and PPARα, using Western Blot and Real-Time PCR. The results showed that the expression levels of PGC-1α and PPARα were significantly increased after TAC surgery, meanwhile, the increases in Plin5 knockout mice were more significantly. Therefore, we thought that Plin5 deficiency exacerbated the rise of PGC-1α and PPARα expression level in mice myocardial tissue caused by TAC surgery.This experiment established the animal model of heart failure through transverse aortic constriction(TAC) in Plin5 knockout mice, to research the role of Plin5 in heart failure occurs and the possible molecular mechanism. We found that Plin5 deficiency exacerbated the left ventricular end systolic heart ventricular cavity expansion and heart function decline caused by TAC mice. We thought that Plin5 deficiency reduced the heart of lipid droplets storage and increased the number of fatty acid participation in the oxidation, and activated the PPARα, promoted the mitochondrial proliferation, quickened the oxidation rate of fatty acid, causing the overproduction of ROS in the myocardial cells, causing toxic injury, further exacerbating the degree of heart failure caused by TAC surgery.