Effect of aerobic training and octopamine on the gene expression of LAMP2A, Parkin and concentration OF SOD in liver of male rats fed with repeated heated oil

Background & Objective: Mitochondria are the most important sites for the production of energy and lipids, nucleic acids and amino acid precursors and are one of the most important sources for the production of reactive oxygen species (ROS). Previous studies have shown that mitochondrial dysfunction increases ROS and oxidative stress, which are associated with diseases such as obesity, diabetes and cancer. Today, cooking oil consumption has increased worldwide. During heating, oils are continuously oxidized, releasing lipid hydroperoxides and finally free radicals. Free radicals and oxidative stress in heated oils affect the bodychr(chr('39')39chr('39'))s energy production sources such as mitochondria. Therefore, to maintain energy production, mitochondria need to activate factors that can remove damaged parts of the mitochondria to achieve a healthier mitochondrial network by reducing ROS production and mitochondrial biogenesis. This process of selective removal of the affected part of the mitochondria is a form of autophagy called mitophagy. Lysosome-associated membrane protein 2A (LAMP2A) is a lysosome membrane receptor to which damaged proteins attach, enter the lysosome, and break down. LAMP2A acts as an autophagy and its downregulation induces autophagy. Parkin protein is an E3 ubiquitin ligase and acts as a mitophagy in removing damaged mitochondria in various tissues of the body. Exercise has recently been recognized as an effective way to increase mitochondrial function, and the role of exercise in improving mitochondrial damage and oxidative stress in various diseases has been reported. On the other hand, today, researchers are paying attention to sports supplements to reduce the physiological damage caused by exercise such as oxidative stress. One of these supplements is octopamine, which according to studies has antioxidant properties and stimulates fat metabolism. The aim of this study was to determine the effect of aerobic training and octopamine on LAMP2A and parkin gene expression and SOD concentration in the liver tissue of male Wistar rats fed with the repeated heated oil . Methods: In an experimental study, 25 adult male Wistar rats weighing an average of 300 to 350 g and aged 8 weeks were purchased. All the rats were kept in polycarbonate cages (5 mice per cage) at 22 ± 2 ° C, 55% humidity and under the light and dark cycle for 12:12 hours without restriction on water and food. All the rats were randomly divided into five groups, healthy control group (n=5), DFO group (n=5), aerobic training + DFO group (n=5), octopamine + DFO group (n=5) and aerobic training + octopamine + DFO group (n=5). Intraperitoneal injection of octopamine and Gavage of repeated heated oil were done five times a week and every day, respectively. The aerobic training protocol consisted of 4 weeks of aerobic training and 5 sessions per week. The training session included 5 minutes of warm-up at 7 m / min and 5 minutes of cooling at 5 m / min. The intensity of training started in the first week with 50% vo2max and a speed of 16 m / min, and in the last week it reached 65% Vo2max and a speed of 26 m / min. 48 hours after the last training session and 8 hours of fasting, all the rats were anesthetized with chloroform and then sacrificed. Blood samples were taken directly from the liver by heparin-soaked syringe and the liver tissue was immediately removed from the body and stored in a nitrogen tank at -80 ° C. Gene expression of LAMP2A and Parkin were measured by Real time-PCR and SOD concentration was measured by ELISA test. One-way ANOVA and Tukey post hoc test were used to analysis the data. The significant level was set at p<0.05.   Results: The results showed that consumption of repeated heated oil induced significant increase in gene expression of Parkin (P < 0.05) and significant decrease in gene expression of LAMP2A (P < 0.05) and concentration of SOD (P < 0.05) compared to healthy control group. The aerobic training caused increase in SOD concentration and non significant difference in gene expression of  Parkin (P >0.05) and LAMP2A (P >0.05) compared to DFO group. Interaction effect of aerobic training and octopamine caused the significant increase in gene expression of SOD concentration (P <0.05) and non significant difference in Parkin and LAMP2A gene expression (P >0.05) in comparison with DFO group. Discussion: Regarding the incremental effect of aerobic training on SOD concentration, it is likely that due to aerobic training, Nrf2 activity increases, and isolation of the Nrf2-Kaep1 complex, and binding of Nrf2 to the antioxidant responsive element occurs. Subsequently, the transcription of the antioxidant genes, that is SOD, takes place and it is increased.  The antioxidant properties of octopamine in interaction with the effect of aerobic training have also been able to significantly increase the concentration of SOD. Regarding the effect of aerobic training and octopamine consumption alone on the expression of the LAMP2A gene, it is likely that they exert their effect by reducing oxidative stress and increasing the inhibition of AKT1, which increases antioxidant activity in the liver tissue cells. The interactive effect of aerobic training and octopamine also showed an insignificant increase in LAMP2A gene expression compared to the DFO group, but this increase is physiologically beneficial. In contrast, Parkin gene expression showed an insignificant decrease due to aerobic training and octopamine consumption alone and simultaneously, indicating an increase in the activity of antioxidants, including SOD, which decreases oxidative stress and consequently reduces mitophagy (decreased expression of Parkin gene) in the liver tissue, by varying the intensity, duration of training, and dose of octopamine, better results may be obtained. In general, it seems that the interaction of aerobic training and octopamine can improve antioxidants and mitophagy in the liver.