A021: Hypoxic Complex Exercise Promotes HIF-1Α Expression to ImproveDrosophila Cardiac Pumping Function

Background: Some studies have shown that the stability and transcription of HIF-1Α significantly increases under hypoxic conditions, and HIF and its downstream targets are becoming a new choice for the treatment of various organ injuries to improve physical function. Combined with the team's pre-screening of suitable hypoxic compound exercise protocols, this study aimed to explore the link between the expression of exercise HIF-1Α under hypoxic conditions and cardiac function, in order to provide a realistic and theoretical basis for the improvement of cardiac function by hypoxic compound exercise. Methods: 300 <italic>Drosophila</italic> flies of wild-type <italic>W¹¹¹⁸⁸</italic> strain feathered within 12 hours were collected and randomly divided into control (NC), hypoxic quiet (HC), normoxic exercise (NE), and intermittent hypoxic training (HE) groups, with 100 <italic>Drosophila</italic> in each group, and were subjected to intermittent hypoxic, normoxic and hypoxic combined exercise interventions for 5 consecutive days, lasting for one hour per day, at the age of 7 days, respectively. The gas used in both HC and HE groups was a mixture of 6% O2 and 94% N2. At 24 h after the intervention, the changes of cardiac actin were observed by F-actin staining, the changes of HIF-1Α expression level in the heart were detected by RT-qPCR, and 30 s of Drosophila heart beats were captured by an EM-CCD digital video camera (130 frames/s) to quantify the indexes of Drosophila cardiac pumping function. Results: Compared with the NC group, HIF-1Α expression increased in the heart after hypoxic compound exercise (P &lt; 0.001), the diameter of the heart tube became larger, the arrangement of cardiac myofilaments was tighter and neater, the systolic diameter of the heart increased (P &lt; 0.05), the diastolic diameter increased (P &lt; 0.001), and the shortening fraction improved (P &lt; 0.001). Compared with the NC group, HIF-1Α expression did not change significantly in the NE group, and the heart had an increased systolic diameter (P &lt; 0.05), an increased diastolic diameter (P &lt; 0.001), and a slightly improved shortening fraction. Compared with the NC group, after intermittent hypoxic exposure, cardiac HIF-1Α expression was elevated, the diameter of the heart became smaller, myocardial myofilaments were irregularly arranged, the systolic and diastolic diameters did not change significantly, and the shortening fraction was slightly increased. Conclusion: Hypoxic compound exercise promoted HIF-1Α expression in the heart and improved cardiac pumping function.