Administration of Phospholipids with Polyunsaturated Fatty Acids in the Tail Groups Makes it Possible to Prevent a Decrease of Sperm Motility in the Fruit Fly Drosophila melanogaster in the Early Period of Readaptation after Space Flight

The aim of this study was an attempt to prevent the decrease in sperm motility of the fruit fly Drosophila melanogaster that occurs in the early period of readaptation after space flight by adding phospholipids with polyunsaturated fatty acids in the tail groups (essential phospholipids) to the nutrient medium. The study was carried out as part of space flights on board the Russian segment of the ISS during the periods of September 15, 2023–September 27, 2023 (ISS-69) and March 23, 2024–April 6, 2024 (ISS-70). The content of cytoskeletal proteins in the testes was determined by Western blotting and sperm motility by video recording and subsequent analysis. The results of the study show that modification of the nutrient medium by adding essential phospholipids leads to a decrease in cholesterol content and an increase in actin content, which prevents a decrease in tubulin content and a decrease in the speed of movement of fruit fly sperm in the early period of readaptation (up to 16 hours) after space flight. The data we obtained, on the one hand, demonstrate a possible mechanism for triggering mechanotransduction, and on the other, allow us to propose essential phospholipids as one of the means of protection against negative changes associated with changes in the gravity field acting on the cell.