Lipid composition of plasma membranes of rooster sperm (Gallus gallus domesticus) and its dynamics during cryopreservation

Abstract

The structural features of the plasma membranes of avian sperm make them more sensitive, compared to those of mammals, to low-temperature stress. The qualitative and quantitative composition of membrane lipids can become a determining factor in the development of new effective compositions of cryoprotective media. The purpose of the study was to determine the lipid composition of the plasma membranes of native rooster sperm, the content of carbohydrates and polyols in their cytosol, as well as dynamic changes in the membrane lipidome and cytosol composition under the influence of the cryopreservation protocol, depending on the composition of the cryoprotective medium. The studies were carried out on Rhode Island roosters (n=10), the total and progressive sperm motility and membrane damage were determined. Semen freezing and thawing was carried out using fast protocols. To determine the lipid composition of the plasma membranes of sperm and the composition of their cytosol, a chromatographic analysis method was used. The following were identified in the membranes of native spermatozoa: phospholipids, glycolyllipids and neutral lipids, represented by phosphatidylethalamine, phosphatidylserine, phosphatidylcholine, sphingomyelin and sterol. A change in the ratio between membrane lipids of the inner and outer layers of the plasma membrane of rooster spermatozoa under the influence of the cryopreservation protocol was shown. In native spermftozoa this ratio was 41.2% and 39.4%, respectively, in thawed sperm when using the LCM-control medium – 38.3% and 47.2%, respectively, when using the LCM-T20 medium - 40.7% and 44.5%, respectively. There was a significant decrease, more than 3 times, in the total amount of carbohydrates (fructose, glucose, trehalose) and polyols (glycerol, mannitol, inositol) in the cytosol of frozen/thawed spermatozoa when using the cryoprotective medium LCM-control compared with the values of the native spermatozoa - 0 .1145 mg/ml and 0.0360 mg/ml, respectively. When using the LCM-T20 medium, the change was insignificant and the delta was 5.2%. The effectiveness of using cryoprotective medium LCM-T20 containing trehalose has been proven to maintain the lipid membrane architecture of rooster spermatozoa, the carbohydratepolyol composition of their cytosol and, as a consequence, the morphofunctional usefulness of gametes during the freezing/thawing process.