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.