Buffalo anti-PDC-109 antibodies improve the semen quality profiles and in-vitro zona binding index and minimize the cryoinjury of sperm in cryopreserved buffalo semen

Abstract

Objective: To optimize the concentration of PDC-109 protein in semen for higher cryopreservability and fertility by sequestration or neutralization of PDC-109 by its antibodies (anti-PDC-109 antibodies) in bubaline species. Methods: PDC-109 protein was purified by applying two-step chromatography procedures. Purified protein was injected in rabbits to raise antibodies. These raised anti-PDC-109 antibodies were used in neutralization or sequestration of PDC-109 in in-vitro model. Ejaculates were collected from buffaloes and splited for four groups. Group 1 received egg yolk Tris glycerol extender, without anti-PDC-109 antibodies, while group 2 to 4 received anti-PDC-109 antibodies 266 μg/mL, 80 μg/mL, and 26 μg/mL in Tris-fructosecitrate buffer, respectively. Semen quality parameters viz., forward progressive motility, viability, total morphological abnormality, acrosomal integrity, plasma membrane integrity, cryoinjury and in-vitro zona binding index were evaluated. Results: Semen quality parameters of neat semen were within the normal range of bubaline species. Sperm motility, livability, acrosomal integrity, plasma membrane integrity, and cholesterol content of sperm were decreased and total sperm abnormality was increased significantly in post-thaw semen compared to those in pre-freeze and fresh semen (P<0.05). Semen in group 2 had higher sperm motility, livability, acrosomal integrity, plasma membrane integrity, and cholesterol content of sperm and lower total sperm abnormality significantly compared to those in group 1, 3 and 4 at pre-freeze and post-thaw stages (P<0.05). Conclusions: Sequestration or neutralization of PDC-109 by its antibodies significantly improves pre-freeze, and post-thaw semen quality parameters and in-vitro zona binding index with simultaneously reducing cryoinjury or cryodamage in the sperm of bubaline species.