Abstract :
Recently, comprehensive studies were conducted regarding the reproductive development,
age at puberty, spermatogenesis and the protein profile in the seminal plasma of Santa
Ines rams. Despite the abundant information obtained from these studies regarding these
tropically adapted rams in Brazil, it is still unclear how sperm parameters relate to the
expression of molecular components of the reproductive tract. In this regard, the present
study was conducted to determine if sperm parameters were empirically associated with
the seminal plasma proteins described in two-dimensional electrophoresis maps. Seminal
plasma proteins were separated by two-dimensional electrophoresis and the respective
maps electronically analyzed. Protein spots associated with higher or lower sperm motility
were then identified by tandem mass spectrometry. Based on sperm motility, the ejaculates
were divided into two groups: those containing up to 80% motile cells (G1; n = 11) and
those with more than 80% motile sperm (G2; n = 10). On average, 236 spots per gel were
detected. Eleven spots were significantly more intense in gels from animals with ejaculates
characterized by higher semen motility scores (G2). The intensity of three other spots was
higher in gels from the G1 group. All spots differentially expressed for G1 and G2, were
present in at least 90% of the gels. From the 13 spots differentially expressed in G1 and
G2, four spots were identified by tandem mass spectrometry. Spots expressed with more
intensity in the ejaculates with higher sperm motility (G2) were identified as arylsulfatase
A and zinc-alpha-2-glycoprotein. On the other hand, two spots associated with G1 were
identified as ram seminal vesicles protein 22 kDa (RSVP-22) and bodhesin-2. Knowledge of
these identities represents a crucial step toward the comprehension of how specific seminal
plasma proteins are related to sperm motility.
