The Differences In Sperm Motility And Protein Phosphorylation Between Meishan Boar And Duroc Boar

Meishan boar and Duroc boar are high quality of pigs in breedingproduction with significant differences in reproductive performance. Thereason of the differences is unknown. The investigation in reproductiveperformance differences now mainly are focused on teat number, breastdevelopment, testes morphology and spermatogenesis. The researches onboar sperm motility indexes are rarely reported. Mammalian spermatozoasare highly specialized and basically without transcription and translationfunction. Phosphorylation of sperm is important in stimulating spermacrosome reaction, maintaining sperm hyperactivation, and guaranteeingeffective sperm-egg binding. The differences in sperm motility and proteinphosphorylation between Meishan boar and Duroc boar and the reasoncausing the differences in reproductive performance were investigated toprovide a theoretical basis for clarifying the related molecular mechanism.The results showed as follows:1. The phosphorylation degree of proteins20KDa,25KDa,35~37KDa and55KDa and the tyrosine phosphorylation degree of proteins25KDa,30~40KDa,55KDa and75KDa in capacitated boar sperm weresignificantly higher than those in un-capacitated boar sperm. cAMP (1mM)or IBMX(0.1mM) in capacitated media improved phosphorylation ofproteins25KDa and55KDa with a time-dependent rule. PKA inhibitorH-89inhibited proteins25KDa~37KDa and50~75KDa phosphorylationwhich showed protein phosphorylation was regulated by sAC/cAMP/PKAin boar sperm.2. There was a similar changing trend between the values of spermmotility parameters VCL and the degree of PKA substrate phosphorylation. PKA substrate phosphorylation positively correlated with sperm motilityduring capacitation in boar sperm.3. The immunofluorescence assay showed that the sites of PKAsubstrate phosphorylation mainly distributed over acrosome cap,post-acrosome and tails (midpiece, principalpiece and endpiece) ofcapacitation boar sperm, and tyrosine phosphorylation mainly occurred atimplantation fossa and tail, especially midpiece.4. The sperms motilities in Meishan and Duroc boar weresignificantly different, and the VCL in Meishan boar sperm (212.4μm/s)was significantly higher than that in Duroc boar sperm (195.7μm/s)(P<0.05).5. It was asynchronism that sperm protein PKA substratephosphorylation in Meishan boar and Duroc boar occurred. Especially,phosphorylation degree of protein270KDa highly related with spermmotility in Meishan boar sperm was significantly higher than that in Durocboar sperm after1.5hr capacitation incubation. Protein150KDa tyrosinephosphorylation was similar with270KDa.It can be concluded that the differences in reproduction performancebetween Meishan boar and Duroc boar are due to the different degree ofPKA substrate phosphorylation and sperm motility during capacitation.